Bowel-associated dermatosis–arthritis syndrome (BADAS), is a complication of jejunoileal bypass surgery consisting of flu-like symptoms (fever, malaise), multiple painful joints (polyarthralgia), muscle aches (myalgia) and skin changes.

Antibiotics have been used successfully to treat the condition (including tetracyclines, macrolides, metronidazole and fluoroquinolones).

[citation needed] BADAS has later been reported in patients with inflammatory bowel disease,[1] diverticulitis[2] and following resection of the stomach (gastrectomy).

[1] The most typical skin changes are a red patch (erythematous macula) with a central vesicle or pustule that heals without scarring.

[5] Immune complexes are thought to cause blood vessel damage, attracting neutrophils into the skin and synovium in BADAS.