Signs and symptoms
Contagious impetigo
This most common form of impetigo, also called nonbullous impetigo, most often begins as a red sore near the nose or mouth which soon breaks, leaking pus or fluid, and forms a honey-colored scab, followed by a red mark which often heals without leaving a scar. Sores are not painful, but they may be itchy. Lymph nodes in the affected area may be swollen, but fever is rare. Touching or scratching the sores may easily spread the infection to other parts of the body.Skin ulcers with redness and scarring also may result from scratching or abrading the skin. Bullous impetigo
Bullous impetigo, mainly seen in children younger than 2 years, involves painless, fluid-filled blisters, mostly on the arms, legs, and trunk, surrounded by red and itchy (but not sore) skin. The blisters may be large or small. After they break, they form yellow scabs. Ecthyma
Ecthyma, the nonbullous form of impetigo, produces painful fluid- or pus-filled sores with redness of skin, usually on the arms and legs, become ulcers that penetrate deeper into the dermis. After they break open, they form hard, thick, gray-yellow scabs, which sometimes leave scars. Ecthyma may be accompanied by swollen lymph nodes in the affected area. Causes
Impetigo is primarily caused by Staphylococcus aureus, and sometimes by Streptococcus pyogenes. Both bullous and nonbullous are primarily caused by S. aureus, with Streptococcus also commonly being involved in the nonbullous form. Predisposing factors
Impetigo is more likely to infect children ages 2–5, especially those that attend school or day care.
Prognosis
Without treatment, individuals with impetigo typically get better within three weeks. Complications may include cellulitis or poststreptococcal glomerulonephritis. Rheumatic fever does not appear to be related. Epidemiology
Globally, impetigo affects more than 162 million children in low- to middle-income countries. The rates are highest in countries with low available resources and is especially prevalent in the region of Oceania. The tropical climate and high population in lower socioeconomic regions contribute to these high rates. Children under the age of 4 in the United Kingdom are 2.8% more likely than average to contract impetigo; this decreases to 1.6% for children up to 15 years old. As age increases, the rate of impetigo declines, but all ages are still susceptible. History
Impetigo was originally described and differentiated by William Tilbury Fox around 1864. The word impetigo is the generic Latin word for skin eruption, and it stems from the verb impetere to attack (as in impetus). Before the discovery of antibiotics, the disease was treated with an application of the antiseptic gentian violet, which was an effective treatment. References
External links
Impetigo at Curlie
Impetigo and Ecthyma at Merck Manual of Diagnosis and Therapy Professional Edition