Hyperkeratinization (

American English American English, sometimes called United States English or U.S. English, is the set of variety (linguistics), varieties of the English language native to the United States. English is the Languages of the United States, most widely spoken lan ...

or hyperkeratinisation in

British British may refer to: Peoples, culture, and language * British people, nationals or natives of the United Kingdom, British Overseas Territories, and Crown Dependencies. ** Britishness, the British identity and common culture * British English, ...

) is a

disorder Disorder may refer to randomness, non-order, or no intelligible pattern. Disorder may also refer to: Healthcare * Disorder (medicine), a functional abnormality or disturbance * Mental disorder or psychological disorder, a psychological pattern a ...

of the cells lining the inside of a

hair follicle The hair follicle is an organ found in mammalian skin. It resides in the dermal layer of the skin and is made up of 20 different cell types, each with distinct functions. The hair follicle regulates hair growth via a complex interaction between h ...

. It is the normal function of these cells to detach or slough off (

desquamate Desquamation occurs when the outermost layer of a tissue, such as the skin, is shed. The term is . Physiologic desquamation Keratinocyte Keratinocytes are the primary type of cell found in the epidermis, the outermost layer of the skin. In ...

) from the skin lining at normal intervals. The dead cells are then forced out of the follicle (primarily by the growing hair). However, in hyperkeratinization, this process is interrupted and a number of these dead skin cells do not leave the follicle because of an excess of

keratin Keratin () is one of a family of structural fibrous proteins also known as ''scleroproteins''. Alpha-keratin (α-keratin) is a type of keratin found in vertebrates. It is the key structural material making up scales, hair, nails, feathers, ho ...

, a natural protein found in the skin. This excess of keratin, which is influenced by genetics, results in an increased adherence/bonding of dead skin cells together. This cohesion of cells will block or "cap" the hair follicle (leading to

keratosis pilaris Keratosis pilaris (KP; also follicular keratosis, lichen pilaris, or colloquially chicken skin) is a common, autosomal- dominant, genetic condition of the skin's hair follicles characterized by the appearance of possibly itchy, small, goosefle ...

) or clog the

sebaceous A sebaceous gland is a microscopic exocrine gland in the skin that opens into a hair follicle to secrete an oily or waxy matter, called sebum, which lubricates the hair and skin of mammals. In humans, sebaceous glands occur in the greatest number ...

/oil duct (leading to

acne Acne, also known as ''acne vulgaris'', is a long-term Cutaneous condition, skin condition that occurs when Keratinocyte, dead skin cells and Sebum, oil from the skin clog hair follicles. Typical features of the condition include comedo, black ...

). Pathogens may also play a role in causing, perpetuating, or simply taking advantage of this phenomenon, such as virulent sub-strains of ''

Cutibacterium acnes ''Cutibacterium acnes'' (formerly ''Propionibacterium acnes'') is the relatively slow-growing, typically aerotolerant Anaerobic organism, anaerobic, gram-positive bacterium (rod) linked to the skin condition of acne vulgaris, acne; it can also ca ...

'' and irregular migration of ''

Staphylococcus epidermidis ''Staphylococcus epidermidis'' is a Gram-positive bacterium, and one of over 40 species belonging to the genus '' Staphylococcus''. It is part of the normal human microbiota, typically the skin microbiota, and less commonly the mucosal microbio ...

'' from the outer surface of the skin into the follicle, where

commensal Commensalism is a long-term biological interaction (symbiosis) in which members of one species gain benefits while those of the other species neither benefit nor are harmed. This is in contrast with mutualism, in which both organisms benefit fro ...

strains of ''C. acnes'' exclusively habitate. It itches mildly at times, and strongly at others. Very often it cannot be felt at all.

References

Dermatologic terminology {{Dermatology-stub

See also

References