A Potential Link between Amyotrophic Lateral Sclerosis and Bullous Pemphigoid: Six New Cases and a Systematic Review of the Literature.

Objective Bullous pemphigoid in amyotrophic lateral sclerosis (BP-ALS) is rare and poorly understood. We herein assessed the association between ALS and BP using clinical and biological findings. Methods The clinical features of six new BP-ALS cases were described and collated with cases from a systematic literature review. Results Our six cases were combined with three other published cases. The mean disease duration (from ALS onset to the occurrence of BP) was 5.6±3.1 years. All patients had limb-onset ALS. Four of the 9 patients received riluzole, with the use of riluzole ranging from a few days to 3 years. When BP occurred, the status of the ALS patients was paretic and/or bedridden in all cases. BP occurred throughout the body, and we confirmed that the bullous lesions were located not only at the compression site, but also at the anterior part of the chest, abdomen, and limbs. Treatment for BP was successful, as oral prednisone and/or local corticosteroids were effective in 8 cases. Conclusion These six new cases, in combination with previous cases, expand our knowledge of the relationship between dermatological lesions and ALS. The pathogenesis of BP-ALS is poorly understood, however, some immunological aberrance is likely.