October 2023 Case Study – Derm In-Review

October 2023 Case Study

Author: Alexis E. Carrington, MD
Reviewed by Karl Saardi, MD

A 94 year old male with a medical history of CKD aphasia related a stroke presents to the clinic for a rash on the hands, face and abdomen. History of the rash is significantly limited due to his aphasia. Chart review showed that he was prescribed fluocinonide ointment for suspected atopic dermatitis with no improvement. The patient lives in a skilled nursing facility. Labs showed chronic normocytic anemia with normal folate and B12 levels and chronically elevated transaminases with AST 156 and ALT 193. On exam, there are lichenified hyperpigmented scaly plaques that are slightly photo distributed. Facial features suggestive of leonine facies. (Images 1-3).

Which of the following next steps will help diagnose the rash?

A.) Obtain serum Zinc level
B.) Obtain serum Vitamin C level
C.) Obtain flow cytometry
D.) Obtain serum Niacin levels
E.) Obtaining a mineral prep




Correct Answer: D.) Obtain serum Niacin levels


Explanation of Correct Answer:

Pellagra is a potentially fatal disease due to a lack of the vitamin niacin (B3) or its precursor tryptophan.  Risk factors include poverty, a diet poor not fortified with niacin (such as maize), alcoholism, carcinoid syndrome and drugs such as isoniazid and azathioprine.1,2The rash is typically a symmetrical photo-distributed rash with a thick scale likened to shellac.

Cheilitis and glossitis are commonly associated with pellagra, as well as other vitamin deficiencies. Dementia and diarrhea are other commonly associated symptoms, completing the “4 Ds” of Pellagra (Dementia, Diarrhea, Dermatitis and Death).2 The World Health Organization recommends treatment of pellagra with Nicotinamide 300 mg by mouth divided 2-3 times daily for 3-4 weeks.4 Repletion with a daily multivitamin can be done to treat for other suspected concomitant vitamin deficiencies.

Answer D is correct to confirm a diagnosis of Pellagra. Acrodermatitis enteropathica due to Zinc deficiency commonly involves the peri-oral, acral and intertriginous areas. (Answer A). Vitamin C deficiency can present as perifollicular purpura, gingival bleeding and corkscrew hair (Answer B). Answer C is to evaluate for Sezary syndrome, which can present with leonine facies, however the plaques and tumoral lesions are typically in photo protected areas. Finally a mineral prep would evaluate for scabies, which less likely involves the face and scalp (Answer E). The rest of the answers are reasonable next steps to narrow down the differential diagnosis; however the photo distribution is a typical finding in pellagra.


  1. Bolognia, Jean L. Dermatology volume 2. Mosby, 2018.
  2. Hegyi J, Schwartz RA, Hegyi V. Pellagra: dermatitis, dementia, and diarrhea. Int J Dermatol. 2004 Jan;43(1):1-5. doi: 10.1111/j.1365-4632.2004.01959.x. PMID: 14693013.
  3. World Health Organization. Pellagra and its prevention and control in major emergencies. 2000

Author Krista Reznik

More posts by Krista Reznik