Seborrhoeic dermatitis — the flaky, itchy scalp condition caused by Malassezia yeast overgrowth — is one of the most common causes of scalp inflammation, and there is meaningful evidence that chronic scalp inflammation exacerbates androgenetic hair loss in those who are already predisposed. Treating seborrhoeic dermatitis is therefore not only about scalp comfort but about optimising the scalp environment for hair retention.
The inflammation associated with seborrhoeic dermatitis affects the peri-follicular tissue — the tissue immediately surrounding the follicle. Chronic inflammation at this level can accelerate the miniaturisation process in follicles that are already under androgenetic stress, producing more rapid or more extensive hair loss than would occur in an uninflamed scalp with the same genetic predisposition.
Treatment: ketoconazole shampoo (2% prescription or 1% OTC) is the most effective and best-evidenced first-line treatment. Used two to three times weekly, it reduces Malassezia, controls flaking and inflammation, and has the adjunct benefit of modest anti-androgenic activity at the follicle. Selenium sulphide shampoo is an alternative with similar antifungal action.
For severe seborrhoeic dermatitis that does not respond to antifungal shampoo: a short course of mild topical corticosteroid (clobetasone butyrate 0.05%) to the scalp reduces acute inflammation rapidly. Longer-term use of potent topical corticosteroids on the scalp carries risk of skin thinning and should be managed by a dermatologist or GP.
If you have both androgenetic hair loss and seborrhoeic dermatitis, treating the dermatitis is not a cure for the hair loss — but it removes an inflammatory exacerbating factor and is worth addressing as part of a comprehensive management approach.
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