Seborrhoeic Dermatitis is a chronic, relapsing skin condition caused by an abnormal inflammatory response to skin yeasts (especially Malassezia species).
It is common, affecting up to 5% of adults, and is usually mild but can be distressing due to itching and cosmetic impact.
Antifungal creams and medicated shampoos are the mainstay of long-term management and are safe for repeated use.

🧬 Aetiology

Strongly associated with the yeast Pityrosporum ovale (Malassezia), which thrives in sebaceous (oily) areas.
More severe in patients with Parkinson’s disease and HIV, due to altered immune responses.
May also be worsened by genetic susceptibility, environmental stress, or cold weather.

👀 Clinical Features

Dry, scaly, flaky rash with erythema, often itchy.
Commonly affects:
- Eyebrows & nasolabial folds
- External ears & ear canals
- Scalp (dandruff or thick crusting)
- Chest and sternum
Worsens in stress or winter.
Unilateral distribution may occur in stroke patients due to altered skin innervation.

Seborrhoeic dermatitis image

Seborrhoeic dermatitis scalp

🔗 Associations

Parkinson’s disease – thought to relate to autonomic dysfunction and excess sebum production.
HIV infection – often more severe, refractory, and widespread.
Stroke – can affect the scalp unilaterally on the side of neurological deficit.

🧪 Investigations

Diagnosis is clinical, based on rash distribution and appearance.
Skin scrapings/mycology if tinea capitis suspected.
HIV testing if seborrhoeic dermatitis is severe or atypical.

🩺 Differential Diagnosis

Psoriasis – thicker, silvery-white scales; usually spares the face.
Tinea capitis – patchy hair loss, positive fungal microscopy.
Atopic dermatitis – flexural distribution, more pruritic.
Contact dermatitis – clear exposure trigger.

💊 Management

General: Chronic relapsing course, requires maintenance therapy.
Scalp:
- Anti-dandruff shampoos: ketoconazole, selenium sulphide, or zinc pyrithione.
- Leave shampoo on for 5–10 minutes before rinsing.
- Descaling: coconut oil or salicylic acid overnight for thick crusts.
- Short-term mild steroid scalp lotion/gel for inflamed cases.
Face/Body:
- Topical antifungals: clotrimazole, miconazole, ketoconazole.
- Short course of mild topical steroids if significant erythema.
- Moisturisers to reduce scaling and redness.
Ear canals: Medicated antifungal/steroid eardrops; avoid cotton buds.
Eyelids: Gentle cleansing with diluted baby shampoo or eyelid wipes.
Refractory/widespread cases: Short oral antifungal course (e.g., itraconazole) may be considered.
Maintenance: Weekly antifungal shampoo once clear.

The content on this website is provided for educational and informational purposes only to support exam preparation (e.g., MLA, MRCP, USMLE) and learning. This is NOT medical advice, diagnosis, treatment, or professional guidance. It does not replace consultation with a qualified healthcare professional, official guidelines (e.g., NICE, GMC, BNF), or supervised clinical practice. Always verify information with current, authoritative sources. Makindo and its contributors accept no liability for any reliance on this content, including errors, omissions, or any resulting harm, loss, or consequences. By using this site, you agree to these terms.

Seborrheic Dermatitis

📖 About