Hyperkeratinization is a disorder

Disease

A disease is an abnormal condition affecting the body of an organism. It is often construed to be a medical condition associated with specific symptoms and signs. It may be caused by external factors, such as infectious disease, or it may be caused by internal dysfunctions, such as autoimmune...

 of the cells lining the inside of a hair follicle

Hair follicle

A hair follicle is a skin organ that produces hair. Hair production occurs in phases, including a growth phase , and cessation phase , and a rest phase . Stem cells are principally responsible for the production of hair....

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

Keratin refers to a family of fibrous structural proteins. Keratin is the key of structural material making up the outer layer of human skin. It is also the key structural component of hair and nails...

, 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

Keratosis pilaris is a common, autosomal dominant, genetic follicular condition that is manifested by the appearance of rough bumps on the skin...

) or clog the sebaceous/oil duct (leading to acne

Acne vulgaris

Acne vulgaris is a common human skin disease, characterized by areas of skin with seborrhea , comedones , papules , pustules , Nodules and possibly scarring...

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

Propionibacterium acnes

Propionibacterium acnes is a relatively slow growing, typically aerotolerant anaerobic gram positive bacterium that is linked to the skin condition acne; it can also cause chronic blepharitis and endophthalmitis, the latter particularly following intraocular surgery...

and irregular migration of Staphylococcus epidermidis

Staphylococcus epidermidis

Staphylococcus epidermidis is one of thirty-three known species belonging to the genus Staphylococcus. It is part of human skin flora, and consequently part of human flora. It can also be found in the mucous membranes and in animals. Due to contamination, it is probably the most common species...

from the outer surface of the skin into the follicle, where commensal strains of P. acnes exclusively habitate.