Seborrheic dermatitis

Seborrheic dermatitis is a common chronic inflammatory skin condition that affects areas with a high concentration of sebaceous glands (e.g., scalp, face). The etiology is unknown, but microbial colonization of the skin (esp. Malassezia species), hormonal and immunological factors, and climate have been implicated. Seborrheic dermatitis typically manifests as erythematous patches or plaques with overlying scaling or greasy yellow crusts. Symptoms include burning and/or itching. Diagnosis is clinical. Treatment typically begins with topical antifungal agents; depending on severity and areas of involvement, other topical and/or systemic anti-inflammatory agents may be used. Ongoing management of seborrheic dermatitis may include pharmacotherapy to prevent disease flares.

Infantile seborrheic dermatitis (cradle cap) is a subtype of seborrheic dermatitis that appears within the first 3 months after birth and often affects the scalp. Infantile seborrheic dermatitis usually resolves without intervention by 12 months of age.

• Sex: ♂ > ♀ ^[1]
• Bimodal distribution: infants from within the first 3 months to 12 months; puberty and early adulthood ^[2]
• Prevalence: approximately 2–5% of general population worldwide ^[1][3]

Epidemiological data refers to the US, unless otherwise specified.

• Unknown etiology; may be associated with Malassezia species
• Predisposing factors
  • Parkinson disease
  • Immunodeficiency (e.g., HIV infection)
  • Oily skin (seborrhea)
  • Androgenetic alopecia
  • Familial history of seborrheic dermatitis, psoriasis

References:^[4][5][6]

• The pathophysiology is not yet fully understood.
  • Colonization of the yeast Malassezia furfur (previously known as Pityrosporum ovale) in areas with sebaceous glands
  • Inadequate or abnormal immune response to Malassezia ) and/or exposure to irritants (toxin production or lipase activity)
  • Subsequent inflammatory reaction of the skin (the sebaceous glands themselves are not typically inflamed)
• Endogenous precipitants; : psychological stress; , fatigue, sleep deprivation, and hormonal changes
• Exogenous precipitants; : climate (the condition improves in the summer months and worsens in winter; ), trauma (e.g., excoriation of the skin from scratching), medication

References:^[4][5][6][7]

The following applies to adults and adolescents. See “Special patient groups” for features of infantile seborrheic dermatitis. ^[3][8]

• Course: chronic, with episodic flares
• Appearance
  • Erythematous patches or plaques with:
    • Scaling
    • Greasy yellow crusts
    • Flaking (e.g., dandruff on scalp)
  • Hyperpigmentation or hypopigmentation ^[3]
• Distribution: areas with; a high concentration of sebaceous glands, such as hairy and oily skin
• Locations
  • Scalp
  • Face
    • Forehead, hairline, and retroauricular area
    • Cheeks
    • Nasolabial fold
    • Eyebrows and periocular region (may be associated with blepharitis) ^[9]
  • Trunk (e.g., chest and back)
  • Intertriginous areas (e.g., axillae, under breasts, groin) ^[10]
• Symptoms: itching and burning ^[10]

Patients with dark skin tones may present with hypopigmentation, without erythema, and with less scaling than patients with light skin tones. ^[3]

• Diagnosis is clinical. ^[8]
• Diagnostic uncertainty: Obtain skin biopsy. ^[8]
• Severe, extensive, and/or refractory disease: Consider evaluation for underlying medical conditions. ^[3][10]
  • Immunocompromising conditions (e.g., HIV) ^[11]
  • Neurologic conditions (e.g., Parkinson disease, stroke)

• See “Rash.”
• See “Differential diagnosis of scaling” in “Psoriasis.”
• Atopic dermatitis: Lesions are usually dry (rather than greasy) and often occur on flexural surfaces. ^[12]
• Contact dermatitis (e.g., allergic contact dermatitis, irritant contact dermatitis): The rash distribution reflects the areas and shapes of external exposure. ^[8]
• Dermatophyte infections: Tinea corporis lesions are typically annular with central clearing; tinea capitis typically involves alopecia and broken hair shafts. ^[13]
• Rosacea: erythematous papular and pustular lesions across chin, forehead, cheeks, and nose ^[14]
• Candidiasis: typically occurs in intertriginous areas and on mucosal surfaces; characteristic satellite lesions on skin ^[15]

The differential diagnoses listed here are not exhaustive.

Goals of management are to reduce active lesions, mitigate symptoms, and prevent disease flares. ^[3][8]

Approach ^[3][8][16]

• Advise avoiding precipitating factors, if possible (e.g., stress). ^[9]
• Initiate treatment for active seborrheic dermatitis based on severity and areas of involvement.
  • All patients: topical antifungals (e.g., ketoconazole, selenium sulfide shampoo, zinc pyrithione shampoo)
  • Moderate to severe disease: Consider a short course of topical corticosteroids (e.g., up to 4 weeks) in addition to antifungals. ^[17]
  • Widespread disease: Refer to dermatology for consideration of systemic therapy.
• Assess response to treatment after 2–8 weeks.
  • If active disease is resolved, initiate ongoing management of seborrheic dermatitis.
  • For persistent or worsening symptoms, consider:
    • Addition of a topical corticosteroid (if not yet tried)
    • Treatment of refractory seborrheic dermatitis (including, e.g., referral to dermatology for consideration of systemic therapy)

Exposure to sunlight reduces symptoms in some individuals and precipitates symptoms in others. ^[9]

Treatment of active seborrheic dermatitis ^[3][8][16]

Initial treatment

Topical antifungal therapy is the first-line treatment for seborrheic dermatitis affecting the scalp, face, and/or body. ^[8]

Topical corticosteroid use should be intermittent and limited to 2–4 weeks at a time to reduce the risk of adverse effects (e.g., atrophy, hypopigmentation). ^[8]

Treatment of refractory seborrheic dermatitis

• Topical
  • Calcineurin inhibitors: only used for nonscalp disease
    • Pimecrolimus (off-label) ^[8]
    • Tacrolimus (off-label) ^[8]
  • Roflumilast ^[18]
• Systemic
  • Systemic antifungals
  • Isotretinoin

Ongoing management of seborrheic dermatitis

• Prevention of flares
  • Scalp dermatitis: Consider weekly use of topical antifungal shampoo (e.g., ketoconazole, ciclopirox). ^[8]
  • Face and/or body seborrheic dermatitis: topical ketoconazole as needed (up to once daily) ^[8][17]
• Treatment of acute flares: See “Treatment of active seborrheic dermatitis.”

Seborrheic dermatitis is a chronic disease; long-term management involves maintenance therapy to reduce the risk of disease flares and acute treatment as needed. ^[3][8]

• Exacerbation of seborrheic dermatitis may lead to generalized erythroderma.
• Secondary bacterial infection

We list the most important complications. The selection is not exhaustive.

Seborrheic dermatitis often has a chronic, recurrent course with flares requiring intermittent treatment. ^[8]

Infantile seborrheic dermatitis ^[2][8]

• Onset: typically within the first 3 months after birth ^[2]
• Clinical features
  • Appearance: Erythematous (or salmon-colored) patches with greasy, yellow, adherent scales
  • Location:
    • Scalp (common; also known as cradle cap)
    • Face (e.g., forehead, nose, retroauricular area) ^[3]
    • Intertriginous areas (e.g., neck, diaper area)
• Subtypes and variants: desquamative erythroderma (Leiner disease) ; ^[19]
  • Most severe form of infantile seborrheic dermatitis
  • Clinical features include erythroderma, recurrent diarrhea, and failure to thrive.
• Diagnosis: clinical ^[8]
• Differential diagnoses
  • Atopic dermatitis: Lesions are usually dry (rather than greasy). ^[12]
  • Diaper dermatitis; (due to allergic contact dermatitis or irritant contact dermatitis): usually spares intertriginous areas ^[20]
• Treatment: typically unnecessary
  • Counsel parents that:
    • The condition is benign.
    • Most seborrheic dermatitis resolves spontaneously by 1 year of age. ^[2]
  • If desired, scales can be removed by:
    • Frequent washing with baby shampoo and/or applying softener (e.g., petroleum jelly, mineral oil) to scalp
    • Gently scrubbing or combing to remove softened scales
  • For refractory infantile seborrheic dermatitis, consider ketoconazole (off-label). ^[2][8]
• Complications: (rare): erythroderma ^[21]