Keto Diet Linked to Rare Rash, While New Test Offers Hope for Crohn's Detection

A rare skin condition has been linked to the ketogenic diet, while a separate development offers a potential breakthrough in early Crohn's disease detection. A case study documented a 20-year-old man in Taiwan who developed a strange, itchy rash across his shoulders and chest after starting the diet, according to a report in the New England Journal of Medicine. Simultaneously, a novel blood test is showing promise in earlier detection of Crohn's disease by identifying immune responses to gut bacteria, potentially leading to improved treatment outcomes.

The man sought treatment at a dermatology clinic after the raised, red, and itchy condition persisted for a month. The rash was accompanied by patches of pigmented skin. A skin biopsy revealed swelling between skin cells and inflammation around blood vessels, but tests for common skin conditions came back negative. Doctors ultimately linked the condition to his dietary history, highlighting the importance of considering diet in dermatological diagnoses.

In related news, researchers are focusing on Crohn's disease. A new blood test identifies immune responses to gut bacteria, potentially enabling earlier interventions and improved outcomes. This development could significantly improve the management of Crohn's disease through earlier diagnosis.

Separately, research from Weill Cornell Medicine published on January 25, 2026, has uncovered an immune chain reaction in the gut that may explain why people with inflammatory bowel disease face a higher risk of colorectal cancer. The study found that an inflammatory signal activates specialized gut immune cells, which then recruit white blood cells from the bone marrow and rewire them in ways that promote tumor growth. This process appears to damage DNA in the gut lining and create a tumor-friendly environment.