Direct immunofluorescence is of limited utility in patients with low clinical suspicion for an oral autoimmune bullous disorder.

Objectives Oral autoimmune bullous disorders show clinical overlap with diseases such as lichen planus and others that may cause desquamative gingivitis. As direct immunofluorescence is expensive, we sought to determine if routine histology alone would be sufficient to distinguish between oral autoimmune bullous disorders and mimics. Methods We searched the records for patients with a suspected oral autoimmune bullous disorder who underwent biopsies for concurrent routine histologic evaluation and direct immunofluorescence and who had at least one follow-up visit. Cases were separated into high and low suspicion subgroups based on clinical findings. Results Within 148 cases, the sensitivity of routine histology alone was 0.810, with a negative predictive value of 0.889. However, the specificity was 0.989 with a positive predictive value of 0.979. Of the high suspicion cases, 57 (47.1%) were found to be consistent with an oral autoimmune bullous disorder, with a total of 11 histologic false negatives. 8 cases, all in the high suspicion subgroup, showed indeterminate direct immunofluorescence results. There were no histologic false negatives or inconclusive direct immunofluorescence results in the low suspicion subgroup. Conclusions In patients with a low clinical suspicion for an oral autoimmune bullous disorder, it is reasonable and more cost-effective to evaluate the lesion with routine histology alone.