Sir, Pellagra, once known as Austrian leprosy, is a nutritional disorder that occurs as a result of niacin deficiency.[1] It is classically known as the disease of 4 D's-dermatitis, dementia, diarrhea and death.[2] Dermatitis associated with pellagra is usually seen over photoexposed sites with associated photosensitivity.[3] We herein describe a case of pellagra that was unusual in having lesions both over exposed as well as unexposed sites. A 68-year-old female came to us with complaints of itchy, well-demarcated, hyperpigmented, scaly lesions over the body since seven months. The lesions began over the dorsum of hands, arms, face and neck as erythematous, itchy plaques with severe photosensitivity which, with time, spread to the non-photoexposed sites, namely, the trunk, perineum, buttocks and thighs. With the passage of time, the lesions became hyperpigmented with well-demarcated borders and large brown to black, loosely adherent scales [Figure 1a–c]. The patient was lethargic and apathetic, with auditory hallucinations and loss of appetite. She also complained of soreness of the mouth. There was presence of maceration in the axilla, inframammary area, groins and perineum. Keeping in mind the clinical picture, a provisional diagnosis of pellagra and acquired zinc deficiency was considered. The patient was investigated. Her hemoglobin was 11 g/dl. Her serum zinc level was normal at 78.79 ug/dl, (normal 70-120 ug/dl), serum alkaline phosphatase level (a marker of functional zinc deficiency) was also normal 89 mg/dl, (normal 39-104 mg/dl). Her blood counts, hematological indices, liver and renal functional tests and urinalysis were within normal limits. Serology for human immunodeficiency virus, hepatitis B virus hepatitis C viruses was non-reactive and antinuclear antibody profile was also negative. Histopathology showed hyperkeratosis, acanthosis, vacuolization of stratum malpighii cells and vacuolar degeneration of the basal cell layer. The dermis showed a chronic inflammatory infiltrate. [Figure 2a and b]. Patient was placed on niacin supplementation with a test dose of 375 mg twice a day, along with vitamin B complex supplementation. The patient was also advised topical application of sunscreen and emollients. Within two days of starting treatment, the patient showed marked improvement. The borders of the lesions became less well-defined, there was decrease in erythema and there was remarkable improvement in the mental status of the patient. The patient was continued on high dose niacin (375 mg BD) for 4 weeks along with daily vitamin B complex supplementation. The patient was continued on vitamin B complex supplementation alone for another 8 weeks. At 6 months follow-up, the patient was asymptomatic with no signs of relapse; however, mild post inflammatory hyperpigmentation persisted [Figure 3a–c].Figure 1: Patient at the time of presentation with well defined red-brown scaly plaques on face, chest, upper arms along with the typical Casal's neck appearance (a), brown scaly plaques with a well-defined hyperpigmented border involving the perineum, medial aspect of the thighs upto the knees (b), and on the back, buttocks, and posterior aspect of thighs (c)Figure 2: (a) Histopathology of a skin lesion showing hyperkeratosis and acanthosis of the epidermis (H and E, ×40). (b) Histopathology at a higher magnification showing vacuolization of stratum malpighii cells and basal layer cells (H and E ×400)Figure 3: The same patient after 6 months of follow-up with clearance of lesions over the sun exposed areas (a). Lesions on the thighs and perineum (b), and the back, buttocks and posterior aspect of thighs healed with residual hyperpigmentationClinical manifestations of pellagra are an important clue to its diagnosis. Pellagra, once a common disease is becoming increasingly rare, though still endemic among the maize eating populations of India.[4] This case is one of the few cases of pellagra with typical sunburn-like red brown, symmetrical, scaly plaques over the exposed as well as non-exposed areas. Photosensitive lesions over the exposed sites could possibly be explained by the accumulation of kynurenic acid in cells due to niacin deficiency,[3] and lesions over non-exposed sites could be due to multiple nutritional deficiencies such as protein deficiency, and vitamin A and zinc deficiency.[5] Low urinary levels of N-methylnicotinamide and pyridone of less than 1.5 mg in 24 h indicate severe Niacin deficiency and can be used whenever in doubt.[1] Treatment of pellagra includes exogenous Niacin, multivitamin and zinc supplementation and a diet rich in calories along with topical emollients and sunscreen for skin lesions.[1] The prevention of pellagra is based on nutritional advice that includes avoidance foods such as jowar, ragi, maize and alcohol and inclusion of diet rich in niacin such as eggs, bran, meat, poultry, fish, legumes and seeds.[14]
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Aug 7, 2023
Abdulla Abu-Bakr Badawy 
Open Access