Case Presentation: An 11-year-old obese male of Micronesian descent presented with a pruritic bullous rash and bilateral lower extremity pain. Scattered non-blanching purpura started on both ankles 10 days prior and spread to his legs, back and arms accompanied by bilateral leg pain and intense pruritus. Four days prior to presentation, blisters to legs and abdomen developed overlying some of the previous rash. He had no respiratory, gastrointestinal or urinary symptoms and took occasional ibuprofen for leg pain. On admission, he was febrile to 39.0 °C with otherwise normal vital signs. Bullae on the legs were filled with serosanguineous fluid and ranged in size from 5 mm to 1 cm predominantly on the lower legs, and to a lesser degree on arms and trunk (see figure 1). He was found to have elevated inflammatory markers and positive streptococcal studies. Renal and hepatic tests were normal. He was started on intravenous cefazolin and cultured fluid from a bulla grew pansensitive streptococcus pyogenes. Fevers resolved promptly and leg pain, pruritus and rash steadily improved over the next few days. Skin biopsy was consistent with IgA vasculitis. Proteinuria resolved promptly, but microscopic hematuria persisted for two months.
Discussion: The differential for bullous lesions is broad. Tense blisters occur with subepidermal skin disintegration, which includes bullous pemphigoid, linear IgA dermatosis, epidermolysis bullosa, porphyria cutanea tarda, toxic epidermal necrolysis, bullous drug reactions, erythema multiforme, IgA vasculitis (IgAV), bullous lupus erythematosus and dermatitis herpetiformis1. Our patient’s presentation with gravity-dependent palpable purpura, arthralgia and glomerulonephritis is consistent with IgAV despite the absence of gastrointestinal symptoms. While IgA vasculitis is a clinical diagnosis, a skin biopsy is helpful in unclear cases. Only 2 % of pediatric patients with IgAV develop bullous lesions contrasted with up to 60 % in adults. Presence of bullous lesions does not appear to have prognostic value. Streptococcus pyogenes is likely a trigger for IgAV2, 3.
Conclusions: IgAV classically presents with palpable purpura, gastrointestinal symptoms, arthralgia and renal disease, but presentation is highly variable. Bullous lesions in pediatric IgAV are rare, however should be recognized as an atypical skin manifestation of IgAV. Presence of bullous lesions does not seem to have prognostic value. Skin biopsy is helpful in patients with bullous lesions, especially if the classic pentad of IgA vasculitis is not present.