Abstract: LUO Su-ju, LI Yan, ZHOU Zhi-hai, LIU Quan-zhong. Department of Dermatology, Tianjin Medical University General Hospital，Tianjin 300052, China Corresponding author: LIU Quan-zhong, Email: quanzhongliu2008@163.com 【Abstract】 A 58-year-old female was admitted to the hospital for a 3-month history of erythema, pustules and vegetating plaques on the lips and scalp, as well as in intertriginous areas. She had a 2-year history of ulcerative colitis, which had been aggravated before the development of skin lesions. Skin examination demonstrated diffuse thickening of both lips covered with multiple granule- to mung bean-sized confluent pustules. Yellow crusts were observed at the lip margins. A 1.5 cm × 2 cm vegetating plaque surrounded by anular pustules was found in the left buccal mucosa. There were multiple irregularly-sized vegetating plaques with erosions and yellow crusts on the scalp, neck, as well as in the periumbilical and left inguinal and axillary region, and annular vesicles and pustules were observed in the center and margin of these plaques. The lesions subsided leaving hyperpigmented macules. There were four fresh pustules in the right axillary region. Histological examination of a biopsy specimen taken from the lower lip margin revealed mild hyperplasia of and neutrophil microabscess in the epidermis, as well as a dense inflammatory infiltrate composed mostly of neutrophils and eosinophils with microabscess formation in the dermis. Direct immunofluorescence examination of the normal-appearing skin next to the lesions was negative. The percentage of peripheral blood eosinophil was slightly elevated. Bacterial and fungal cultures of pustular contents were negative. A diagnosis of pyodermatitis-pyostomatitis vegetans was made. 【Key words】 Pyodermatitis-pyostomatitis vegetans