Follicular Keratosis - Phrynoderma

Overview
Follicular hyperkeratosis  a skin condition characterized by excessive development of keratin in hair follicles, resulting in rough, cone-shaped, elevated papules whose openings are often closed with a white plug of sebum.

Deficiencies of vitamins A and E, B complex vitamins, and essential fatty acids have all been implicated in the etiology of follicular hyperkeratosis. Called also phrynoderma.

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.

The term "phrynoderma" was coined by Nicholls in 1933 to describe the "toad-like" appearance of the skin of undernourished labourers. This form of dermatosis can be caused by isolated deficiencies of vitamins A, B complex, C and E.

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.

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.

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.

Many mild cases of phrynoderma may be overlooked, but if detected early, the underlying nutritional imbalances may be corrected.