Eruptive pseudo-angiomatosis lesions are associated with intravascular neutrophils and do not harbour Epstein-Barr...

Eruptive pseudo-angiomatosis (EPA) is a rare, relatively newly described cutaneous disorder characterized by the sudden onset of several bright red, angioma-like papules surrounded by blanched halo. Its aetiology is unknown; however, viral infection or mosquito bites have been speculated as possible causes.

This study aims to determine the clinical and histopathological features of EPA, and whether it is associated with Epstein-Barr virus (EBV) infection.

We conducted a retrospective chart review of 25 EPA cases from 2006 to 2008. In order to determine latent EBV infection, EBV-encoded small RNA (EBER) in situ hybridization was performed in 18 subjects. To determine EPA's distinguishing histological characteristics, we compared the cases with 22 control cases of perivascular lymphocytic infiltration for haematoxylin and eosin, CD3, CD4, CD8, CD31 and c-kit staining patterns.

The patient sample's female-to-male ratio was 2.1 : 1, and the patients' age ranged from 5 to 79 years (average 46 years). The lesions appeared during the months of July to September in all but 3 patients. Skin biopsies demonstrated capillary ectasia with perivascular mononuclear cellular infiltrates in the upper dermis. Most patients were otherwise healthy, and routine laboratory results were all normal except in one patient who had diabetes. The skin lesions faded without any treatment in 1-2 weeks. Results of EBER in situ hybridization were all negative. The only histological distinguishing feature of EPA was the presence of intravascular neutrophils, which was found to be present in 19 of the 20 EPA cases (95%), in contrast to only 3 of the 22 control subjects (14%) (P < 0.0001).

The sudden onset of lesions during the summer months among our patients supports the 'paraviral eruption' concept of this probably underdiagnosed condition. The significant presence of intravascular neutrophils may be a diagnostic clue of EPA in South Korea.