Keratosis pilaris (KP; also follicular keratosis, lichen pilaris, or colloquially chicken skin) is a common, autosomal-dominant, genetic condition of the skins hair follicles characterized by the appearance of possibly itchy, small, gooseflesh-like bumps, with varying degrees of reddening or inflammation. It most often appears on the outer sides of the upper arms (the forearms can also be affected), thighs, face, back, and buttocks; KP can also occur on the hands, and tops of legs, sides, or any body part except glabrous (hairless) skin (like the palms or soles of feet). Often the lesions can appear on the face, which may be mistaken for acne or folliculitis. The several types of KP have been associated with pregnancy, type 1 diabetes mellitus, obesity, dry skin, allergic diseases (e.g., atopic dermatitis), and rarely cancer. Many rarer types of the disorder are part of inherited genetic syndromes.The cause of KP is not completely understood. As of 2018, KP is thought to be due to abnormalities in the process of depositing the protein keratin in hair follicles, abnormalities in the hair shaft, or both. KP is usually diagnosed by a medical professional based on the appearance of the skin, but dermoscopy can be used, as well, if the diagnosis is unclear. Variants of the ABCA12 gene have been associated with KP.KP is the most common disorder of the hair follicle in children. How common KP is in adults is unclear, with estimates ranging from 0.75 to 34% of the population.
KP does not bear any known, long-term health implications, nor is it associated with increased mortality or morbidity. It is not related to goose bumps, which result from muscle contractions, except that both occur in the area where the hair shaft exits the skin. Gallery
Treatment
KP is medically harmless, but many individuals may seek treatment, as the condition can cause emotional distress. Topical creams and lotions are currently the most commonly used treatment for KP, specifically those consisting of moisturizing or keratolytic treatments, including urea, lactic acid, glycolic acid, salicylic acid, vitamin D, fish oil, or topical retinoids such as tretinoin. Improvement of the skin often takes months, and the bumps are likely to return. Limiting time in the shower and using gentle exfoliation to unplug pores can help. Many products are available that apply abrasive materials, with alpha or beta hydroxy acids to assist with exfoliation. Some cases of KP have been successfully treated with laser therapy, which involves passing intense bursts of light into targeted areas of the skin. Depending on the bodys response to the treatment, multiple sessions over the course of a few months may be necessary. Epidemiology
Worldwide, KP affects an estimated 30 to 50% of the adult population, and around 50 to 80% of all adolescents. It is more common in women than in men, and it is often present in otherwise healthy individuals. The skin condition is prevalent in persons of all ethnicities, and no particular ethnicity is at higher risk for developing KP.