Irritable bowel syndrome‐like disorders in endometriosis: prevalence of nickel sensitivity and effects of a low‐nickel diet. An open‐label pilot study

Alimentary nickel (Ni) may result in allergic contact mucositis (ACM), whose prevalence is >30% and may present with IBS‐like and extra‐intestinal symptoms. These symptoms are also frequent in endometriosis, and Ni allergic contact dermatitis has already been observed in endometriosis. Therefore, intestinal and extra‐intestinal symptoms in endometriosis may depend on a Ni ACM, and a low‐Ni diet could improve symptoms. We studied the prevalence of Ni ACM in endometriosis and focused on the effects of a low‐Ni diet on gastrointestinal, extra‐intestinal, and gynecological symptoms. We recruited 84 women with endometriosis, symptomatic for gastrointestinal disorders. Thirty‐one out of 84 patients completed the study. They underwent Ni oral mucosa patch test (omPT), questionnaire for intestinal/extra‐intestinal/gynecological symptoms, and a low‐Ni diet. Clinical evaluation was performed at baseline (T0) and after three months (T1). Twenty‐eight out 31 (90.3%) patients showed Ni omPT positive results, with Ni ACM diagnosis, whereas three out of 31 (9.7%) patients showed negative Ni omPT. After three months of low‐Ni diet, all gastrointestinal, extra‐intestinal and gynecological symptoms showed a statistically significant reduction. Ni ACM has a high prevalence in endometriosis and a low‐Ni diet may be recommended in this condition to reduce gastrointestinal, extra‐intestinal and gynecological symptoms.