Is seborrheic dermatitis fungal?

What role does yeast play?

Malassezia is part of the skin's normal community of microorganisms. In seborrheic dermatitis, the yeast appears to set off an immune response that contributes to redness, itching and scaling. The full cause is not understood, so describing the condition as just 'too much fungus' misses the inflammatory part. Antifungals reduce the yeast population; medicines that reduce inflammation address another part of the problem.1

Is it the same as ringworm or fungal acne?

Malassezia is associated with both seborrheic dermatitis and Malassezia folliculitis, so the yeast's name alone is a poor filing system.4

Scalp ringworm can spread through contact with people or shared hats, combs and hair accessories. It needs prescription antifungal medicine. Patches of hair loss or broken hairs are reasons to get a diagnosis rather than keep treating the problem as ordinary dandruff.5

Does dandruff mean you have a fungal infection?

Dandruff is an uninflamed form of seborrheic dermatitis on the scalp. But flakes can also come from a dry scalp, where the skin has lost too much moisture. Both can itch, and appearance alone can be difficult to interpret. Flakes describe what comes off your scalp, not why it happened, which is a disappointing amount of paperwork for shampoo.23

Hair products that strip natural oils, cold weather and low humidity can contribute to scalp dryness. Dandruff usually improves with dandruff shampoo; a dry scalp can improve with a gentle, nonmedicated shampoo. If a hair product causes irritation, stop using that product. If changing products does not help, a dermatologist can distinguish dryness from seborrheic dermatitis and other scalp conditions.35

How is seborrheic dermatitis treated?

• For the scalp, medicated shampoos include ketoconazole, ciclopirox, selenium sulfide or zinc pyrithione. A common schedule is twice weekly for at least a month, with continued use when needed.
• For the face, ears, chest or back, cleanse once or twice daily with a cleanser without soap. Ketoconazole or ciclopirox cream is commonly applied once daily for 2 to 4 weeks.
• For an inflamed flare, a clinician can add a short course of a mild topical corticosteroid. Frequent facial steroid use needs review because prolonged use can thin skin.

In adults, seborrheic dermatitis commonly returns, and maintenance treatment is often needed. Treatment aims to reduce visible scaling, itching and redness rather than permanently eliminate every yeast living on skin. Stress and cold, dry conditions can make symptoms worse.1

What about cradle cap?

Cradle cap is seborrheic dermatitis in babies and usually goes away on its own after a few months. Daily washing with mild baby shampoo and gentle rubbing with fingers or a soft brush can help remove scales. Severe cases need a healthcare provider's advice about a prescription shampoo or cream.7

When should you see a doctor?

Arrange an assessment if dandruff treatments do not help, itching is constant, or the scalp becomes swollen, warm or painful. Seborrheic dermatitis is usually diagnosed from the rash's appearance, location and behaviour. Finding Malassezia in a skin scraping alone does not confirm the diagnosis because the yeast normally lives on skin.235