I have a weird itchy rash on my torso and neck that started 3 weeks into keto. It's red and slightly raised in a net-like pattern. Went to the dermatologist and she called it "prurigo pigmentosa" and said it's associated with ketosis. Is this really a keto thing? How long does it last?
Yes, keto rash (prurigo pigmentosa) is a real documented dermatological reaction that occurs specifically in ketosis — it's actually used diagnostically in some cases. The exact mechanism isn't fully understood but it's thought to be a reaction to ketones being excreted through sweat on the skin.
Good news: It's completely benign — no systemic implications, just uncomfortable.
Treatment options that work:
1. Slightly increase carb intake to 30-50g — often resolves the rash while keeping you in mild ketosis
2. Antibiotics (doxycycline or minocycline) — prescribed by dermatologists, clears it rapidly
3. Improve ventilation/reduce sweating in affected areas
4. Some people find MCT oil reduction helps as it increases ketone production and sweating
I had this for about 3 weeks at the start of my second keto attempt. Bumped carbs to 35g for 2 weeks, rash resolved, then went back to 20g without it returning. The temporary carb increase seems to clear whatever triggers it and then full ketosis is tolerated fine afterward.
My derm prescribed doxycycline for 2 weeks and it cleared completely within 5 days. Continued keto through the entire treatment with no issues. The antibiotic route is fast if you want to stay strictly ketogenic and don't want to modify your carbs.
Thank you — I didn't know bumping to 35g temporarily was an option. Going to try that before antibiotics since it's less invasive. Will report back in 2 weeks.