Wenjuan Chen,1,2 Chen Peng,1,2 Jianfeng Zheng,1,2 Xiya Lu,1,2 Yangfeng Ding,1,2 Lina Su1,2 1Department of Dermatology, Shanghai Skin Disease Hospital, Tongji University School of Medicine, Shanghai, People’s Republic of China; 2Institute of Psoriasis, Tongji University School of Medicine, Shanghai, People’s Republic of ChinaCorrespondence: Lina Su; Yangfeng Ding, Department of Dermatology, Shanghai Skin Disease Hospital, Tongji University School of Medicine, 1278 Baode Road, Jing’an District, Shanghai, 200443, People’s Republic of China, Email sulina11@hotmail.com; vygd112@163.comAbstract: Psoriasis is an immune-mediated systemic disease with multiple organs involvement, such as cardiovascular, live, gut, endocrine, and so on. Bullous pemphigoid (BP) is a rare comorbidity associated with psoriasis, while BP occurring in erythrodermic psoriasis (EP) is very rare. In this case, we reported a woman with severe EP who developed BP, in whom beta hemolytic streptococcus infection was a possible triggering factor. The complicated condition of such patients needs to draw attention of the physician and study further for better treatment.Keywords: bullous pemphigoid, erythrodermic psoriasis, comorbidity