Linear IgA disease histopathologically and clinically masquerading as lichen planus.

In each of 2 cases reported, the patient presented with features of erosive lichen planus or lichenoid drug eruptions and an incisional biopsy taken from the patient was diagnosed histologically as lichen planus. Subsequent recurrences or exacerbations were associated with vesiculobullous lesions. Simultaneous or subsequent direct immunofluorescence studies--from the same tissue sample in one case and from a similar site in the other case--demonstrated classic features of linear IgA disease. Both patients were originally treated for lichen planus with systemic and/or topical corticosteroids with limited success. One patient was treated with sulfapyridine with minimal improvement. Both patients were subsequently treated with dapsone and demonstrated significant clinical improvement. We propose that linear IgA disease may be more common than reported in the oral cavity, inasmuch as many cases of recalcitrant lichen planus, erosive lichen planus, and lichenoid drug eruptions, especially those with a vesiculobullous component, may in reality represent linear IgA disease. We recommend that direct immunofluorescence be done in any case in which bullous lichen planus is suspected.