Background: Familial bullous lichen planus (FBLP) is a rare condition. The clinical features dearly have been described.
Objective: We report the largest patient series of FBLP and describe its clinical characteristics and inheritance pattern.
Methods: In this retrospective chart review, we analyzed nine consecutive familial pedigrees of FBLP with 36 affected individuals who presented to the Department of Dermatology at the Wuhan Union Hospital, a tertiary referral hospital in central China. Parameters analyzed include age of onset, gender predilection, lesional distribution, nail and mucosal involvement, clinical course, and inheritance pattern.
Results: Thirty-six of 85 individuals in the nine families were affected (42.4%). Females were more likely to be affected than males (58.3% vs 35.7%, G(chi 2 = 3.99. P < 0.05). A bimodal disease onset was found, with one peak at 1-3 years and another at 13-17 years. The shin is the most commonly affected area (97%) followed by the upper limbs and the thighs. Involvement of the torso is relatively rare. Only a minority of cases involves the oral mucosa. The disease tends to follow a chronic and progressive course. The inheritance pattern is autosomal dominant with variable penetrance.
Conclusion: Familial bullous lichen planus is a chronic, progressive bullous eruption of the lower and upper extremities. Compared with non familial bullous lichen planus, it has an earlier onset and wider disease distribution. It may be inherited as an autosomal dominant condition with variable penetrance.