The authors characterized the clinical features of patients with direct immunofluorescence (DIF)-negative mucous membrane pemphigoid (MMP).
This retrospective case series comprised 36 patients who underwent conjunctival biopsy for suspected MMP; 32 had a negative DIF on initial biopsy. Outcomes of the study included visual acuity, Foster stages, extraocular muscle involvement, history of autoimmune disease and duration of follow-up.
Of the 32 patients with negative DIF, 2 had a positive DIF on repeat biopsy. Eleven patients had progression of conjunctival scarring during the median follow-up of 42 months and were diagnosed with biopsy-negative MMP.
An additional 11 patients were diagnosed with other causes of cicatrizing conjunctivitis. When compared with cicatrizing conjunctivitis of other causes, biopsy-positive and biopsy-negative MMP had significantly lower visual acuity at presentation and higher conjunctival scarring score.
The sample size in this study is relatively small, and there may be a selection bias as all patients had been referred to a major academic center for evaluation and treatment.
Causes of cicatrizing conjunctivitis are diverse and include chemical injury, infection (trachoma, Corynebacterium diphtheriae conjunctivitis, streptococcal conjunctivitis), inflammatory disorders (ocular rosacea, Sjogren syndrome, atopic keratoconjunctivitis, graft-vs-host disease, drug induced conjunctivitis), autoimmune disorders (MMP, lichen planus), malignancy and allergic reactions (Stevens-Johnson syndrome).
Conjunctival biopsy, which includes light microscopy, DIF and electron microscopy, is crucial to diagnose the exact underlying cause of cicatrizing conjunctivitis. Those patients with progressive cicatricial changes with a negative biopsy for MMP should be treated as patients with positive biopsies for MMP; this is an important factor to consider when oculoplastic surgeons perform surgery on these patients.