Seborrheic dermatitis !
A common, recurring skin rash with greasy yellow scales on the scalp, face and chest; in babies it is called cradle cap.
Updated 2026-11-01
Structures involved
Tap one to see what it is and open it in 3D.
Why it happens
What it is
A chronic, relapsing inflammatory skin disease of the areas rich in sebaceous glands (scalp, eyebrows, sides of the nose, ears, chest), linked to the yeast Malassezia. Dandruff is its mildest form, and cradle cap is the infant form.
Who gets it
Very common in all populations, with two peaks: infants in the first three months of life and adults from adolescence to around 50 years. More frequent in men. Much more common and severe in people with HIV infection and in Parkinson disease.
Causes
- Abnormal inflammatory response to Malassezia yeasts that live on oily skin
- Sebaceous gland activity, which is why it appears in infancy (maternal hormones) and after puberty
- Changes in the skin barrier and genetic susceptibility
Risk factors
- HIV infection, where it can be an early clue
- Parkinson disease and other neurological disorders
- Stress, fatigue, cold dry weather
- Alcohol use disorder and obesity
- Some drugs (for example certain antipsychotics and lithium)
Pathophysiology
Malassezia breaks down sebum lipids into irritating free fatty acids. In susceptible people this triggers inflammation and faster turnover of the epidermis, which gives redness and greasy scales in places where sebum is abundant.
Classification
- Infantile: cradle cap on the scalp, sometimes with folds and diaper area
- Adult: scalp (dandruff), face, ears, chest and skin folds
- Severe or widespread forms in immunosuppression
Symptoms and signs
- Greasy yellowish scales over red patches on the scalp
- Redness and scaling of the eyebrows, sides of the nose, nasolabial folds and behind the ears
- Scaling of the eyelid margins (seborrhoeic blepharitis)
- Patches on the central chest and in skin folds
- Mild itching; flares with stress and cold weather
- In infants: thick, adherent yellow crusts on the scalp that do not bother the baby
Diagnosis
- Clinical
- Diagnosis is clinical, based on the typical greasy scales in sebum-rich areas and the relapsing course.
- Tests
- Usually none. Skin scraping with potassium hydroxide to rule out tinea capitis, HIV testing for severe or sudden disease, and biopsy only when the diagnosis is doubtful.
- Imaging
- Not needed.
Differential diagnosis
- Psoriasis of the scalp (thicker, silvery, sharply demarcated plaques)
- Atopic dermatitis (especially in infants)
- Tinea capitis and tinea faciei
- Rosacea and lupus erythematosus on the face
- Contact dermatitis
Goal of treatment
Control redness, scaling and itching and reduce flares, since the condition can be controlled but not cured.
Treatment
- Medical
- Topical antifungals such as ketoconazole or ciclopirox, as shampoo for the scalp and as cream for the face and body.
- Medical
- Short courses of low-potency topical corticosteroids or topical calcineurin inhibitors for flares on the face.
- Conservative
- Medicated shampoos with zinc pyrithione, selenium sulfide or coal tar; in infants, softening the crusts with an emollient and gentle brushing.
- Lifestyle
- Regular washing, stress management and avoidance of irritating products; ongoing maintenance use of an antifungal shampoo.
Drugs for this condition
Complications
- Secondary bacterial or yeast infection
- Seborrhoeic blepharitis and eye irritation
- Skin atrophy or telangiectasia from overuse of topical corticosteroids on the face
- Psychological distress from visible facial lesions
Prognosis
Cradle cap usually clears within the first year of life. In adults the disease is chronic with flares and remissions, but it is well controlled with maintenance treatment.
Prevention
- Maintenance use of medicated or antifungal shampoo to reduce relapses
- Gentle daily hygiene of the scalp and face
Test yourself
Think of the answer, then tap the question to see it.
Which organism is linked to seborrheic dermatitis?
Malassezia yeasts.
What is the infant form called?
Cradle cap: thick yellow, greasy crusts on the scalp in the first months of life.
Which two conditions are classically associated with severe adult seborrheic dermatitis?
HIV infection and Parkinson disease.
What is the first-line treatment?
Topical antifungals such as ketoconazole shampoo or cream, with short courses of mild topical corticosteroids for flares.
Related conditions
Educational information, not medical advice. For any symptom, see a health professional.
Sources: Seborrheic dermatitis: MedlinePlus Medical Encyclopedia (MedlinePlus, US National Library of Medicine, 2026).
Spotted a mistake?We are always improving for the community. Tell us what is wrong and our team will review it.Report a mistake
Representative model, for educational purposes only.
