FFinalistSouthampton · 2027
Dermatology
AKT · Dermatology/Inflammatory & papulosquamous

Seborrhoeic dermatitis

Inflammatory reaction to Malassezia yeast in sebaceous areas

Overview

A common chronic, relapsing inflammatory dermatitis of the sebaceous-rich areas (scalp, face, central chest), driven by an inflammatory response to commensal Malassezia yeast. Infantile form = cradle cap. Florid or sudden severe disease is a flag for HIV/Parkinson disease.

Recognise

  • Ill-defined erythema with greasy yellowish scale in the nasolabial folds, eyebrows, scalp (dandruff), ears and central chest
  • Chronic and relapsing, worse with stress and in winter
  • Infantile: cradle cap (scalp) and a napkin/flexural eruption

Red flags

  • Sudden severe or treatment-resistant seborrhoeic dermatitis → consider HIV; also more common/severe in Parkinson disease and other neurological conditions

Differentials & how to tell them apart

Psoriasiswell-demarcated silvery plaques on extensors/scalp margin — seborrhoeic dermatitis is ill-defined with greasy scale in the folds
Atopic eczemaflexural, intensely itchy, atopy history
Rosaceacentral-face papulopustules + telangiectasia, no greasy scale
Tinea/contact dermatitisKOH or contact history

Clinical image

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Seborrhoeic dermatitis — clinical imagesDermNet

Investigations

Clinical diagnosis. Consider HIV testing if unusually severe, extensive or resistant.

Management

Topical antifungal (ketoconazole) ± a short mild topical corticosteroid for flares

  1. 1Antifungal (ketoconazole shampoo as a scalp/face wash or cream) ± a short course of mild topical corticosteroid for inflamed flares; emollients/medicated shampoo for maintenance.Gate: Sudden, severe or treatment-resistant seborrhoeic dermatitis should prompt consideration of HIV (and it is more florid in Parkinson disease) — the severity is the clue to look beyond the skin
  2. 2Chronic relapsing disease → intermittent antifungal maintenance; facial disease → calcineurin inhibitor to spare steroids. Cradle cap → emollient/soft brushing ± antifungal.
Antifungal (ketoconazole shampoo/cream) — first-line — targets Malassezia (scalp and face)
Mild topical corticosteroid — short courses for inflamed flares (face/folds)
Topical calcineurin inhibitor — steroid-sparing for facial disease
Emollients / regular medicated shampoo — maintenance

Key points

It is an inflammatory reaction to yeast, hence antifungal first-line (not just steroid). Florid disease is a recognised HIV and Parkinson association.

Monitor & prognosis

Relapse control.

Chronic and relapsing but readily controlled.

Source: NICE CKS Seborrhoeic dermatitis; DermNet