You are in: eMedicine Specialties > Pediatrics: General Medicine > Dermatology Keratosis PilarisArticle Last Updated: Dec 4, 2007AUTHOR AND EDITOR INFORMATIONSection 1 of 11
  Author: Mark A Crowe, MD, Assistant Clinical Instructor, Department of Medicine, Division of Dermatology, University of Washington School of Medicine Mark A Crowe is a member of the following medical societies: American Academy of Dermatology and North American Clinical Dermatologic Society Coauthor(s): Steven J Escobar, MD, Fellow, Division of Pulmonary and Critical Care Medicine, Naval Medical Center, San Diego Editors: Kevin P Connelly, DO, Clinical Assistant Professor, Department of Pediatrics, Division of General Pediatrics and Emergency Care, Virginia Commonwealth University; Medical Director, Paws for Health Pet Visitation Program; Mary L Windle, PharmD, Adjunct Assistant Professor, University of Nebraska Medical Center College of Pharmacy, Pharmacy Editor, eMedicine.com, Inc; Robert A Schwartz, MD, MPH, Professor and Head of Dermatology, Professor of Medicine, Professor of Pediatrics, Professor of Pathology, Professor of Preventive Medicine and Community Health, UMDNJ-New Jersey Medical School; Merrily P M Poth, MD, Professor, Department of Pediatrics and Neuroscience, Uniformed Services University of the Health Sciences; Dirk M Elston, MD, Director, Department of Dermatology, Geisinger Medical Center Author and Editor Disclosure Synonyms and related keywords: keratosis pilaris alba, keratosis pilaris rubra, goose bumps, hair follicle, keratinized hair follicles, keratotic papule, perifollicular erythema, ichthyosis vulgaris, atopic dermatitis, hyperandrogenism, erythematous papules, corneocyte adhesion, hyperkeratosis, hypogranulosis INTRODUCTIONSection 2 of 11
  BackgroundKeratosis pilaris is an extremely common and benign disorder of keratinized hair follicles. The disease is characterized by grouped, horny, keratotic follicular papules predominantly located on the extensor surfaces of the proximal limbs, most commonly of the posterolateral upper arms and anterior thighs. It is usually asymptomatic except for its cosmetic appearance. Treatment is marginally effective and only provides temporary relief. PathophysiologyApparently because of lack of proper desquamation of keratinocytes, the follicular orifice becomes plugged with keratin and results in a keratotic papule. A variable degree of perifollicular erythema occurs. FrequencyUnited StatesSignificant individual variation is observed in the prominence and severity of keratosis pilaris, which affects 42% of the population. Some studies estimate that keratosis pilaris affects 50-80% of all adolescents. The disorder has a familial relationship, which is consistent with autosomal dominant transmission. Frequency is increased, reported at 74%, in individuals with ichthyosis vulgaris. Many older reports claim an increased incidence with atopic dermatitis, but more recent studies do not demonstrate this association. Hormonal influence may occur because a high prevalence and intensity of keratosis pilaris is noted during puberty and in women with hyperandrogenism. InternationalIncidence is similar to that observed in the United States. Mortality/MorbidityKeratosis pilaris is a benign disorder; treatment in most cases requires simple reassurance and general skin care recommendations. Many patients find lesions cosmetically unappealing and, therefore, seek treatment. Occasionally, they may become secondarily infected because of scratchy, tight-fitting clothing or abrasive self-therapy, in which case treatment of the infection is necessary. A significant inflammatory component may be present and may be relieved with topical steroid therapy. Treatment of the noninflamed horny papules can be difficult because they have proven resistant to most modes of therapy. RaceNo evidence of racial predilection exists. SexThe inflammatory form of keratosis pilaris is more prevalent in females. AgeFifty-one percent of cases are diagnosed in people in the first decade of life, 35% in the second, 12% in the third, and 2% in the fourth. CLINICALSection 3 of 11
History
Physical
CausesEtiology is unknown, although it may be due to a disorder of corneocyte adhesion that prevents normal desquamation in the area around the follicle. DIFFERENTIALSSection 4 of 11
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| Drug Name | Ammonium lactate cream (Lac-Hydrin cream 12%) |
|---|---|
| Description | Emollient available in 225-g and 400-g bottles and promotes hydration and removal of excess keratin. Contains lactic acid, an alpha hydroxy acid that has keratolytic action, thus facilitating release of comedones. |
| Adult Dose | Apply to affected area bid/tid Application to the skin while moist after washing or bathing enhances the moisturizing effect |
| Pediatric Dose | Apply as in adults |
| Contraindications | Documented hypersensitivity |
| Interactions | None reported |
| Pregnancy | C - Fetal risk revealed in studies in animals but not established or not studied in humans; may use if benefits outweigh risk to fetus |
| Precautions | Apply hydration, moisturizers, and possibly topical corticosteroids until fissures and inflammation are reduced; transient stinging, burning, erythema, and peeling have been noted after application of ammonium lactate lotion, especially when applied to abraded, inflamed, or irritated skin |
Topically applied urea has a hygroscopic effect by increasing the water retention in skin and it decreases pruritus.
| Drug Name | Urea cream 20% (Carmol 20, Ureacin, Lanaphilic) |
|---|---|
| Description | Application of 20% urea promotes hydration and removal of excess keratin. |
| Adult Dose | Apply to affected area bid/tid Application to the skin while moist after washing or bathing enhances the moisturizing effect |
| Pediatric Dose | Apply as in adults |
| Contraindications | Documented hypersensitivity |
| Interactions | None reported with topical use |
| Pregnancy | C - Fetal risk revealed in studies in animals but not established or not studied in humans; may use if benefits outweigh risk to fetus |
| Precautions | Apply hydration, moisturizers, and possibly topical corticosteroids until fissures and inflammation are reduced; transient stinging, burning, erythema, and peeling have been noted after application of 20% urea, especially when applied to abraded, inflamed, or irritated skin |
These agents produce desquamation of the skin's horny layer. They are keratolytic at concentrations of 2-6%.
| Drug Name | Salicylic acid 6% (Keralyt gel) |
|---|---|
| Description | Removes excess keratin. |
| Adult Dose | Apply a thin layer to affected area qd/bid |
| Pediatric Dose | Apply as in adults |
| Contraindications | Documented hypersensitivity; prolonged use in infants, patients with diabetes mellitus, and patients with impaired circulation (not recommended); use on moles, birthmarks or warts with hair growing from them, genital or facial warts or warts on mucous membranes, irritated skin, or any area infected or reddened |
| Interactions | None reported |
| Pregnancy | C - Fetal risk revealed in studies in animals but not established or not studied in humans; may use if benefits outweigh risk to fetus |
| Precautions | Burning and irritation at site of exposure may occur; avoid contact with mucous membranes and eyes; prolonged use over large areas, especially in children, may result in salicylate toxicity |
Retinoic acid decreases cohesiveness of follicular epithelial cells, stimulates mitotic activity, and increases turnover of follicular epithelial cells.
| Drug Name | Tretinoin (Retin-A 0.025% - 0.1% cream) |
|---|---|
| Description | Reduces cohesion among keratinized cells. |
| Adult Dose | Begin with lowest tretinoin concentration and increase as tolerated; apply hs or qod; decrease application frequency if irritation develops |
| Pediatric Dose | Apply as in adults |
| Contraindications | Documented hypersensitivity |
| Interactions | Toxicity increases with coadministration of benzoyl peroxide, salicylic acid, and resorcinol; avoid topical sulfur, resorcinol, salicylic acid, other keratolytics, abrasives, astringents, spices, and lime |
| Pregnancy | C - Fetal risk revealed in studies in animals but not established or not studied in humans; may use if benefits outweigh risk to fetus |
| Precautions | Photosensitivity may occur with excessive sunlight exposure, wear sunscreen over exposed areas; during the first few wk, the patient may experience redness, burning, or peeling; most patients adapt to treatment; switch those who become excessively irritated to qod or q3d therapy; do not apply to mucous membranes, mouth, and angles of nose |
These agents elicit anti-inflammatory and immunosuppressive properties.
| Drug Name | Triamcinolone acetonide 0.1% cream (Aristocort, Kenalog) |
|---|---|
| Description | A moderate-potency steroid with anti-inflammatory properties. It treats inflammatory dermatosis that is responsive to steroids. It decreases inflammation by suppressing the migration of polymorphonuclear leukocytes and reversing capillary permeability. |
| Adult Dose | Apply sparingly to affected areas qd/bid until inflammatory component begins to resolve (typically 7 d) |
| Pediatric Dose | Apply as in adults with caution |
| Contraindications | Documented hypersensitivity; fungal, viral, and bacterial skin infections |
| Interactions | None reported |
| Pregnancy | C - Fetal risk revealed in studies in animals but not established or not studied in humans; may use if benefits outweigh risk to fetus |
| Precautions | As with all topical corticosteroids, skin atrophy with telangiectasia, stria, purpura, and acne may occur; limit the use of topical steroids to the initial inflammatory treatment phase; long-term use of topical corticosteroids has no role in keratosis pilaris; limit tube size to reflect area and duration of treatment; do not use in decreased skin circulation; prolonged use, applications over large areas, and use of potent steroids and occlusive dressings may result in systemic absorption; systemic absorption may cause Cushing syndrome, reversible HPA axis suppression, hyperglycemia, and glycosuria |
A 1994 study performed by Poskitt demonstrates the following course:1
| Media file 1: Although other sites may be involved, keratosis pilaris is most common on the lateral upper arms and upper thighs. | |
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| Media file 2: Upon closer examination of keratosis pilaris, the lesions are very evenly spaced. This even distribution is consistent with the follicular origin of this disorder. | |
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| Media file 3: Close examination of keratosis pilaris shows keratotic papules associated with hair follicles. Keratinocytes normally shed from the surrounding skin become dust on the floor. Keratinocytes at the follicular orifice are retained, producing these papules. | |
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| Media file 4: Bacteria associated with the follicular papules of keratosis pilaris may cause some lesions to become erythematous or pustular. | |
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| Media file 5: This patient has lichen nitidus. Lichen nitidus is a differential diagnosis for keratosis pilaris. The papules of lichen nitidus tend to be flatter, and lesions develop in crops. Etiology of lichen nitidus is unknown. | |
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| Media file 6: Lichen nitidus also shows the property of koebnerization. Keratosis pilaris does not koebnerize. | |
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| Media file 7: Disseminate and recurrent infundibulofolliculitis is an uncommon slightly pruritic papular follicular eruption that affects the neck, face, trunk, and proximal extremities. It is a differential diagnosis for keratosis pilaris and occurs almost exclusively in blacks. The cause is unknown, and treatment has been totally unsuccessful. Disseminate and recurrent infundibulofolliculitis differs from keratosis pilaris in distribution and is less keratotic. | |
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Article Last Updated: Dec 4, 2007
