Intestinal bypass syndrome presenting as erythema nodosum.

Intestinal bypass was a popular surgical procedure for morbid obesity resulting, on average, in a 50 kg weight loss. We describe a 66-year-old woman who underwent the procedure 12 years earlier and subsequently presented with recurrent episodes of erythema nodosum-like lesions. Further investigations revealed hyperoxaluria, renal failure, deficiency of fat-soluble vitamins (causing night blindness, osteomalacia and easy bruising) and anaemia. Antibiotics led to only temporary remission and, as with 24-30% of similar cases, she underwent surgical reversal to prevent the complications from worsening.