08/03/2026
Vitamin A Deficiency (VAD)
Definition:
Vitamin A deficiency is a condition resulting from insufficient intake or absorption of vitamin A, leading to ocular, epithelial, and immune system abnormalities.
Causes
• Dietary deficiency (common in developing countries)
• Fat malabsorption (pancreatic insufficiency, celiac disease, cholestasis)
• Liver disease (affects storage)
• Increased requirements (pregnancy, infection)
Functions of Vitamin A
• Vision: component of rhodopsin for night vision
• Epithelial integrity: skin, mucous membranes
• Immune function: enhances resistance to infections
• Growth & development: cell differentiation
• Reproduction: essential for spermatogenesis and fetal development
Clinical Features
1. Ocular Signs
• Night blindness (nyctalopia) – earliest symptom
• Conjunctival xerosis – dryness of conjunctiva
• Bitot spots – triangular foamy white spots on conjunctiva
• Corneal xerosis / keratomalacia – can lead to corneal ulceration and blindness
2. Skin & Epithelial Changes
• Dry, rough skin (hyperkeratosis)
• Follicular hyperkeratosis (“toad skin”)
• Susceptibility to infections (respiratory, gastrointestinal)
3. Growth and Development
• Stunted growth in children
• Impaired immune response → recurrent infections
Laboratory Findings
• Serum retinol < 0.7 µmol/L
• Low liver stores of vitamin A (in severe cases)
Management
• Supplementation: high-dose vitamin A capsules (per WHO guidelines)
• Dietary improvement: liver, egg yolk, dairy, green leafy vegetables, yellow/orange fruits
• Treat underlying malabsorption or infections
Prevention
• Public health measures in children: routine vitamin A supplementation
• Nutritional education
• Fortification of staple foods
• Night blindness is the earliest ocular sign of vitamin A deficiency.
• Bitot spots are pathognomonic.
• Severe deficiency can lead to keratomalacia and irreversible blindness.
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