Dandruff and seborrheic dermatitis are often confused — they share symptoms, have overlapping causes, and are treated with many of the same ingredients. But they're not quite the same condition.
What Is Dandruff?
Dandruff (pityriasis capitis) is a common, mild scalp condition characterised by white or grey flakes and occasional itching. It's primarily caused by the overgrowth of Malassezia, a yeast that naturally lives on the scalp. Dandruff is limited to the scalp and is generally not significantly inflammatory.
What Is Seborrheic Dermatitis?
Seborrheic dermatitis is a more complex inflammatory skin condition. It can affect the scalp, but also commonly appears on the face — around the eyebrows, nose, and ears — as well as the chest. In addition to flaking, it causes visible redness, oily or yellowish scale, and more intense itching. It tends to be chronic, flaring and remitting with triggers like stress, cold weather, and hormonal shifts.
The Shared Cause
Both conditions involve Malassezia and both are influenced by sebum production. This is why the same antifungal ingredients — ketoconazole, zinc pyrithione, selenium sulfide — are effective for both.
How to Tell Them Apart
Flaking limited to the scalp with no significant redness? Likely dandruff. Redness, flaking extending to the face or other body areas, or symptoms that have persisted for months? Seborrheic dermatitis is more probable.
When to See a Dermatologist
For mild cases, over-the-counter medicated shampoos are usually sufficient. For moderate to severe seborrheic dermatitis — particularly when it involves facial skin — a dermatologist can prescribe stronger treatments.