A 45 y.o. transexual female with HIV and CD4 count of <5 presents with a rash

What is the differential diagnosis?

Our patient had photodermatitis.  This is a form of  allergic contact dermatitis is which the allergen is activated by sunlight.

Causes of photodermatitis

Medications

                Sulfa, psoralens, tetracyclines, benzoylperoxide, retinoids, amiodarone, ibuprofen , naprosyn

                Lemon oil, PABA (found in sunscreens). Hexachlorophene( found in antibacterial soaps)

Plant related photodermatitis

Citrus fruits including limes and grapefruit of the Rutaceae family , psoralens found in celery, carrot or parsley( the family Apiaceae)

Vitamin deficiency

Pellagra- lack of B3 either by lack of the vitamin in the diet or  inability to use the niacin consumed.

pellegra in an alcoholic

Pellegra is common in people who eat a corn based diet when the corn is not processed with alkali which makes niacin available for absorption.The name comes from Pelle agra, Italian for rough skin.  It was first described in 1735 in Spain by Gaspar Casal.  Pellegra  was widespread in the American south in the 1900s with more than 3 million people affected. Dr. Joseph Goldberger traced the disease to corn by feeding prisoners cereal diets until they developed the classic skin lesions.  Now corn is processed with alkali to make the niacin bioavailable.

Pellegra is often seen in alcoholics,  end stage HIV, malabsorption and carcinoid syndrome (due to excess turnover of tryptophan, precursor of niacin, to serotonin)

Our patient was treated with nicotinomide and all her herbal supplements were stopped.  She had also been on high doses of grapefruit powder and shitake mushroom powder.  Her rash resolved after a week in the hospital. Below is a chart of the timeline of vitamin deficiencies.

Rodriguez E. Valbuena M, Rey M Porras de Quintana L. 2006 Causal agents of photoalleric contact dermatitis diagnosed in the national institute of dermatology of Colombia. Photodermatol Photoimmunol Photomed 22(4) 189-192.

Ngan V. 2003 Pellegra DermNet New Zealand, April 9 2017.

Hegyi J, Schwartz, R, Hegyi V. Pellegra: Dermatitis, dementia, and diarrhea. International Journal of Dermatology 43(1) 1-5. doi 10.111/j 1365-4632. 2004.01959 PMID 14693013.

Savvvoula S, Pellegra: A non-eradicated old disease, Clin Pract 2014 March 27, 4(1). 637