Seborrheic dermatitis is a common, recurring rash with greasy yellow scale in areas rich in oil glands, such as the scalp, eyebrows and sides of the nose. It is linked to an inflammatory response to a yeast that normally lives on the skin and is called cradle cap in babies.
Key symptoms
- Dandruff and flaking of the scalp
- Red, itchy patches with scale on the face, ears or chest
- Flares with stress, cold weather or illness
- In infants, thick yellow crusts on the scalp
What you find on exam
- Pink or red patches with greasy yellow scale
- Typical sites: scalp, eyebrows, nasolabial folds, behind the ears, central chest
- Scaling of the eyelid margins (blepharitis)
- Look for features of psoriasis such as nail pitting or thick silvery plaques
Tests
- Diagnosis is clinical, based on the look and location
- Skin scraping with KOH if tinea is possible
- HIV test if the rash is sudden, severe or widespread
Treatment basics
- Antifungal shampoo with ketoconazole, selenium sulfide or zinc pyrithione
- Ketoconazole cream for the face and body
- Short courses of a low-potency corticosteroid such as hydrocortisone for flares
- Topical calcineurin inhibitors such as pimecrolimus for the face
- Infants: gentle washing, emollient and soft brushing of the scale
Red flags
- Sudden, severe or widespread rash, especially in a young adult (check HIV)
- Red skin over most of the body or signs of infection
- Infant with rash plus poor feeding, poor growth or petechiae
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Sources: NCCPA PANCE Content Blueprint; NBOME COMLEX-USA clinical presentations; AAMC Core Entrustable Professional Activities (Core EPAs). Written by Making Synapses. Making Synapses is not affiliated with these organizations.