Prophylaxis In severe and recurring cases of hereditary angioedema, tranexamic acid or anab olic steroids (e.g. danazole boosts liver production of C1-esterase inhibitor) are effectiv e, but the latter is rarely used in childhood due to its androgenic effects. Molluscum contagiosum Common pox virus infection affecting infants and young children. Presentation Pink umbilicated (central dimple) papules. Usually affects moist areas, but ca n occur anywhere. Exacerbated by active eczema or topical steroids. Treatment None if uncomplicated as usually spontaneously resolves within a year. If problem atic: \200 \200 \200 \200 Scabies See b p.829 Viral warts See b p.826 Treat any associated eczema. Pinch forcep liquid nitrogen cryotherapy. Lesion curettage. Ap plication of benzoyl peroxide 5% daily. 22_McClure_22.indd 813 11/14/2012 3:29:33 PM CHAPTER 22 Dermatology 814 Papular rashes (2) Papular urticaria Hypersensitivity reaction to insect bites. Itchy small red papules or vesicles evolve into 1 \200\2235mm papules +/ \200\223 surrounding urticari a or surface crusting. Usually on limbs and buttocks. May last for weeks and be exacerbated by new bites elsewhere. Secondary infection common. Treatment \200 \200 \200 Prevent new bites. Antipruritics (e.g. oral antihistamines, topical steroids). Antibiotics for any s infection. Keratosis pilaris Common. Any age. Horny plugging of follicles causes asymptomatic rough pa pular rash +/ \200\223 erythema. Affects upper outer arms, front of thighs, cheeks. Treatment Reassurance; emollients, especially urea-based creams. Papular acrodermatitis (Gianotti \200\223Crosti syndrome) \200 \200 Acute, non-itchy, red papules appear over face, limbs, and buttocks. Asymptomatic or accomp anied by malaise, hepatomegaly, lymphadenopathy. Causes \200 \200 \200 \200 Enteroviruses. EBV. Adenovirus. Mycoplasma. Treatment Reassurance. Prognosis Spontaneously resolves after a few weeks. 22_McClure_22.indd 814 11/14/2012 3:29:33 PM PAPULAR RASHES (2) 815 22_McClure_22.indd 815 11/14/2012 3:29:33 PM CHAPTER 22 Dermatology 816 Vesiculobullous rashes Erythema multiforme Cause Immunologically mediated syndrome. May be idiopathic, but usually pre- cipitated by infection (e.g. mycoplasma, herpes simplex, other viruses) or drugs (e.g. sulfonamides, penicillin). Presentation See b Plate 4. \200 Crops of characteristic symmetric \200\230target \200\231 lesions develop with pallid or p urple center surrounded by erythematous ring. May also be haemorrhagic, red macules or larg e bullae. Lesions last 2 \200\2233wks and affect hands, feet, elbows, knees. Typically, muc ous membrane ulcers occur (buccal, eye, genitalia). \200 \200 Treatment If precipitating infection recurs treat early as tends to cause rash again, e.g. topical aciclovir for recurrent HSV. \200 \200 \200 \200 Fluid maintenance. Analgesic mouthwashes. Lip emollient ointment. Oral antihistamines. Prognosis Complete recovery, but may recur. Stevens \200\223Johnson syndrome/toxic epidermal necrolysis Severe, and overlapping conditi on with erythema multiforme except usu- ally drug induced with viral infection rarely impli cated. Presentation See b Plate 5. \200 Widespread blisters/bullae over erythematous, purple macular, or haemorrhagic skin. Mucous membranes often affected with haemorrhagic crusting. Rubbing may cause skin separation at e pidermodermal junction (= positive Nikolsky sign). Also possible fever, arthralgia, myalgia , prostration, renal failure, pneumonitis, conjunctivitis, corneal ulceration, blindness. \200 Treatment \200 \200 \200 \200 (cid:1) \200 Supportive, as for severe burns (e.g. hydration, airway protection). Identify causative ant igen and remove/treat. Frequent emollient ointment. Specialist eye care. Systemic corticosteroids or immunoglobulin used in \201 rst 2 \200\2233 days may be helpful if life-threatening. Prognosis Can be life-threatening. Recovery usually occurs in 3 \200\2234wks. 22_McClure_22.indd 816 11/14/2012 3:29:33 PM VESICULOBULLOUS RASHES 817 Staphylococcal scalded skin syndrome Exotoxin-mediated epidermolysis s to Staphylococcus au reus infection (which may be trivial). Occurs in children <5yrs. Presentation \200 Extensive tender erythema with \202 accid super \201 cial blisters/bullae ( \200\230scal ded appearance \200\231). Erosions and +ve Nikolsky sign. Crusting around eyes and mouth, f ever. \200 Treatment \200 \200 \200 Supportive treatment and analgesia. IV anti-staphylococcal antibiotics. Gentle skin care, e mollient ointments. Prognosis Rapid recovery without scarring. Impetigo Highly contagious Staphylococcus aureus or B-haemolytic streptococcal super \201 cial skin infection. May be p or complicate other skin disease (e.g. HSV infection, eczema, scabies). Risk factors include overcrowding and poor hygiene. Presentation \200 Super \201 cial, rapidly spreading initially clear blisters that rapidly develop into stra w-colored \200\230dirty \200\231 looking lesions with yellow crusting. Often starts around nose and face; neonates may develop bullous impetigo. Risk of staphylococcal scalded skin syndrome or acute glomerulonephritis (streptococcal). Investigation Skin swabs for bacterial culture and sensitivity. Treatment Rapidly resolves if: \200 \200 \200 Eczema herpeticum See b p.826 bathe crusts off using antiseptics (contain infectious bacteria); antibiotics (e.g. topical mupirocin 2% ointment or oral \202 ucloxacillin); treat any predisposing condition. Traumatic blisters Caused by friction, burns, or insect bites. Sterile aspiration of bliste r within 12hr after appearance, and pressure dressing may be curative. Epidermolysis bullos a See b Plate 6 and b p.840 Other viruses See b pp.826 \200\223827 22_McClure_22.indd 817 11/14/2012 3:29:33 PM CHAPTER 22 Dermatology 818 Red blanching (erythematous) rashes Causes vary with age. Viral causes commonest in younger children. In older children, eczema, psoriasis, and drug reactions (e.g. reaction to am- p icillin in glandular fever) predominate. Viruses (exanthem) See b pp.704 \200\223709. See b Plate 7. Culprits include: \200 \200 \200 \200 \200 \200 \200 \200 \200 adenovirus; enteroviruses (coxsackie or echovirus); EBV; in \202 uenza; parain \202 uenza ; human herpes virus 6 (roseola infantum); parvovirus b19 (erythema infectiosum); rubella; measles. Usually associated with fever and widespread non-speci \201 c macular or mac- ular \200 \223papular erythematous rash. If child is signi \201 cantly unwell, lethargic, or periphe ral perfusion is reduced, admit and investigate (may be bacterial sepsis). Otherwise, simpl y reassure and advise symptomatic treatment. Drug eruptions Erythematous macular \200\223papular rash commonest (e.g. to penicillins, ce pha- losporins, anticonvulsants). Drugs may also cause: \200 \200 \200 Urticaria (e.g. opiates, NSAIDs, penicillins, cephalosporins). Exfoliative dermatitis (e.g. sulphonamides, allopurinol, carbamazepine). Erythema multiforme or Stevens \200\223Johnson syndrome/toxic epidermal necrolysis (e.g. anticonvulsants, antibiotics and allopurinol). Treatment \200 \200 Discontinue offending drug, may need prick or patch testing to identify. Symptomatic treatm ent (e.g. antihistamines or emollients for pruritus). Erysipelas and cellulitis Conditions overlap. Erysipelas is super \201 cial skin infection whereas cellulitis involves deeper subcutaneous tissues. Usually due to Strep. pyogenes or Staph. aureus; occasionally Haemophilus in \202 uenzae. Presentation \200 \200 \200 \200 Tender, warm, spreading, sharply marginated erythema +/ \200\223 oedema. May also have asce nding red streaks of lymphangitis. Regional lymphadenopathy, fever, malaise. Deeper infecti on may co-exist, e.g. osteomyelitis. Management \200 \200 \200 Swab skin and blood culture. If erysipelas alone, IV penicillin (erythromycin if penicillin -allergic). Cellulitis: \202 ucloxacillin. Consider cefotaxime instead of penicillin if c hild aged <5yrs and not immunized against Haemophilus. raise affected part (e.g. limb); combination of IV penicillin and 22_McClure_22.indd 818 11/14/2012 3:29:33 PM RED BLANCHING (ERYTHEMATOUS) RASHES 819 Erythema marginatum Crops of pink truncal rings (lesions fade rap- idly, only to recur) cau sed by rheumatic fever. No treatment required. Erythema nodosum Typically affects older children. Caused by immunological reaction to: \200 \200 \200 \200 \200 \200 \200 Tuberculosis. Streptococcal infection. Mycoplasma infection. IBD. Sulphonamides. Viruses. I diopathic (30%). Presentation Multiple discrete, large, red, hot, tender nodules on shins (occasionally thig h and forearms) appear over 10 days. Nodules resolve over 3 \200\2236wks, with color change s similar to fading bruises. Fever, malaise, arthralgia, particularly of knees, may also oc cur. Management Investigate for infection. Treat underlying disease; give analgesics. Sunburn See also b p.1024. Caused by excessive UV light exposure. Sun avoid- ance, skin cov ering, hats, and water-resistant high-factor sunscreens are preventative! Fair-skinned indi viduals, infants, and those with pre-existing hypopigmented disorders are at particular ris k. \200 Presentation: Resolves with skin peeling. Treatment: \200 \200 \200 \200 painful, tender erythema +/ \200\223 blistering over exposed area. Antipyretics; Analgesics; topical calamine lotion; topical corticosteroids if severe. Intertrigo \200 Cause: \200 \200 Presentation: \200 excessive friction between skin surfaces; obesity is a predisposing factor. moist, erythematous eruption typically affecting the groin, axillae, neck, submammary areas ; s \200 Treatment: \200 Candida infection common. treat in \202 ammation and infection, e.g. topical antibiotic, topical antifungal and low potency topical steroid; improve general hygiene; expose to air. \200 Kawasaki disease See b p.716 Septicaemia Meningococcal disease, as well as other bacterial patho- gens, can present with an erythematous rash (see b p.714). 22_McClure_22.indd 819 11/14/2012 3:29:34 PM CHAPTER 22 Dermatology 820 Pruritus Is the sensation provoking a desire to scratch? If severe, it leads to excoria- ti on, papules or nodules (localized skin thickening), and licheni \201 cation. Generalized pruritus Causes \200 \200 \200 \200 \200 \200 \200 \200 Skin diseases (see Localized pruritus, p.820). Hepatic disease (bile salts). Food or drug r eaction/allergy (e.g. penicillin). Underlying malignancy, particularly lymphoma. Chronic re nal failure. Hypo- or hyperthyroidism. Parasites (e.g. scabies). Iron de \201 ciency anemi a. Investigation In absence of obvious underlying skin disease: \200 \200 \200 \200 \200 \200 \200 \200 FBC. Blood \201 lm. CRP/ESR. Ferritin. LFT. U&E and creatinine. Glucose. TFT. Treatment \200 \200 \200 \200 Treat causative disease. Bland topical emollients. Emollient bath oils. Night-time sedative , e.g. antihistamines. Localized pruritus Causes \200 \200 \200 \200 \200 \200 \200 \200 \200 Atopic eczema (cheeks, hands, and limb \202 exures). Contact dermatitis. Urticaria. Insec t bites. Fungal infection (e.g. tinea capitis). Head lice (pediculosis capitis). Scabies ( \201 nger webs, wrists, groin, buttocks). Psoriasis. Dermatitis herpetiformis (elbows, sho ulders, genitalia, perineum, buttocks). Pityriasis rosea. Chickenpox. Dermatitis artefacta (!). \200 \200 22_McClure_22.indd 820 11/14/2012 3:29:34 PM PRURITUS 821 Investigation In absence of obvious underlying skin disease, investigate as for generalized pruritus. Treatment As for generalized pruritis. Pruritus ani Localized peri-anal itching. Causes \200 \200 \200 \200 \200 \200 \200 \200 Threadworms. Anal disease (e.g. anal \201 ssure, hemorrhoids, Crohn \200\231s disease). P oor hygiene. Chronic fecal soiling. Chronic diarrhea. Localized skin disease (e.g. candidia sis, psoriasis). Contact dermatitis (e.g. to toilet paper). Idiopathic. Investigation Threadworms may be seen during anal inspection or their eggs seen on microsco py of \200\230sellotape \200\231 applied to the anus or skin swab culture. Treatment \200 \200 \200 Treat underlying disease. Improve perianal hygiene. Mild topical steroid may relieve once i nfective cause is excluded. Pruritus vulvae Localized perivulval itching. Causes \200 \200 \200 \200 \200 \200 \200 Idiopathic. Poor hygiene. Infection (e.g. candidiasis, trichomoniasis). Diabetes mellitus. Threadworm. Contact dermatitis. Localized skin disease (see pruritus ani), e.g. lichen scle rosus. Treatment As for pruritus ani. 22_McClure_22.indd 821 11/14/2012 3:29:34 PM CHAPTER 22 Dermatology 822 Pustular rashes Generalized pustulosis is unusual. When the child is <2yrs, immunode- \201 ciency, particularly phagocyte dysfunction, should be excluded. Local causes in older children include: \200 \200 \200 \200 \200 \200 acne vulgaris; folliculitis; impetigo (see scabies (see perioral dermatitis; pustular psori asis (see b pp.718, 817); b p.829); b p.810). Acne vulgaris Acne affects 90 \200\223100% of teenagers. However, acne may occur in neo- na tes (spontaneous improvement without treatment occurs), infant (often requires treatment an d may imply severe acne in later years) and adult (often women older than 25). Cause follicle, Excess Propionibacterium acnes bacterial proliferation and in \202 ammatio n of the hair follicle lead to acne. sebum production, hyperkeratosis of the hair Hyperandrogenism should be suspected if \200\224acne is severe, sudden and of early onset; if there are other signs of hyperandrogenism including irreg- ular periods, hirsuitism, mal e or female pattern hair loss and deepening of the voice in women; or there is treatment re sistance. Diet has not yet been proven to impact acne, but a healthy diet and exercise are recommended. Presentation In \202 ammatory (papules, pustules and nodules and cysts) and comedonal (bla ckheads and whiteheads) acne. There may be hypertrophic and/or atrophic scarring. Acne may affect the face, back, and chest. Treatment \200 General measures: \200 \200 Speci \201 c measures: \200 \200 \200 \200 use a gentle soap free cleanser daily; use oil free and non-comedogenic make-up. topical retinoids for comedonal acne, e.g. adapalene, tretinoin; topical antibiotics for in \202 ammatory acne, e.g. clindamycin; topical benzoyl peroxide 2.5 \200\2235% for in \202 ammatory acne; oral antibiotics for in \202 ammatory acne, e.g. erythromycin, tetracy clines; oral isotretinoin if severe or unresponsive to above (side-effects: teratogenic, av oid in teenage pregnancy; headaches; myalgia; dry skin/mucous membranes; sun photosensitivi ty). Prognosis Resolves, but may persist for years in some cases. Psychological support is impor tant. 22_McClure_22.indd 822 11/14/2012 3:29:34 PM PURPURIC RASHES 823 Purpuric rashes Causes \200 \200 \200 \200 \200 \200 \200 Viral infections, most commonly enteroviral. Septicaemia, most commonly meningococcal (see Thrombocytopenia, platelet, or clotting disorders. b p.788 and b Plate 8). Vasculitis, e.g. HSP (see Trauma, including NAI. Drug reactions. Vasomotor straining, e.g. strenuous coughi ng or isometric exercise. b p.714). Management If the patient is well and there is an obvious benign cause, reassure as the ras h will resolve spontaneously. If cause unclear, initial investigations should include: \200 \200 \200 \200 \200 \200 \200 \200 FBC. Blood \201 lm. Clotting studies. Blood cultures. Check BP, urinalysis, blood U&E and ASOT (if HSP likely). If sepsis possible, admit and start IV antibiotics. Stop any drug li kely to be causative. Consider a skin biopsy if diagnosis remains unclear. Lymphoedema Diffuse soft tissue oedema due to inadequate lymphatic drainage. May be due to developmental defect, e.g. congenital lymphoedema (isolated or part of Turner \200\231s syn drome) or cystic hygroma (which also commonly has a vascular component). Secondary causes i nclude \200\224surgical lymphatic destruction; malignant in \201 ltration; irradiation; re current lymphangitis; par- asitic infestation (in the tropics \200\224 \201 lariasis or el ephantiasis). Presentation \200 \200 \200 Pitting \201 rm swelling. +/ \200\223 Hypertrophy of affected limb. Lymphangiography may be helpful to identify the area of obstruction. Treatment Is often dif \201 cult. Limb elevation, pressure garments, or diuretics may be h elpful. Give oral penicillin prophylaxis for increased risk of erysipelas. 22_McClure_22.indd 823 11/14/2012 3:29:34 PM CHAPTER 22 Dermatology 824 Blood vessel disorders Telangiectasia Telangiectasias are permanently dilated small vessels . Commonest are spi- der naevi (dilated capillaries radiating from central arteriole). Less than 5 are considered normal. Laser or cautery of central vessel is rarely re- quired. Fiv e or more telangiectasias may be part of: \200 Hereditary haemorrhagic telangiectasia (autosomal dominant genetic disorder with telangiect asia on lip, tongue, nasal epithelium, risking recurrent epistaxis +/ \200\223 GI hemorrhag e). Ataxia telangiectasia (see Hereditary benign telangiectasia. \200 b p.724). Vascular malformations Salmon patches Occur on nape of neck, glabella, eyelids and other si tes. Often resolve or improve with age (see b p.196). Port wine stain Naevus \202 ammeus (see b Plate 9). A capillary vascular malformation evi- dent at birth, which persists with age. Vivid red or purple macule. May af- fect any site, but face and neck commonest. Involv ement of the eyelid may be associated with glaucoma; segmental ophthalmic branch of trigemi nal nerve involvement is associated with a risk of Sturge \200\223Weber syndrome (seizures, hemiplegia, mental retardation). Treatment is pulse dye laser. Klippel \200\223Trenaunay syndrome A complex venous-lymphatic malformation of the limb asso ciated with limb hypertrophy and varicose veins. Patients may be at increased risk of DVT/p ulmonary embolism (PE). Treatment is compression stockings. Lymphatic leakage may be treate d with pulse dye laser or CO2 laser. Haemangiomas (see b Plate 10) \200 There are several types, but the most common by far is the infantile haemangioma (strawberr y naevus). These occur in 10% of infants. They often present in the \201 rst few weeks of life and are more common in females. May have a super \201 cial (red color) and deep (blu e color) component. They often undergo a rapid proliferative phase between 4 \200\2239mths of age and then slowly involute over years. Complications include ulceration, bleeding and infection. If segmental over the face and perineum, they may be associated with PHACES (pos terior fossa abnormalities, haemangioma, arterial anomalies, cardiac anomalies, eye abnorma lities, sternal cleft or supra-umbilical raphe) and PELVIS (perineal haemangioma, external genital anomalies, lipomyelomeningocele, vesicorenal abnormalities, imperforate anus and sk in tags) syndromes respectively. Those in the beard area may cause airway obstruction and t hose in the lumbar midline may be associated with spinal dysraphism. Multiple cutaneous hae mangiomas may be associated with internal organ haemangiomas (especially liver and brain). \200 22_McClure_22.indd 824 11/14/2012 3:29:34 PM BLOOD VESSEL DISORDERS 825 Infantile haemangiomas have no risk of Kassabach-Merritt Syndrome (comprises thrombocytopae nia and a consumptive coagulopathy; only occurs in tufted angiomas and kaposiform haemangio endotheliomas). Treatment Reassurance and monitoring in most cases is all that is required. However, those in critical or cosmeticially sensitive sites may now be treated with oral propranolol by a dermatologist. Pulse dye laser is a useful treatment for ulceration and residual telangiect asia after involution. Surgical correc- tion may be required to remove the \201 brofatty residual after involution of large haemangiomas. Segmental, midline and multiple haemangiom as may need further investigation (see b p.824). Perniosis (chilblains) Abnormal reaction to cold with localized, in \202 ammatory, red-blu e lesions on extremities (e.g. digits, ears). On rewarming there is pain or itching. Lesion s may ulcerate. Resolves spontaneously. Prevented by warm cloth- ing and housing! Raynaud \200\231s syndrome Episodic artery spasm causes digital ischaemia. The condition is precipi- tated by cold, \201 nger constriction (e.g. shopping bags), or emotion. Most ca ses improve with age. Syndrome may be idiopathic (Raynaud \200\231s disease) or s (Raynaud \200\231s phenomenon) to: \200 \200 \200 Systemic sclerosis. Arterial occlusion (e.g. cervical rib). Occlusive arterial disease. Presentation Fingers ache, burn, or tingle with color changes of pallor (ischaemia), blue ( cyanosis), and red (reactive hyperaemia). Treatment \200 \200 \200 \200 Treat underlying disease. Local warmth. Nifedipine. Consider sympathethectomy if severe or recurrent. 22_McClure_22.indd 825 11/14/2012 3:29:34 PM CHAPTER 22 Dermatology 826 Skin infection: viral and bacterial Viral Warts Very common. Caused by infection with human papilloma virus. May affect any age, but mainly school-aged children. Warts exists as pain less \201 rm papules with rough hyperkeratotic surface. Capillary ends can usually be see n super \201 cially. Typically affect hands, knees, face, and feet. Usually resolve sponta neously within 3yrs. \200 Plantar warts (verrucae) may be painful due to pressure-induced in growing. Genital or peri anal warts (condyloma acuminata) may occur and, although sexual abuse should be considered, causation is commonly innocent. Treatment Not usually needed. If painful or embarrassing: \200 \200 \200 \200 keratolytic agent (e.g. salicylic acid); liquid nitrogen cryotherapy; immunotherapy; surgic al removal. Molluscum contagiosum See b Plate 11 and b p.813. Herpes simplex Most cases due to type I H SV. Type II HSV typically causes genital herpes. Co-infection with active atopic eczema cau ses eczema herpeticum. Primary infection Typically occurs in pre-school children with sore throat, stomatitis, ves icles or ulceration involving mouth, lip, face, and fever. It resolves within 2wks. s \200 \200 bacterial infection frequently occurs. Treat with antipyretics, analgesic mouthwashes, or throat lozenges, topical aciclovir cream . Consider NGT \202 uids if child becomes dehydrated due to reluctance to swallow. Treat any bacterial s infection. Secondary reactivation Manifests as initial itch or tingling followed by localized vesicles that then break down. Typically lesions are perioral (cold sore). May be idiopathic, but c an be precipitated by illness, immunosuppression, menstruation. Early topical aciclovir cre am aborts episode or reduces its severity. 22_McClure_22.indd 826 11/14/2012 3:29:34 PM SKIN INFECTION: VIRAL AND BACTERIAL 827 Chickenpox (varicella) (see b p.710) This is a very contagious infection due to Herpes zost er. Chickenpox with fever, followed by pruritic vesicular eruption over the trunk spreading to face, mouth, and limbs. Lesions evolve at different rates so that macules, papules, ves icles, and pustules will all be present at once. Secondary bacte- rial skin infection may o ccur. Illness may cause life-threatening pneumonitis in congenital infection, older teenage rs, or immunosuppressed. Infectivity lasts until FINAL vesicle crusts over. Treatment \200 \200 \200 \200 \200 Antipyretics. Oral antihistamines. Cooling baths. Topical calamine lotion. IM human-speci \201 c given early if risk of severe illness (IV aciclovir in severe illness). Varicella zoster immunoglobulin (VZIG) should be Reactivation (shingles) Can occur in childhood, particularly when varicella occurs <1yr old . May be severe in immunosuppressed. Presents with localized unilateral pain, itching, or h yperaesthesia, followed by vesicular eruption in the distribu- tion of affected dorsal root ganglia. Treat with oral aciclovir if severe and topical antibiotics if s bacterial infect ion. Hand, foot, and mouth disease Infection with coxsackie or enterovirus 71, usually in p re-school children. (Note: Completely different infection from foot and mouth disease in an i- mals!) Painful small vesicles (may be linear or oval) affect mouth (stomati- tis), palms , and soles, and occasionally nappy area. Lesions spontaneously resolve within 10 days. If uncertain a viral swab can con \201 rm the diagnosis and also exclude potentially more ser ious HSV/VZV infection. Treatment Symptomatic. Bacterial Impetigo See b pp.718, 817. Erysipelas/cellulites See b p.818. Furuncle (boil) \200 \200 Con \202 uence of furuncles = a carbuncle. Hair follicular abscess (boil) is usually due t o infection. Common in post-pubertal males. Tender super \201 cial red papule develops int o large painful in \202 amed pustule that ultimately discharges super \201 cially. Affect s mainly the back, axilla, and buttocks. Associated with diabetes mellitus and poor hygiene . Recurrent or severe furuncles require surgical drainage, oral \202 ucloxacillin, and da ily chlorhexidine baths to decrease S. aureus skin colonization. Staphylococcus aureus \200 \200 22_McClure_22.indd 827 11/14/2012 3:29:34 PM CHAPTER 22 Dermatology 828 Fungal skin infections Dermatophyte infection Tinea corporis (ringworm) Annular scaly lesio n. Central clearing and sharp edge on trunk, face, or limbs. Investigation Skin scrapings for microscopy and culture. Treatment Topical antifungals, e.g. an imidazole cream, terbina \201 ne cream. Tinea capitus (scalp ringworm) Red, scaling scalp lesions with hair loss and short hair stu mps. May pres- ent as tender erythematous patch with pustules (kerion). Investigation as fo r Tinea corporis. Skin lesions appear \202 uorescent green under Wood \200\231s light. Investigation Skin scrapings and hair pull for microscopy and culture. Treatment Topical antifungal shampoo for one week and 6 \200\2238wks oral gri- seofulvin 20 mg/kg/day (plus oral steroids if kerion exists). Tinea pedis (athlete \200\231s foot) Itchy, irritable skin between the toes +/ \200\223 sol e of foot. Treatment Topical antifungal. Tinea unguium (onychomycosis) Nail infection causes discolored, friable, and deformed nails . Investigation Microscopy and culture of nail clippings. Treatment Oral antifungal for 3mths (e.g. terbina \201 ne). Candida albicans infection Predisposing factors \200 Moist body folds. \200 Treatment w ith broad-spectrum antibiotics. \200 Immunosuppression. \200 Diabetes mellitus. Variants include the following: \200 b Plate 12). Macular Cutaneous candidiasis (e.g. napkin rash; see erythema, slight scaling, small outlying \200 \230satellite \200\231 lesions, in body folds. Chronic paronychia. Chronic mucocutaneous gr anulomatous candidiasis ( immunode \201 ciency disorder). \200 s to congenital Investigations Skin scrapings for microscopy and culture. Treatment Oral or topical anti-candidal drugs, e.g. nystatin, \202 uconazole. Pityriasis versicolor (Tinea versicolor) Malassezia infection in post-pubertal children. As ymptomatic hypo/hyper- pigmented macules and scaling on trunk/upper limbs. Treatment Topical imidazole foaming lotion for 3 consecutive nights. 22_McClure_22.indd 828 11/14/2012 3:29:35 PM PARASITIC SKIN INFECTIONS 829 Parasitic skin infections Scabies \200 \200 \200 Caused by Common at all ages. Diagnosis is not easy, so look closely for clues. Classically it causes itchy papular rash with visible burrows affecting \201 nger and toe webs, palm s, soles, wrists, groin, axillary folds, buttocks (truncal in infants). Excoriation, eczema tization, urticaria, or impetigo may develop. Diagnosis is con \201 rmed by microscopy of mite removed from burrow (rarely needed). Sarcoptes scabiei mite. Treatment \200 Treat whole household and close contacts simultaneously with 12hr topical application below the head (in children <2yrs old all body except face) with permethrin cream (5%) or 24hr o f malathion liquid (0.5%) washed off and then repeated the next day. Simultaneously Antihis tamines or calamine lotion for itch, which may last for 10 days. Apply weak topical cortico steroid if scabies nodules are present. \200 \200 , launder bed linen and underwear in a warm wash. Lice \200 Infestation with (body), or Phthirus pubis (pubic area \200\230crabs \200\231). Common in all ages. Localized pruritis, Lice are dif \201 cult to see, but small white eggs (nits) a re easily seen attached to hair shafts. Pediculus capitus (scalp \200\230nits \200\231), Pedicularis corporis \200 \200 s impetigo or regional lymphadenopathy. Treatment Daily thorough combing with \201 ne-toothed comb combined with single shampoo w ith lotions of carbaryl (0.5%) or malathion (0.5%). Other insects Many biting insects (e.g. \202 eas, midges, bedbugs, mosquitoes) may cause erythematous macular lesions with central punctum or papular urticaria. Treatment \200 \200 \200 \200 Avoid bites, e.g. treat infested pets. Oral antihistamines. Topical steroids. Antibiotics i f there is s bacterial infection. Protozoal skin infections Cutaneous leishmaniasis Infection with Leishmania spp. Endemic in hot climates (e.g. Mediterranean, South America). Spread by sand \202 ies. Large red-brow n papule, nodule, ulcer, or granuloma develops on face after several months incubation. Inf ection usually resolves within 1yr, but leaves a scar. Treatment Intralesional or IV antimony compound if severe. 22_McClure_22.indd 829 11/14/2012 3:29:35 PM CHAPTER 22 Dermatology 830 Hair disorders Hair absence or loss Alopecia areata \200 \200 \200 Commonest cause of hair loss. An autoimmune disease. Hairless, smooth areas are most often on the scalp. At the margin short remnants of broken hairs are visible ( \200\230exclamatio n marks \200\231). All of the scalp (alopecia totalis) or the whole body (alopecia universa lis) may be involved. Hair typically regrows after 6 \200\22312mths, but may be recurrent. The larger the area of hair loss, the poorer the prognosis. \200 Traumatic hair loss May be unintentional (e.g. chronic hair twisting due to ponytail or rub bing of occiput in babies) or intentional (trichotillomania) due to hair pulling, twisting, or cutting as part of habit or s to anxiety, chronic social depri- vation, or psychologica l disorder. Characteristically, there is an irregular margin, as well as bizarre patterns w ithout complete hair loss, and broken hairs of different length. Hair re-grows once behavio r is modi \201 ed. Scalp infection Tinea capitus, ringworm (see b p.828). Scarring alopeci a Commonest cause is aplasia cutis. Circumscribed areas of the skin are absent, usually on scalp, which presents at birth with raw, red ulcer that heals with scarring and later absen t hair growth. There is a signi \201 cant incidence of other abnormalities (e.g. trisomies ). Irreversible absent local- ized hair growth will also follow other causes of trauma (e.g . burns, skin disease, trauma). Congenital diffuse alopecia A rare autosomal recessive condition. Hair is present in the ne wborn pe- riod, but total hair loss occurs over the next few months and does not regrow. Ma y be associated with other anomalies. Systemic disease Hair loss can be s to hypothyroidism , diabetes mellitus, severe systemic disease, iron or zinc de \201 ciency, chemotherapy. Management of hair absence or loss \200 include general health, recent illnesses, drug history, family History: history of alopecia, age of onset. Examination: Investigations: Treat any underlyi ng condition. Wigs may be helpful. Topical steroids may be helpful for alopecia areata. \200 \200 \200 \200 pattern of hair loss; scalp and general examination. hair M,C&S; Wood \200\231s light (tine a capitus); scalp biopsy. 22_McClure_22.indd 830 11/14/2012 3:29:35 PM HAIR DISORDERS 831 Excessive hair Hypertrichosis De \201 ned as hair growth in areas not normally hairy in ei ther sex. Causes \200 \200 \200 Racial. Familial. Certain rare syndromes (e.g. Cornelia De Lange syndrome, mucopolysacchari dosis). Drugs (e.g. diazoxide, ciclosporin, minoxidil). Anorexia nervosa. Protein-energy ma lnutrition. Persistence of fetal lanugo hair at birth. \200 \200 \200 Localized hypertrichosis may be associated with pigmented naevi, spina bi \201 da occulta, in \202 ammatory skin diseases, or topical steroids. Treatment If required remove or treat underlying cause if possible; hair removal using depi latory creams or waxing. Hirsutism Male pattern of hair growth in females. Causes \200 \200 \200 Racial. Familial. Androgen excess (adrenal hypoplasia or tumor, Cushing \200\231s disease, polycystic ovary syndrome). Turner \200\231s syndrome. Drugs (e.g. anticonvulsants, progest erones, anabolic steroids). \200 Investigate If there is any suggestion that not racial or familial (e.g. virilization evide nt). \200 \200 \200 \200 \200 \200 FBC. Plasma free testosterone. Plasma 17-OH progesterone. Serum cortisol. Urine steroid pro \201 le. Skull X-ray to detect possible pituitary tumor. Treatment Treat any underlying disease; reassure if racial or familial; hair removal using depilatory creams or waxing. Hair diseases All diseases are rare and include: \200 \200 wiry wool hair (b p.976); a rare autosomal dominant condition that causes brittle Menkes kinky hair disease: Monilethrix: hair that fails to grow and breaks at 1 \200\2232cm ; Pili torti: \200\230 \202 ickers \200\231 under direct light; Wooly hair syndrome: Cauc asians. hair repeatedly twists over 180*, leading to brittle hair that wiry wooly Afro-Caribbean-like hair in 22_McClure_22.indd 831 11/14/2012 3:29:35 PM CHAPTER 22 Dermatology 832 Nail disorders Paronychia Acute paronychia Common, particularly in newborns. It presents as acute in \202 ammation and tenderness of nail folds and surrounding skin. Treatment Topical antiseptics, and, if severe, oral antibiotic, e.g. cephalexin. Chronic paronychia Associated with nail dystrophy. It is usually caused by chronic wetness (e.g. thumb sucking, resulting in infection with mixed bacteria and Candida). Treatment Keep nail dry; topical nystatin and antiseptics. Tinea unguium (onychomycosis) Se e b p.828. Nail biting Common habit. Permanent nail damage may occur if nail matrix dam- aged. Treatment Gentle dissuasion! Proprietary topical nail solutions that impart a very unpleasa nt taste may be effective. Ingrowing toe-nails Most commonly involves the hallux. A spicule of nail grows into lateral nail fold leading to pain, bacterial paronychia, and granulation tissue. Treatment \200 \200 \200 \200 Local antiseptic. Careful trimming of nail spicule. Education on correct toe-nail cutting. Silver nitrate cauterization of granulation tissue or radical surgery is required when seve re. Subungual hemorrhage Caused by trauma leading to hemorrhage under nail. Perforation of nail with hot needle is curative and relieves pain immediately. 22_McClure_22.indd 832 11/14/2012 3:29:35 PM NAIL DISORDERS 833 Nail abnormalities secondary to generalized disease \200 Congenital abnormal nails (usually atrophic) may be due to rare inherited conditions, e.g. ectodermal dysplasia. s to chronic pulmonary suppuration, e.g. cystic \201 brosis, Clubbi ng: \201 brosing alveolitis, bacterial endocarditis, cyanotic congenital heart disease, m alabsorptive states, IBD, hepatic cirrhosis. Onycholysis: trauma, eczema. Koilonychia: (Koi lonychia is normal in the \201 rst few months of life.) Nail pitting: Beau \200\231s line : Splinter hemorrhages: Yellow nail syndrome: the lungs). Nail \200\223patella syndrome: ra re autosomal dominant condition with small rudimentary patella, elbow deformities, reduced or longitudinal split nails. Rarely, chronic glomerulonephritis develops. premature separation of nail from nail bed due to psoriasis, spoon-shaped nails due to chronic iron de \201 ciency anemia. \200 \200 \200 occurs in psoriasis, eczema, alopecia areata. transverse groove in nail caused by severe sy stemic illness. due to bacterial endocarditis, trauma. due to defective lymphatic drainage (also affects 22_McClure_22.indd 833 11/14/2012 3:29:35 PM CHAPTER 22 Dermatology 834 Photosensitivity and light eruptions Photosensitivity Reactions to sunlight can be precipit ated by drugs (e.g. thiazide diuretics, nalidixic acid), soaps, perfumes, plant pollens, pl ant contact (e.g. giant hog- weed plant). Most common is a dermatitis-like reaction, but al so it may be erythematous or blistering. Porphyria Some forms are photosensitive, e.g. erythropoietic protoporphyria (skin burning, redness, swelling, serous crusting +/ \200\223 subsequent scarring). Treatment is that of t he underlying porphyria together with sun protec- tion (see also b p.819). Juvenile spring eruption Red papules and herpetiform vesicles or blisters develop, usually in spring, over light-exposed skin, particularly ear helices. Commoner in boys. Lesions heal without scarri ng. Topical steroids hasten healing. Polymorphic light eruption Itchy, erythematous, papular rash occurring in sun-exposed areas 6 \200\22348hr after exposure. Most commonly affects adolescent girls. Treatment is with h igh factor sun screen. Actinic prurigo An uncommon condition precipitated by sunlight. Irritant papules, exuda- ti on, and excoriation develop on both exposed and unexposed skin areas. Treatment is with sun protection. Generally resolves after several years. Xeroderma pigmentosum A rare autosomal recessive condition in which hypersensitivity to sun light causes marked erythema followed by dry skin, freckles, hyperpigmentation, atrophy, an d scarring. Solar keratosis and skin cancers eventually develop due to the decreased abilit y to repair DNA damaged by UV radiation. 22_McClure_22.indd 834 11/14/2012 3:29:35 PM PHOTOSENSITIVITY AND LIGHT ERUPTIONS 835 22_McClure_22.indd 835 11/14/2012 3:29:35 PM CHAPTER 22 Dermatology 836 Pigmentation disorders Hyperpigmented lesions Generalized hyperpigmentation (hypermelanosis ) Causes \200 \200 \200 \200 \200 \200 Racial. Sun. ACTH (e.g. hypoadrenalism). Chronic renal failure ( Malabsorption. Drug reacti on. i melanocyte-stimulating hormone (MSH)). Localized hyperpigmentation (hypermelanosis) Causes \200 \200 \200 \200 \200 Pigmented naevi (see bullet points in Freckles. Lentigines. Caf au lait Neuro \201 broma tosis (before puberty diameter, axillary freckles). Viral warts. Polyostotic \201 brous d ysplasia (McAS). Peutz \200\223Jegher \200\231s syndrome (perioral brown macules); post-in \202 ammatory skin disease or trauma. Pigmented naevi, following). macules. (cid:2)6 caf au lait macules >0.5cm \200 \200 