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: infancy (1), adolescence (2), and adulthood
• Predominant sex: male > female

Prevalence

• Seborrheic dermatitis: 1–3%; in immunosuppressed individuals up to 83% (2)
• Infantile seborrheic dermatitis: up to 71% in the first 3 months of life, all ethnicities, all climates (1)

Etiology and Pathophysiology

• Skin surface yeast such as Malassezia may be a contributing factor (3).
• 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.
• Seborrheic dermatitis 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 (3).

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

Risk Factors

• Immunosuppressed conditions such as AIDS, lymphoma, organ transplantation (2),(4)
• Parkinson disease, epilepsy, traumatic brain, and spinal cord injury (4)
• Emotional stress (2)
• Obesity (2)
• Oily skin (2)
• Acne (2)
• Medications may cause flares/induce seborrheic dermatitis: buspirone, chlorpromazine, cimetidine, ethionamide, griseofulvin, haloperidol, interferon-α, methyldopa, psoralen, IL-2 (2)

General Prevention

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

Commonly Associated Conditions

• Parkinson disease
• AIDS