Adult‐onset linear IgA bullous dermatosis: a retrospective single‐center cohort study of 81 patients and literature review

BACKGROUND: Linear IgA bullous dermatosis (LABD) is a rare autoimmune blistering disorder that may be drug-induced or paraneoplastic. We aim to characterize features of LABD and determine differentiating factors among idiopathic, drug-induced, or malignancy-associated diseases. METHODS: We conducted a single-center retrospective chart review of adult patients with linear IgA bullous dermatosis at a large tertiary referral center and a literature review of adult linear IgA bullous dermatosis. RESULTS: Eighty-one patients were included in the study. Ten patients (12.3%) had comorbid malignancy and nine (11.1%) had inflammatory bowel disease. Median disease duration was significantly shorter in both drug-induced (1.2 vs. 48.8 months; P < 0.001) and malignancy-associated (1.7 vs. 48.8 months; P < 0.001) LABD compared with idiopathic LABD. Recurrent episodes occurred significantly more often in idiopathic LABD compared to those with drug-induced (76.1 vs. 11.5%; P < 0.001) or malignancy-associated disease (76.1 vs. 33.3%; P = 0.019). Time to diagnosis was significantly shorter in the drug-induced (0.2 vs. 5.4 months; P < 0.001) and malignancy-associated groups (0.7 vs. 5.4 months; P = 0.049) compared with idiopathic; similarly, time to improvement was significantly shorter in both drug-induced (0.4 vs. 3.0 months; P < 0.001) and malignancy-associated disease (1.1 vs. 3.0 months; P = 0.016). Clinical morphology was indistinguishable between groups. Limitations included retrospective data collection, data from tertiary referral centers, and limited racial and ethnic diversity. CONCLUSION: Screening for underlying malignancy, as well as for a predisposing medication or possibly inflammatory bowel disease, may be advisable in patients with LABD, particularly when it is newly diagnosed.