Casal necklace is seen in-

Ans. is 'c' i.e., Pellagra Pellagra* Pellagra, the classic niacin deficiency disease, occurs chiefly in populations where corn (maize), a poor source of tryptophan, is the major foodstuff". A severe dietary imbalance, such as in anorexia nervosa and in war or famine conditions, also can cause pellagra.* Pellagra can also develop in conditions associated with disturbed tryptophan metabolism such as carcinoid syndrome and Hartnup disease.* The early symptoms of pellagra are vague: anorexia, lassitude, weakness, burning sensation, numbness, and dizziness.* After a long period of deficiency, the classic triad of dermatitis, diarrhea, and dementia appears.* Dermatitis, the most characteristic manifestation of pellagra, can develop suddenly or insidiously and may be initiated by irritants, including intense sunlight. The lesions first appear as symmetric areas of erythema on exposed surfaces, resembling sunburn, and might go unrecognized. The lesions are usually sharply demarcated from the surrounding healthy skin, and their distribution can change frequently. The lesions on the hands and feet often have the appearance of a glove or stocking. Similar demarcations can also occur around the neck (Casal necklace).* In some cases, vesicles and bullae develop (wet type). In others, there may be suppuration beneath the scaly, crusted epidermis; in still others, the swelling can disappear after a short time, followed by desquamation.