Dermatitis, Seborrheic

BASICS

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

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