Dermatitis, Seborrheic

Description

Chronic, superficial, recurrent inflammatory skin disorder affecting sebum-rich, hairy regions of the body, especially the scalp, eyebrows, and face and to lesser extent, chest, and back

Epidemiology

Incidence

• Predominant age: adolescence, followed by infancy and adulthood (1)
• Predominant sex: male > female

Prevalence

• Affects 2–5% of the global population; up to 83% in immunosuppressed, HIV-positive individuals (2)
• Infantile seborrheic dermatitis (SD) is common in the first 3 months of life, affecting all ethnicities in all climates.

Etiology and Pathophysiology

• Skin surface yeast such as Malassezia may be a contributing factor.
• Genetic and environmental factors: Flares are common with stress/illness.
• Parallels increased sebaceous gland activity in infancy and adolescence or as a result of some acnegenic drugs.
• SD is more common in immunosuppressed patients, suggesting that immune mechanisms are implicated in the pathogenesis of the disease, although the mechanisms are not well-defined.

Genetics
Positive family history; no genetic markers have been identified to date.

Risk Factors

• Immunosuppressed conditions such as HIV/AIDS (2)
• Parkinson disease, neurologic disorders, facial paralysis (1)
• Emotional stress (2)
• Obesity (2)
• Oily skin (2)
• Acne (2)
• Down syndrome (1)
• Medications may cause flares/induce SD: buspirone, chlorpromazine, cimetidine, ethionamide, griseofulvin, haloperidol, interferon-α, methyldopa, psoralen, and IL-2 (2).

General Prevention

Seborrheic skin should be washed more often than usual to soften the affected areas.

Commonly Associated Conditions

• Parkinson disease
• HIV/AIDS
• Facial paralysis
• Down syndrome