Cutaneous Manifestations of Vitamin a Deficiency in Children

Vitamin A and Keratinization

“…For instance, in the skin the clinical features of dryness, scaling, and follicular papules (phrynoderma) reflect a histologie state that is char¬ acterized by generalized hyperkeratosis with prominent follicular kera¬ tin plugs.27 More dramatic changes occur in the sweat glands which, in advanced disease, undergo atrophy and keratinizing squamous metapla¬ sia. 27,28 Comparable changes occur in the mucous membranes of the nares, trachea, bronchi, salivary glands, and genitourinary tract, all of which may become anatomically and func¬ tionally distorted by the production of keratin.21' In the intestinal mucosa, there is atrophy and goblet-cell degeneration but no keratin forma¬ tion.2" This implies that the different epithelia have different thresholds of responsiveness, as suggested by Fell and Mellanby.3" Thus, the skin may be regarded as having a high thresh¬ old which, even at normal plasma levels of vitamin A, is able to resist the antikeratinizing influence. The gastrointestinal tract, however, seems to have a low threshold, allow¬ ing expression of the antikeratinizing effect even at very low plasma levels.…”

Skin Changes of Nutritional Origin

“…Their observations have been amply confirmed, and many descriptions of similar lesions seen in this country are now on record. [48][49][50][51][52][53] The early change is one of simple dryness (xeroderma).48,53 When more severe, according to Markowitz,54 the normal skin epithelium atrophies and is replaced by proliferating basal cells that become keratinized. A similar process in the skin glands and ducts causes accumulation of keratinized epithelium, which by protruding from the pilosebaceous follicular orifices results in the hyperkeratotic papules (hyperkeratosis follicularis) so characteristic of this disorder.…”