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InflammatoryCommonICD-10 L21.x

Seborrhoeic dermatitis

Seborrhoea · pityriasis capitis (cradle cap, infantile) · sebopsoriasis (overlap)

Seborrhoeic dermatitis is a very common chronic inflammatory dermatosis affecting up to 5% of UK adults. Malassezia spp. yeasts trigger inflammation in sebum-rich areas — scalp, eyebrows, nasolabial folds, ears, presternal chest. There are bimodal peaks in infancy (cradle cap) and adulthood (20-50 years). Severe / refractory disease is associated with HIV, Parkinson disease, depression, neurological disorders and immune-checkpoint inhibitor therapy. Skin-oncology relevance: ICI exacerbation, common DDx for rosacea / psoriasis / mycosis fungoides.

CurrentLast reviewed 16 May 2026
Clinical image of Seborrhoeic dermatitis
Seborrhoeic dermatitis. Image sourced from DermNet New Zealand. Used under CC BY-NC-ND 4.0. No endorsement implied.

Pathogenesis

  • Malassezia spp. (M. globosa, M. restricta, M. furfur) lipase activity → free fatty acids → inflammation.
  • Sebum-rich (sebaceous) areas affected.
  • Bimodal: infantile (cradle cap) age <3 months and adult (20-50 years).
  • Risk factors:
    • HIV (severity correlates with CD4 count).
    • Parkinson disease, dementia, stroke (decreased facial movement).
    • Depression, fatigue.
    • Immune-checkpoint inhibitors (PD-1, CTLA-4).
    • Cold dry weather; reduced sun exposure.

Clinical features

  • Adult: erythematous patches with greasy yellow scale; symmetrical:
    • Scalp (commonest — dandruff).
    • Eyebrows, glabella, nasolabial folds.
    • External auditory meatus (otitis externa form).
    • Preauricular / postauricular.
    • Beard.
    • Pre-sternal, interscapular, axillary, groin.
  • Infantile: yellow greasy scale on scalp (cradle cap); flexural; resolves within months.
  • HIV-associated: severe, atypical distribution, recurrent; check CD4.
  • Pruritus mild; cosmetic distress is main concern.
  • Sebopsoriasis: overlap with psoriasis (sharply demarcated, silvery scale, extensor distribution).

Differentials

  • Psoriasis — silvery scale, sharper demarcation, extensor distribution, nail involvement.
  • Rosacea — central face, telangiectasia, papulopustules.
  • Atopic eczema — flexural, atopic background.
  • Tinea capitis / faciei — annular advancing edge; KOH+.
  • Contact dermatitis — geometric, exposure-related.
  • Mycosis fungoides — chronic, asymmetric, fixed plaques.
  • Lupus erythematosus — sun-exposed, autoantibodies.
  • Pityriasis rosea — herald patch, self-limiting.
  • Histiocytosis — paediatric severe scalp.

Management

  • Scalp:
    • Ketoconazole 2% shampoo BD-QDS for 2 weeks; then 1-2× weekly maintenance.
    • Selenium sulfide 2.5% shampoo.
    • Zinc pyrithione shampoo.
    • Salicylic acid / coal tar shampoo for thick scale.
    • Ciclopirox 1.5% shampoo.
    • Short-course topical corticosteroid lotion / mousse for severe flares (mometasone, betamethasone valerate).
  • Face / body:
    • Ketoconazole 2% cream, ciclopirox 1% cream, miconazole.
    • Mild-potency topical corticosteroid (hydrocortisone 1% / clobetasone butyrate) for 1-2 weeks.
    • Topical calcineurin inhibitors (pimecrolimus, tacrolimus) — steroid-sparing for face.
  • Infantile: emollients; ketoconazole shampoo gently; usually resolves spontaneously by 6-12 months.
  • Severe / refractory:
    • Oral antifungals: itraconazole 200 mg OD for 7 days then maintenance; fluconazole.
    • HIV testing if severe / atypical.
  • Counsel:
    • Chronic-relapsing course; maintenance therapy expected.
    • Improves with sun exposure (but counsel on photoprotection for skin cancer).
    • Stress, fatigue, dry climate are triggers.

References

  1. Gupta AK, Bluhm R. Seborrheic dermatitis. J Eur Acad Dermatol Venereol. 2004;18:13-26.
  2. Naldi L, Rebora A. Clinical practice. Seborrheic dermatitis. N Engl J Med. 2009;360:387-396.
  3. NICE CKS. Seborrhoeic dermatitis. London: NICE; accessed 18 May 2026.
  4. Borda LJ, Wikramanayake TC. Seborrheic dermatitis and dandruff: a comprehensive review. J Clin Investig Dermatol. 2015;3:10.
  5. Sibaud V et al. Dermatologic complications of anti-PD-1/PD-L1 immune checkpoint antibodies. Curr Opin Oncol. 2016;28:254-263.

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