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Keratosis Pilaris

Key Points

  • Keratosis pilaris (KP) is a common, often autosomal dominantly inherited benign disorder that presents with hyperkeratotic papules with a central spicule on facial cheeks, upper posterior arms, lateral thighs, and buttocks.
  • KP often presents in association with atopic dermatitis.
  • Facial and upper arm involvement may present a cosmetic problem for patients. Frictional folliculitis arising from areas of KP may result in increased erythema or pustules in the affected area.
  • Long-term management to reduce hyperkeratosis is the mainstay of the therapeutic strategy and sometimes improves cosmetic appearance. Several treatments reduce inflammation of KP lesions.

Introduction

Keratosis pilaris (KP) is an extremely common, often autosomal dominantly inherited disorder that usually does not require treatment. Keratosis pilaris is most frequently seen in association with atopic dermatitis. The classic skin lesions are small, monomorphous, hyperkeratotic papules with a central spicule, often with an erythematous base or overlying an erythematous patch. On biopsy, these lesions are characterized by keratinous follicular plugging with orthohyperkeratosis to create a follicular spicule. Typical sites of involvement include facial cheeks, upper posterior arms, lateral thighs, and buttocks, and involvement is almost always bilateral and symmetric. Involvement of the face and upper arms may be a significant cosmetic problem for patients, and frictional folliculitis can complicate KP on the buttocks and thighs. Folliculitis may present as development of increased erythema or pustules in the affected area. Since KP is a benign and non-curable skin condition, long-term management is the mainstay of the therapeutic strategy; cosmetic improvement and reduction of inflammation are the primary therapeutic goals.

Initial Evaluation

Keratosis pilaris

Lichen spinulosus

Lichen spinulosus, a condition often seen in children, likely represents a clinical variant of KP in which typical lesions seen in KP (e.g., monomorphous hyperkeratotic papules with a central spicule) are arranged in nummular patches at sites not typically affected by KP. Hyperpigmentation of the papules or hyperkeratotic plug is common.

Differential diagnosis

Atopic dermatitis

Treatment

First-line therapy: Educate patients so that they understand that KP is not curable and that any therapeutic option only minimizes but does not eradicate the clinical lesions. Long-term management improves and maintains the cosmetic appearance of skin lesions and interventions to reduce inflammation are outlined below.

Initial therapy

  • A mild soap (e.g., Dove) or a soapless cleanser (e.g., Cetaphil, Cerave) should be used with a mild exfoliating scrub pad or washcloth. This treatment will gradually remove follicular plugs (over several weeks) and prevent new ones from emerging.
  • Salicylic acid 6% lotion (e.g., Keralyt gel) should be applied q.h.s. or after bathing. This therapy is particularly effective when used in conjunction with mechanical exfoliation (see above).
  • Urea creams or lotions in concentrations of 10 to 20% (e.g., Carmol) may be effective, and can be tolerated by many patients with atopic dermatitis.
  • Ammonium lactate 12% lotion (e.g., LacHydrin or Amlactin) applied once daily after bathing is also effective for KP. It may be combined with urea.
  • Individuals with atopic disease tend to tolerate high concentrations of lactic acid (>5%) without some adjunctive therapy to control their atopic condition. Alternatively, lower concentrations of lactic acid or combinations of lactic acid and urea may be considered.
  • There is evidence that ointment-based emollients (such as petrolatum or Aquaphor ointment) may be sufficient to improve the cosmetic appearance of KP.
  • Topical medium strength corticosteroids (e.g., triamcinolone 0.1% lotion, cream, or ointment) or tacrolimus 0.1% ointment (e.g., Protopic) may be effective in KP associated with atopic dermatitis, but are best utilized for flares of inflammatory KP and not for chronic use.
  • If highly inflammatory lesions are present, an empiric trial of erythromycin or dicloxacillin 250 mg q.i.d. for 10 days may reduce erythema and pustule formation.

Subsequent therapy

  • After the keratinous plugs have been removed, use of an emollient cream containing 20% urea (Carmol) may prevent reappearance of lesions.
  • Use of the abrasive scrub pad should be resumed at the first sign of reappearance of crops of new lesions.
  • Patient education on gentle skin care, including discussion of bathing, mild soaps, and lubrication also should be taught; KP is almost invariably associated with xerosis, and xerosis may, in fact, predispose to exacerbations of KP. (See handout Skin Care in Atopic Dermatitis.)

When to refer to a dermatologist

  • If the diagnosis of KP is not clear
  • For severe facial involvement
  • For widespread involvement of KP, or for management of generalized atopic dermatitis in the setting of KP

Clinical Case

Case 1

  • 18-year-old healthy female
  • Family history notable for atopic dermatitis and allergic rhinitis
  • Presents for evaluation and management of long-standing “rash” on bilateral posterior arms
  • Asymptomatic rash
  • Primary concern is cosmetic appearance

Initial evaluation

  • Healthy female
  • Generalized xerosis
  • Bilateral posterior arms: monomorphous, closely set 1 mm hyperkeratotic non-inflammatory papules with a central spicule overlying a faintly erythematous patch
  • No pustules present
  • Diagnosis: KP, non-inflammatory
  • Recommendation: mechanical exfoliation with washcloth daily in the shower, followed by daily application of 20% urea cream
  • Gentle skin care reviewed and educational handout provided to patient
  • Follow-up as needed

References

Breithaupt AD, Alio A, Friedlander SF (2011) A comparative trial comparing the efficacy of tacrolimus 0.1% ointment with Aquaphor ointment for the treatment of keratosis pilaris, Ped Derm, 28(4):459-477.

Marqueling A, Gilliam AE, Prendiville J, Zvulunov A, et al (2006) Keratosis pilaris rubra: a common but underrecognized condition, Arch Derm, 142:1611-1616.