Background Eruptive pseudoangiomatosis (EP) is a rare, benign, spontaneously regressing exanthema of unknown etiology, characterized by an eruption of distinctive erythematous papules. This study was performed to evaluate the etiologic, clinical, and histopathologic characteristics of EP in Koreans.
Methods Patients diagnosed with EP during 2005–2010 were included in a retrospective study. Diagnoses were based on clinical findings and confirmed by histology. Biopsies were re-examined. Patient gender, age at onset, disease duration, lesion location, season of occurrence, concomitant diseases, occupation, previous related events, disease course, responses to treatment, and laboratory findings were analyzed.
Results A total of 32 patients were identified. Mean age at onset was 50.06 ± 17.12 years. Two patients developed lesions after outdoor activities. Two patients presented with simultaneous occurrences in family members. One patient reported having taken herbal medicine. One subject experienced systemic contact dermatitis caused by eating a lacquer chicken dish just before the lesions developed. All patients had typical erythematous papules measuring 2–5 mm. Lesions were usually located on exposed sites. No prodromal or systemic symptoms were observed. Routine laboratory tests were within normal ranges, except in one patient with known hyperlipidemia. Most patients were treated with oral antihistamine and topical steroid, or oral prednisolone. Eight patients did not receive any treatment. Mean disease duration was 1.64 ± 1.41 months in the treatment group and 1.20 ± 1.24 months in the no-treatment group (P > 0.05).
Conclusions Any clear relationship between EP and exposure to allergens or insect bites has yet to be elucidated. In patients in whom EP occurs on non-exposed sites, drugs and food should be considered as possible causative agents. Intravascular neutrophil infiltration on histology can be helpful in diagnosing EP.