Pellagra
Pellagra is a systemic disease that occurs due to vitamin B3 deficiency. Primary pellagra is due to inadequate intake of vitamin B3 whereas secondary pellagra is be due to other causes despite adequate intake such as malabsorption or it can be drug induced. The disease is characterised by the 4D's - dermatitis, diarrhoea, dementia and death. The skin changes usually occur first and include photosensitivity of the exposed skin sites that initially resembles sunburn and eventually becomes thickened, hyperpigmented and dry. Sometimes a hyperpigmented band/collar becomes visible around the neck and is known as the Casal's necklace. The pellagra glove and boot is another sign in which there are hyperpigmented plaques and fissuring of the hands and feet. There are anogenital and mucosal lesions too (glossitis, cheilitis, inflammed vaginal mucosa). Other symptoms include loss of appetite, vomiting, abdominal pain and diarrhea. Not all the signs and symptoms appear in every individual. The neuropsychiatric symptoms usually occur late in the disease and include apathy, headache, anxiety and even dementia. The treatment consists of general measures and specific measures. For secondary pellagra, treating the underlying cause helps to treat the disease. Topical emollients have proven to be beneficial for the skin changes. Moreover, 300 mg nicotinamide in an oral divided daily dose for 3–4 weeks is recommended to treat pellagra.