What abnormalities occur with vitamin A deficiency?

This disorder primarily involves the skin and eyes. Phrynoderma, the name applied to the cutaneous eruption of vitamin A deficiency, is a keratotic follicular eruption that initially appears on the proximal extremities. It eventually extends to the trunk, back, abdomen, buttocks, and neck. Although phrynoderma is widely accepted as being specific for vitamin A deficiency, it has recently been suggested that it may be a manifestation of severe malnutrition associated with deficiencies of multiple critical vitamins and essential fatty acids. Facial lesions may resemble large comedones of acne. Eye symptoms include nyctalopia (delayed dark adaptation, the earliest finding), night blindness, and xerophthalmia. Objective findings are Bitot’s spots, which are areas of shed corneal epithelium, and in severe disease, keratomalacia. Vitamin A deficiency is most commonly caused by malabsorption disorders.

Maronn M, Allen DM, Esterly NB: Phrynoderma: a manifestation of vitamin A deficiency?...The rest of the story, Pediatr Dermatol 22:60–63, 2005.

Sommer A: Vitamin A deficiency and clinical disease: an historical overview, J Nutr 138:1835–1839, 2008.