Bitot's spots and vitamin A deficiency in a child from the UK
- Mr Carlos Pavesio
- Accepted 11 September 2000
Editor,—Prolonged nutritional deficiency of vitamin A results in xerophthalmia. Bitot's spots are an early manifestation of this condition.1 While xerophthalmia is responsible for 70% of childhood blindness in developing countries it is rare in the Western world.2 We report a case of a British, vegetarian girl who developed Bitot's spots.
A 7 year old, indigenous, British, white girl presented with triangular white, foamy lesions in the temporal paralimbal areas of both eyes (Fig1). She had no visual complaints and denied night blindness or any systemic problem. She had been a vegetarian for 2 years, and preferred processed, frozen food to fresh fruit or vegetables. On examination her unaided Snellen visual acuity was 6/6 and her tear film healthy with a normal tear break up time and no mucous filaments. Funduscopy was normal. Vitamin A levels were depressed at 0.35 μmol/l (normal range 0.4–1.1 μmol/l). Electroretinography was normal.
The patient was referred to a paediatric dietician who enabled her to find a more nutritious diet that she found acceptable. The Bitot's spots had visibly lessened by 6 weeks and disappeared by 3 months.
This case illustrates that the manifestations of vitamin A deficiency can occur in children in the Western world because of poor dietary education. In the UK xerophthalmia is more usually associated with alcoholism/hepatic cirrhosis, or refugee status.
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 weeks3 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.5While 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). Those that do not respond are frequently over the age of about 6 years and may have normal vitamin A levels and possible previous deficiency.7
Bitot's spots are an important clinical sign that should prompt a careful dietary history which may enable patients to avert the devastating consequences of xerophthalmia.8