Bitot's spots and vitamin A deficiency in a child from the UK

A loss of goblet cells in xerophthalmia alters the protective mucous layer resulting in an overlying accumulation of Gram positive bacilli and keratin debris on the paralimbal conjunctiva. 3 A rapid response to vitamin A replacement is usual with goblet cells reappearing within 2 weeks 3 and resolution within 3 months. 4 The World Health Organization (WHO) categorised the ocular manifestations of vitamin A deficiency as XN night blindness, X1A conjunctival xerosis, X1B Bitot's spot, X2 corneal xerosis, X3A corneal ulceration or keratomalacia involving one third or less of the cornea, XS corneal scar, and XF xerophthalmia fundus. 5 While this describes the usual pattern of progression of the disease, a study of 114 cases of Bitot's spots found over 80% had no concurrent clinical night blindness as in this patient. 3 Formal night blindness testing was not undertaken in this case as clinical history of poor night vision is believed to be a sensitive test in vitamin A deficiency. 6 The condition improved after dietary change although the definitive treatment is one or two doses of vitamin A (200 000 IU).