Keratosis pilaris: Description, Causes and Risk Factors:
Keratosis pilaris is a genetic disorder of keratinization of hair follicles of the skin. It is an extremely common benign condition that manifests as small, rough folliculocentric keratotic papules, often described as chicken bumps, chicken skin, or goose bumps, in characteristic areas of the body, particularly the outer-upper arms and thighs. Although no clear etiology has been defined, keratosis pilaris is often described in association with other dry skin conditions such as ichthyosis vulgaris, xerosis, and, less commonly, with atopic dermatitis, including conditions of asthma and allergies.
Keratosis pilaris affects nearly 50-80% of all adolescents and approximately 40% of adults. It is frequently noted in otherwise asymptomatic patients visiting dermatologists for other conditions. Most people with keratosis pilaris are unaware the condition has a designated medical term or that it is treatable. In general, keratosis pilaris is frequently cosmetically displeasing but medically harmless.
Overall, keratosis pilaris is described as a condition of childhood and adolescence. Although it often becomes more exaggerated at puberty, it frequently improves with age. However, many adults have keratosis pilaris late into senescence. Approximately 30-50% of patients have a positive family history. Autosomal dominant inheritance with variable penetrance has been described.
Seasonal variation is sometimes described, with improvement of symptoms in summer months. Dry skin in winter tends to worsen symptoms for some groups of patients. Overall, keratosis pilaris is self-limited and, again, tends to improve with age in many patients. Some patients have lifelong keratosis pilaris with periods of remissions and exacerbations. More widespread atypical cases may be cosmetically disfiguring and psychologically distressing.
Keratosis pilaris is a genetically based disorder of hyperkeratinization of the skin. An excess formation and/or buildup of keratin is thought to cause the abrasive goose-bump texture of the skin. In these patients, the process of keratinization (the formation of epidermal skin) is faulty. One theory is that surplus skin cells build up around individual hair follicles. The individual follicular bumps are often caused by a hair that is unable to reach the surface and becomes trapped beneath the keratin debris. Often, patients develop mild erythema around the hair follicles, which is indicative of the inflammatory condition. Often, a small, coiled hair can be seen beneath the papule. Not all the bumps have associated hairs underneath. Papules are thought to arise from excessive accumulation of keratin at the follicular orifice.
Keratosis pilaris is not associated with increased mortality or morbidity. Often, patients are bothered by the cosmetic appearance of their skin and its rough, gooseflesh texture. Obesity has been implicated in a wide spectrum of dermatologic diseases, including keratosis pilaris. Keratosis pilaris is commonly present in otherwise healthy individuals and does not have any known, long-term health implications.
Physical findings of keratosis pilaris are limited to the skin. Upon gross examination, the skin of the outer-upper arms and thighs is frequently affected. The skin is described as chicken skin or goose bumps. Often, 10-100 very small, slightly rough bumps
are scattered in an area. Palpation may reveal a fine, sandpaper-like texture to the area. Some of the bumps may be slightly red or have an accompanying light-red halo, indicating inflammation. In some instances, scratching away the surface of some bumps may reveal a small
No specific laboratory tests aid in the diagnosis of keratosis pilaris. The diagnosis of keratosis pilaris is very straightforward and is based on a typical skin appearance in areas such as the upper arms. A family history of keratosis pilaris is also very helpful because keratosis pilaris has a strong genetic component. The diagnosis is confirmed on the basis of the physician's clinical examination findings. A few other medical conditions look similar to keratosis pilaris, and these must be excluded.
Skin biopsy with histopathological examination may be useful in atypical cases.
Histopathology of keratosis pilaris lesions shows the triad of epidermal hyperkeratosis, hypergranulosis, and plugging of individual hair follicles. The upper dermis may have mild superficial perivascular lymphocytic inflammatory changes.
Many treatment options and skin care recipes are available for treating keratosis pilaris. Many patients have very good temporary improvement following a regular skin care program. As a general rule, treatment needs to be continuous. Because no single therapy is effective, the list of potential lotions and creams is long. Importantly, keep in mind that as with any condition, no therapy is uniformly effective in all people. Complete clearing may not be possible.
General measures to prevent excessive skin dryness, such as using mild soap-less cleansers (eg, Dove, Cetaphil), are recommended, and lubrication is the mainstay of treatment for nearly all cases.
Best results may be achieved with combination therapy.
Mild cases of keratosis pilaris may be improved with basic lubrication using over-the-counter moisturizer lotions such as Cetaphil, Purpose, or Lubriderm.
- Additional available therapeutic options for more involved cases of keratosis pilaris include lactic acid lotions (AmLactin, Lac-Hydrin), alpha hydroxy acid lotions (Glytone, glycolic body lotions, urea cream (Carmol 10, Carmol 20, Carmol 40, Urix 40), salicylic acid (Salex lotion), and topical steroid creams (triamcinolone 0.1%, Locoid Lipocream), retinoic acid products such as tretinoin (Retin-A), tazarotene (Tazorac), and adapalene (Differin). Specially mixed “designer” compound creams with multiple different combined ingredients can also be prescribed by physicians.
- The affected area may be washed once or twice a day with a gentle cleanser such as Dove. Acne-prone skin may benefit from more therapeutic cleansers such as Gly-Sal, Proactiv, salicylic acid, or benzoyl peroxide.
- Lotions should be gently massaged into the affected area 2-3 times a day. Irritated or abraded skin should be treated only with bland moisturizers until the inflammation resolves.
- Occasionally, physicians may prescribe a 7- to 10-day course of a medium potency, emollient-based topical steroid cream (eg, Locoid Lipocream, Cloderm) to be applied once or twice a day for inflamed, red rash areas. Once the inflammation has remitted, the residual dry rough bumps may be treated with a routine of twice-daily application of a compounded preparation of 2-3% salicylic acid in 20% urea cream.
- Intermittent dosing of topical retinoids (eg, weekly or biweekly) seems to be quite effective and well tolerated, but usually the response is only partial. After initial clearing with stronger medications, patients may then be placed on a milder maintenance regimen.
- Persistent skin discoloration, termed hyperpigmentation, may be treated with fading creams such as hydroquinone 4%, kojic acid, and azelaic acid 15-20%. Special compounded creams for particularly resistant skin discoloration using higher concentrations of hydroquinone 6%, 8%, and 10% may also be formulated by compounding pharmacists. Higher concentrations of hydroquinone may be irritating and carry an increased risk of adverse effects, including ochronosis.
- Keratosis pilaris may be treated with topical immunomodulators such as pimecrolimus (Elidel) or tacrolimus (Protopic). Although these products are approved for atopic dermatitis and eczema, their use would be considered off label for keratosis pilaris. These may be used in more resistant cases or when the patient has considerable skin redness or inflammation.
Other Treatment Options:
Photodynamic therapy (PDT) using a 2-step combination of a topical photosensitizer and a light source may be used in off-label fashion for the temporary treatment of keratosis pilaris. Available photosensitizers include aminolevulinic acid (Levulan) or methyl levulinate (Metvixia). Light sources include sunlight, blue light (417 nm), red light (630 nm), and multiple laser devices. PDT has been anecdotally reported as effective, but this successful use of off-label photodynamic therapy requires confirmation.
- Laser hair removal (LHR) has been used in keratosis pilaris to decrease hair growth in affected areas. Theoretically, LHR may help decrease the portion of bumps in keratosis pilaris caused by small, coiled, ingrown hairs. There are no studies showing a cure of keratosis pilaris with LHR.
- Laser therapies including more aggressive resurfacing lasers, carbon dioxide, fractional lasers, and other aggressive laser therapies have been used in limited cases for keratosis pilaris. There are no studies showing a cure of keratosis pilaris with these types of lasers.
Severe cases of keratosis pilaris have been treated orally with isotretinoin pills for several months. Isotretinoin is generally a very potent oral medication reserved for severe, resistant, or scarring cases of acne. Its use in keratosis pilaris would be considered off label and not routine. There are no studies showing a permanent cure of keratosis pilaris using isotretinoin.
Vitamin D (calcipotriol) is not effective for keratosis pilaris, but clinical trials have found it moderately effective for ichthyosis. As with most treatments for keratosis pilaris, data exist only in the form of small group observations and anecdotal reports. Because keratosis pilaris is generally a chronic condition that requires long-term maintenance, most therapies would require repeated or long-term use to maintain results.
Minor surgical procedures such as gentle acne extractions may be useful in resistant keratosis pilaris. Extractions of keratotic papules and milia are performed using a small 30-gauge needle, larger 18-gauge needle, or a small diabetic lancet to pierce the overlying skin. A comedone extractor or 2 cotton-tipped applicators can be used to extract the keratin plugs or trapped coiled hairs. Best results may be achieved with combination therapy using topical emollients and physical treatments, such as manual extraction of white heads (termed acne surgery), microdermabrasion, and chemical peels.
NOTE: The above information is for processing purpose. The information provided herein should not be used during any medical emergency or for the diagnosis or treatment of any medical condition.
DISCLAIMER: This information should not substitute for seeking responsible, professional medical care.