Seborrhoic Dermatitis

Pytiriasis Sicca — Chronic inflammatory skin disorder that affects sebaceous gland–rich areas

Aetiology

  • Not fully understood, but contributing factors include:
    • Malassezia furfur/Pytirosporum ovale overgrowth
    • Excess sebum production
    • Genetic predisposition
    • Stress, fatigue, hormonal imbalance
    • Cold, dry environments
  • More severe in:
    • HIV patients
    • Neurologic disorders (e.g., Parkinson’s disease)

Clinical presentation

  • Erythematous plaques with greasy, yellowish scales
  • Itching and burning sensation may occur
notion image
  • Common sites:
    • Scalp → dandruff
    • Face (nasolabial folds, eyebrows, glabella)
    • Ears (external canal)
    • Chest, upper back (sternal area)
    • Intertriginous areas (axilla, groin)
Infant form: Cradle cap
  • Thick, greasy scales on scalp in infants, self-limiting
notion image

Investigations

  • Primarily clinical
  • Skin scrapings may be done to rule out tinea (KOH prep)
  • Biopsy rarely required

Management

First-line therapy

  • Antifungal agents
    • Ketoconazole 1-2% shampoo/2% cream (2–3 times weekly)
    • Ciclopirox 1-5% or selenium sulfide 2.5% shampoo 2-3 times weekly
  • Topical corticosteroids (low-potency)
    • Hydrocortisone 1% for facial involvement (short-term use)

Infants (Cradle cap)

  • Gentle baby shampoo
  • Emollients/olive oil to soften scales before washing
  • Mild topical antifungals if persistent