Dandruff and seborrheic dermatitis sit on one inflammatory spectrum driven in part by yeast and oil. Intensity and how far it spreads, not two unrelated diseases, is the usual distinction.
Dandruff (pityriasis capitis) means flaking on the scalp without much redness. Seborrheic dermatitis adds erythema and greasy, yellowish scale and can involve eyebrows, sides of the nose, ears, and chest. Malassezia yeast and sebum play a role; it is not poor hygiene as a moral failing, though infrequent washing can let scale build. It can itch. Scratching and scale can increase breakage so hair looks thinner even when follicles are not miniaturising like androgenetic alopecia. Psoriasis, tinea capitis, and contact dermatitis can mimic it — that is why stubborn cases belong in clinic, not endless new shampoos.
Treatment is usually anti-yeast and anti-inflammatory scalp care: ketoconazole, zinc pyrithione, selenium sulfide, sometimes tar, and short courses of medicated foams when a dermatologist directs them. Rotate if one agent plateaus. Hair-loss drugs do not replace this if the diagnosis is seb derm. Minoxidil liquid can sting an already inflamed scalp; foam or treating the dermatitis first is often more tolerable. Pregnancy: ask before using prescription-strength antifungals or steroids on large areas. This is not medical advice. See a doctor for thick plaques, hair coming out in clumps with pain, or scale that bleeds.
Try the free self-check →Sources: AGA review (CCID) ↗
FAQ
Can dandruff cause permanent hair loss?
Ordinary dandruff does not scar follicles the way lichen planopilaris does. Chronic inflammation and scratching can still increase breakage and make density look worse until the scalp is treated.
Is seborrheic dermatitis the same as dry scalp?
Often no. Seborrheic scale is typically oily. True dry scalp may need gentler cleansing and moisture, while seb derm usually needs antifungal or medicated treatment. Guessing wrong can waste months.
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⚠️ When to see a doctor — don’t self-treat
- Sudden patchy or circular bald spots
- Redness, scaling, pus, pain or itch (possible scarring alopecia — treat urgently)
- Broken hairs or rapid loss
- Loss with body-wide signs (weight loss, fatigue, cycle changes, acne, extra hair)
- Loss right after a new medication
- Any hair loss in a child