Hyperkeratosis
thickening of the stratum corneum (the outermost layer of the epidermis), often associated with the presence of an abnormal quantity of keratin
Hyperkeratosis is thickening of the stratum corneum (the outermost layer of the epidermis, or skin), often associated with the presence of an abnormal quantity of keratin, and is usually accompanied by an increase in the granular layer. As the corneum layer normally varies greatly in thickness in different sites, some experience is needed to assess minor degrees of hyperkeratosis.
It can be caused by vitamin A deficiency or chronic exposure to arsenic.
Hyperkeratosis can also be caused by B-Raf inhibitor drugs such as vemurafenib and dabrafenib.
It can be treated with urea-containing creams, which dissolve the intercellular matrix of the cells of the stratum corneum, promoting desquamation of scaly skin, eventually resulting in softening of hyperkeratotic areas.
Types
Follicular
Follicular hyperkeratosis, also known as keratosis pilaris (KP), is a skin condition characterized by excessive development of keratin in hair follicles, resulting in rough, cone-shaped, elevated papules. The openings are often closed with a white plug of encrusted sebum. When called phrynoderma, the condition is associated with nutritional deficiency or malnourishment.
This condition has been shown in several small-scale studies to respond well to supplementation with vitamins and fats rich in essential fatty acids. Deficiencies of vitamin E, vitamin A, and B-complex vitamins have been implicated in causing the condition.
This brief starts where responsible research should: with the source description of “Hyperkeratosis” as thickening of the stratum corneum (the outermost layer of the epidermis), often associated with the presence of an abnormal quantity of keratin. Everything that follows is an evidence route, not borrowed authority.
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The subject matters to the general reference register because the source frames it as thickening of the stratum corneum (the outermost layer of the epidermis), often associated with the presence of an abnormal quantity of keratin. Its deeper value depends on whether names, dates, institutions and citations support that framing.
The citation trail is more important than the brevity of the summary: it shows where individual claims can be examined in context. The source revision retrieved here is dated Jul 3, 2026. The linked authority identifier is Q1640998. None of the 0 selected statements returned an explicit reference.
A concise general-reference account can conceal disagreements about scope, terminology or the weight assigned to individual sources. The lead is largely declarative, so disagreement and counter-evidence require a deliberate search beyond the opening account. Authority statements aid reconciliation but still require their own references, qualifiers and ranks to be checked.
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This entry incorporates text from “Hyperkeratosis” on English Wikipedia. Contributors are listed in the page history. Text is available under the Creative Commons Attribution-ShareAlike 4.0 License. Selected authority identifiers and statements are retrieved from Wikidata under CC0; their references and qualifiers remain part of the verification path.