Q: How to proceed A: The clinical picture is very clear. Here is a full structured assessment: --- Clinical Assessment: Pellagra Niacin/Vitamin B3 Deficiency What You're Looking At The images show bilateral, symmetrical, hyperkeratotic, crusted plaques with central erosions on the dorsal surfaces of both feet and ankles - a classic sun-exposed distribution. The lesions are sharply demarcated, have a copper-mahogany hue, and show central exudation/crusting with peripheral scaling. The setting rural India, agricultural worker, barefoot strongly supports a nutritional etiology. This is pellagra - the textbook presentation. Compare with the Fitzpatrick's dermatology image above showing nearly identical lesions on forearms and neck. --- Diagnosis: Pellagra The "4 Ds" of Pellagra - assess each: Feature Status in This Patient ------ Dermatitis YES - bilateral photodistributed plaques on dorsal feet sun-exposed Diarrhea Ask the patient Dementia/cognitive changes Ask the patient Death if untreated Preventable with treatment Why bilateral dorsal feet? This patient walks barefoot in the field - the dorsum of the feet is the maximally sun-exposed surface in a squatting/walking agricultural worker. This is the foot equivalent of "Casal's necklace" the classic neck distribution. --- Etiology in This Context This is a rural Indian agricultural worker - the most likely cause is: - Corn/maize or sorghum/jowar-dominant diet with inadequate animal protein, dairy, or legumes - These grains are high in bound niacin niacin bound to niacytin, which is bioavailable only if treated with lime nixtamalization - not traditional in India - Tryptophan niacin precursor is also low in these diets Other causes to ask about: - Isoniazid or anti-TB drugs very important to rule out - INH is a common iatrogenic cause in India - Alcohol use - Chronic diarrhea/malabsorption --- How to Proceed: Management 1. Confirm the Diagnosis Clinically - Ask about diet corn/jowar/maize-heavy? - Ask about diarrhea, confusion, weakness - Ask about TB treatment isoniazid use? - No lab tests are strictly necessary - the clinical picture is diagnostic 2. Treatment Andrews' Dermatology Nicotinamide preferred over nicotinic acid - no flushing: 100 mg orally, three times daily for several weeks - Nicotinamide = niacinamide is available OTC in India as vitamin B3 tablets - Response is rapid - skin lesions begin resolving within 24-48 hours, confirming the diagnosis - Continue for 3-4 weeks minimum Supportive measures: - Replace fluid/electrolyte losses if diarrhea present - If significant GI involvement prevents oral absorption: IV or IM supplementation initially - Give a B-complex supplement simultaneously multiple B-vitamin deficiencies coexist - High-protein diet: eggs, milk, pulses dals, groundnuts, meat/fish if available 3. Dietary Counseling - Increase dietary niacin: groundnuts, legumes, eggs, milk, meat, fish - Diversify away from corn/sorghum-only diet - Avoid going barefoot in direct sun while healing 4. Sun Protection - Cover feet and legs while outdoors during treatment - Chappals/sandals or socks to prevent further UV-induced phototoxic damage 5. If on Isoniazid TB drugs - Add pyridoxine vitamin B6 50 mg/day AND nicotinamide supplementation - Do NOT stop anti-TB treatment - manage with supplementation --- What NOT to Do - Do not apply topical steroids will not help pellagra; may delay diagnosis - Do not treat as tinea/fungal without ruling out pellagra first - Do not use nicotinic acid plain niacin if avoidable - causes flushing; nicotinamide is better tolerated --- Expected Outcome With nicotinamide 100 mg TDS, improvement begins within 24-48 hours. Skin clears significantly over 2-4 weeks. Prognosis is excellent if underlying dietary cause is corrected. Without treatment, pellagra is progressive and potentially fatal coma/death from the 4th D. Sources: Andrews' Diseases of the Skin, Fitzpatrick's Dermatology Vol 1-2 Note: This is a clinical assessment based on images. A clinician should examine the patient directly, assess for GI and neurological symptoms, and confirm medication history before finalizing management.
