A weird, itchy rash is linked to the keto diet

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A 20-year old man in Taiwan went to a dermatology clinic for a strange rash that had developed across his shoulders and chest. The raised, red, and itchy condition had been bothering him for a full month. By this point, he had also developed patches of pigmented skin interlaced with the red rash.

In the man’s case, doctors gave him a two-week course of doxycycline and told him to ditch his keto diet. A week later, the rash was gone.

Full story here at Arstechnica

And the case report

Prurigo Pigmentosa, 2026, Lee et al

Lee, Chin-Yu; Hu, Stephen Chu-Sung

Abstract
A 20-year-old man presented with an itchy rash 2 months after starting a ketogenic diet. Examination showed symmetric, erythematous papules and underlying reticulated hyperpigmentation on the chest, neck, and shoulders.

Web | DOI | New England Journal of Medicine | Paywall