This 19-year-old man developed a generalized pruritic pustular eruption several days after an upper respiratory infection, for which he received antibiotics. The etiology of acute generalized exanthematous pustulosis (AGEP) is unknown, but viral illnesses and drugs have been implicated. Patients develop numerous pruritic sterile pustules on an erythematous base. The histopathology in this case is typical, showing combined spongiotic dermatitis with pustule formation. The histologic differential diagnosis would include other causes of eczematous dermatitis as well as infections, such as tinea. Other considerations would be the subcorneal pustular dermatoses, which includes infections and pustular psoriasis, among others.
This higher power field shows epidermal spongiosis with exocytosis of neutrophils and eosinophils. Small microvesicles/microabscesses are developing. In other fields (not shown), there is subcorneal pustule formation. Special stains for bacteria and fungi were negative (not shown).