Nutrition and the skin — SAQ

Stem

A 32-year-old woman with heavy alcohol use presents with a photosensitive, well-demarcated rash on the dorsal hands and a V-shaped neck rash, diarrhoea, and confusion. Separately, a premature infant on total parenteral nutrition develops periorificial dermatitis despite zinc already being in the feed, and an adult dialysis patient has a follicular rash whose biopsy shows corkscrew hairs.^[21][30][36]

Questions

a) What is the most likely diagnosis for the first patient, and which classical tetrad supports it? (2 marks)

^{[19] [20]}

b) What investigations and differentials would you consider, and why may diagnosis be delayed? (3 marks)

^{[20] [27] [34]}

c) Outline sourced replacement for pellagra, zinc-deficiency dermatitis, and biopsy-proven scurvy. (3 marks)

^{[21] [29] [36]}

d) What complications and nutritional-rehabilitation caveats should the examiner hear? (2 marks)

^{[20] [25] [30]}

Model answer (must-hit points)

a) Pellagra from niacin deficiency (or disrupted niacin metabolism). Mousa: Casal described the disease; it is characterised by dermatitis, diarrhoea, dementia, and eventually death if not treated with niacin — the 4 Ds. Diarrhoea and dementia may not always be present. Hołubiec: photosensitive dermatitis plus gastrointestinal and neuropsychiatric features. Secondary pellagra tracks chronic alcohol use, malabsorption, immunosuppressive and anti-tuberculosis drugs, and bariatric surgery.^[19][20][21]

b) Pellagra is diagnosed primarily on the clinical picture; auxiliary tests play a secondary role, and unfamiliarity delays treatment (Hołubiec). For the infant, consider inherited or acquired acrodermatitis enteropathica, including a bullous variant if diagnosis is delayed (Iyengar). For oedema plus desquamation in a restricted-diet child, include kwashiorkor rather than isolated atopic dermatitis (Xavier). Zinc 36 mcg/dL confirmed deficiency in Changela's adult AE-pattern case on apparently adequate enteral nutrition.^{[20][27][34][29]}

c) Pellagra: causal niacinamide; Hassan used niacin 500 mg once daily until lesions resolved (with topical betamethasone plus salicylic acid in that case). Zinc-deficiency dermatitis: oral zinc; Changela used zinc sulfate 220 mg 3 times a day with rapid resolution. Scurvy with corkscrew hairs: El Khoury used ascorbic acid 500 mg twice daily for 2 weeks with complete rash resolution.^[21][29][36]

d) Untreated pellagra leads to death. Premature TPN infants may develop periorificial dermatitis even after 146 to 195 percent of 400 microg/kg/day zinc; they needed increased supplementation for 6 to 18 days. Severe acute malnutrition is treated with WHO F-75 then F-100 recipes that remain feasible in small district hospitals; SAM death risk is 9 times that of well-nourished children and hospitalised SAM death rates have been as high as 15 percent. Unsourced NICE/Pabrinex milligram refeeding recipes are not required here.^[20][30][25]

References9ShowHide

1. [19]Mousa TY, Mousa OY. Nicotinic Acid Deficiency StatPearls, 2026.PMID 32491681
2. [20]Hołubiec P, Leończyk M, Staszewski F, et al. Pathophysiology and clinical management of pellagra - a review Folia Med Cracov, 2021.PMID 34882669
3. [21]Hassan HS, Pandu SM, Said SS. Pellagra in Zanzibar: a rare diagnosis Int J Dermatol, 2023.PMID 36459461
4. [25]Rashid MA, Rahman ME, Kamruzzaman M, et al. Efficacy of F-75 & F-100 Recipes in theTreatment of Severe Acute Malnutrition: A Randomized Controlled Trial Mymensingh Med J, 2019.PMID 31599256
5. [27]Iyengar S, Chambers C, Sharon VR. Bullous acrodermatitis enteropathica: case report of a unique clinical presentation and review of the literature Dermatol Online J, 2015.PMID 25933075
6. [29]Changela A, Javaiya H, Changela K, et al. Acrodermatitis enteropathica during adequate enteral nutrition JPEN J Parenter Enteral Nutr, 2012.PMID 22038206
7. [30]Barbarot S, Chantier E, Kuster A, et al. Symptomatic acquired zinc deficiency in at-risk premature infants: high dose preventive supplementation is necessary Pediatr Dermatol, 2010.PMID 20653858
8. [34]Henrique de S B Xavier M, De Magalhães E, Ferraz Oliveira G, et al. A child with kwashiorkor misdiagnosed as atopic dermatitis Dermatol Online J, 2017.PMID 28537869
9. [36]El Khoury R, Warren M, Ali S, et al. An Unexpected Case of Scurvy in a Peritoneal Dialysis Patient Case Rep Nephrol Dial, 2017.PMID 29594144