增殖性化脓性口炎是一种罕见的炎症性黏膜病，通常与炎症性肠病密切相关。IgA天疱疮是一种临床上较为少见的自身免疫性大疱性疾病，较少累及黏膜组织。本文报道1例以增殖性化脓性口炎为首发症状的IgA天疱疮病例，该病例后续出现耳后、颈部、背部和肛周脓疱，以及消化道症状、同行反应等临床表现。经糖皮质激素、沙利度胺和利妥昔单克隆抗体等联合治疗后，患者症状改善，该病例的广泛黏膜受累表现为深入认识IgA天疱疮提供了新的参考依据。本病例提示增殖性化脓性口炎可作为IgA天疱疮的首发表现，临床中需将IgA天疱疮纳入其鉴别诊断，多学科诊治有助于明确诊断。

Pyostomatitis vegetans (PSV) is an uncommon inflammatory disorder of the oral mucosa, frequently associated with inflammatory bowel disease. IgA pemphigus, a rare autoimmune bullous disease, seldom involves mucosal tissues. We present a case of IgA pemphigus initially manifesting as PSV, with subsequent development of pustular lesions on the posterior trunk, neck, back, and perianal region, accompanied by gastrointestinal symptoms and peer reactions. The patient's condition improved following combination therapy with glucocorticoids, thalidomide, and rituximab. The extensive mucosal involvement observed in this case broadens the understanding of the clinical spectrum of IgA pemphigus. This report highlights that PSV may serve as an initial manifestation of IgA pemphigus, which should therefore be considered in the differential diagnosis of such oral lesions. Multidisciplinary management is essential for accurate diagnosis and effective treatment.