Synonyms: Finkelstein's disease, Seidlmayer's disease, postinfectious cockade purpura
Clinical features:
(1) age of the patient is usually from 4 to 24 months
(2) recent antigenic stimulus (see below)
(3) skin lesions (see below)
(4) low-grade fever
(5) variable peripheral non-pitting edema which may be tender
(5) otherwise asymptomatic and nontoxic
(6) recovery in 6 to 21 days
(7) occasionally may involve recurrent episodes
Antigenic stimulus may include:
(1) viral infection (echovirus, enterovirus, coxsackie, rhinovirus, etc)
(2) mycoplasma infection
(3) bacterial infection
(4) vaccination
(5) drug therapy
Skin lesions:
(1) tend to involve the face and extremities while sparing the trunk
(2) may be erythematous macules, papules or plaques, urticaria, purpura, targetoid lesions
Laboratory findings:
(1) variable leukocytosis, usually mild if present
(2) variable elevation ESR and C-reactive protein
(3) normal serum IgA
A biopsy shows leukocytoclastic vasculitis. Immunofluorescence usually shows C1q deposition but is negative for IgA deposits.
Differential diagnosis:
(1) Henoch Schonlein purpura
(2) erythema multiforme
(3) fixed drug eruption
(4) meningococcemia
(5) Sweet's syndrome
(6) urticarial vasculitis
