ExcoriationTraumaticlesionbreakingtheepidermisandcausingarawlineararea(i.e.,deepscratch);oftenself-inflicted
LichenificationThickened,roughskin(similartoalichenonarock);usuallytheresultofrepeatedrubbing
Macule,patchCircumscribed,flatlesiondistinguishedfromsurroundingskinbycolor.Maculesare5mmindiameterorless,whilepatchesaregreaterthan5mminsize.
Papule,noduleElevateddome-shapedorflat-toppedlesion.Papulesare5mmindiameterorless,whilenodulesaregreaterthan5mminsize.
PlaqueElevatedflat-toppedlesion,usuallygreaterthan5mmindiameter(maybeformedbycoalescenceofpapules)
PustuleDiscrete,pus-filled,raisedlesion
ScaleDry,horny,platelikeexcrescence;usuallytheresultofimperfectcornification
Vesicle,bulla,blisterFluid-filledraisedlesion5mmorlessindiameter(vesicle)orgreaterthan5mmindiameter(bulla).Blister isthecommontermforbothlesions.
WhealItchy,transient,elevatedlesionwithvariableblanchinganderythemaformedastheresultofdermaledema
DyskeratosisAbnormal,prematurekeratinizationwithincellsbelowthestratumgranulosum
HyperkeratosisThickeningofthestratumcorneum,oftenassociatedwithaqualitativeabnormalityofthekeratin
ParakeratosisRetentionofnucleiinthestratumcorneumofasquamousepithelium.Onmucousmembranes,parakeratosisisnormal.
immunoglobulin E (IgE) antibodies attached to the mast cell surface through their Fc receptor. Responsible antigens include viruses, pollens, foods, drugs, and insect venom. IgE-independent urticaria also can result from exposure to substances that directly incite mast cell degranulation, such as opiates and certain antibiotics. In the vast majority of cases, no clinical cause is discovered even with extensive investigation.
MORPHOLOGYThehistologicfeaturesofurticariaoftenaresubtle.Thereisusuallyasparsesuperficialperivenularinfiltrateofmononuclearcells,rareneutrophils,andsometimeseosinophils.Superficialdermaledemacausessplayingofcollagenbundles,makingthemappeartobemorewidelyspacedthannormal.Degranulationofmastcells,whichresidearoundsuperficialdermalvenules,isdifficulttoappreciatewithroutinehematoxylin-eosin(H&E)stainsbutcanbehighlightedusingaGiemsastain.
Urticaria typically affects individuals between 20 and 40 years of age, but no age is immune. Individual lesions usually develop and fade within hours, but episodes can persist for days or even months. Lesions range in size and nature from small, pruritic papules to large, edematous, erythematous plaques. They may be localized to a particular part of the body or generalized. In a specific type of urticaria termed pressure urticaria, lesions are found only in areas exposed to pressure (such as the feet or buttocks). Although not life-threatening, severe pruritus and the social embarrassment of urticaria can compromise quality of life. Most cases respond to antihistamines, but more severe, refractory disease may require treatment with leukotriene antagonists, monoclonal antibodies that block the action of IgE, or immunosuppressive drugs.