Abstract
Linear IgA Bullous Dermatosis (LABD) is a rare autoimmune subepidermal vesiculobullous disease caused by linear deposition of IgA anti-basement membrane zone antibodies. LABD characteristically presents with annular erythematous lesions with a ring of vesicles resembling a “string of pearls”. There have been rare reports of some patients with LABD that demonstrate both IgA and IgG autoantibodies, referred to as linear IgA/IgG bullous dermatosis (LAGBD.) A 30-year-old male with history of recently diagnosed HIV on Biktarvy and untreated syphilis presented to the hospital with worsening pruritic rash and a scalp ulcer for 6 months. On exam, there were numerous erythematous and hyperpigmented papules admixed with hypopigmented-pink atrophic papules, areas of grouped vesicles noted with clear fluid, and scattered excoriated vesicles. No mucosal lesions were noted. Punch biopsy revealed subepidermal blisters with a predominately neutrophilic infiltrate on H&E. Direct immunofluorescence studies revealed a linear deposition of IgA, IgG and C3 at the dermoepidermal junction. Diagnosis of LAGBD was confirmed and patient started on dapsone. The heterogeneity in autoantigens may contribute to the variable clinical presentations and hence why our patient did not demonstrate the characteristic annular pattern. This case illustrates the potential of LABD to have a variety of clinical presentations, often mimicking other bullous or inflammatory conditions. Although the exact etiology of LABD and LABGD remains elusive in most cases, drug-induced causes must be considered. Diagnosis of this rare bullous dermatosis is established through a combination of clinical presentation, histopathological examination, and direct immunofluorescence studies.