Hypovitaminosis A
Hypovitaminosis A (also known as Follicular Hyperkeratosis and "Phrynoderma" which means Toad Skin) is common in children in the developing world, most often associated with diseases of fat malabsorption.[1]:479
It is seen as rough, hyperkeratotic, follicular papules on the skin of elbows and knees.[2]
Terminology
The term "phrynoderma" was coined by Nicholls in 1933 to describe the "toad-like" appearance of the skin of undernourished labourers.
Signs and Symptoms
Adjunctive symptoms, such as cheilitis, glossitis, blepharitis, night blindness, diarrhea, muscle weakness and neuritis, may develop when hypovitaminosis A is predominant relative to other vitamin deficiencies. The lesions could be discrete, keratotic, follicular, pigmented or skin colored, acuminate papules in all patients.Epidermal hyperkeratosis, follicular hyperkeratosis, and follicular plugging will be present in almost all the patients or very few of the above specified in some of the patients.
Causes
Deficiencies of vitamins A and E, B complex vitamins, and essential fatty acids have all been implicated in the etiology of follicular hyperkeratosis. Phrynoderma is a form of follicular hyperkeratosis that is associated with nutritional deficiencies. It is endemic to poor populations but is rare in developed countries. In developed countries, phrynoderma most often occurs as a result of malabsorption due to surgical or medical causes, such as small-bowel bypass surgery, colectomy and pancreatic insufficiency. However, phrynoderma can also develop if a patient follows a calorie-restricted diet (< 700 kcal/d) and strictly avoids vegetables, fruit and fats. However some studies have showed that phrynoderma could be hereditary.[3]
Treatment
Health care providers should be attentive to the nutritional needs of patients at risk for malnutrition, including those who have been prescribed a strict weight-loss regimen and those who may be in a malabsorptive state, such as patients who have undergone bariatric surgery. For these patients, health care providers should recommend diets, or at least supplements, that are rich in vitamins A, B, C and E, including foods such as yellow vegetables, green leafy vegetables, carrots, whole-milk derivatives, eggs, fish and oils (e.g., fish-liver oil, soybean oil, safflower oil, sunflower oil, corn oil, palm oil, cottonseed oil), as well as unprocessed cereal grains and nuts. However they must consult a dermatologist.