Dandruff and seborrhoeic dermatitis are one condition at two volumes: an inflammatory response to Malassezia yeast on an oily scalp — flaking at the mild end, red greasy-scaled patches at the louder end. It is chronic, it flares with stress and climate, and it matters to your hair: a persistently inflamed scalp is a worse place to grow it, and the itching-scratching-shedding loop does real mechanical damage.
WhatsApp Dr Sin Yong →The reviews describe a three-part mechanism: abundant sebum, Malassezia yeast feeding on it and releasing irritant fatty-acid by-products, and — the deciding factor — an individual inflammatory response to those by-products [1,2]. Everyone hosts the yeast; only responders flake. That framing explains the condition's behaviour: it lives where oil glands crowd (scalp, brows, nose creases, beard, chest), it flares with stress, fatigue and Singapore's heat, and it relapses after every 'cure' because the yeast and the sebum are permanent residents. Malassezia enthusiasts may recognise the organism — it is the same yeast behind fungal acne, running a different scam at a different address.
Three flaky scalps, three plans. Seborrhoeic flaking is greasy — yellowish scale on an oily, often itchy scalp, worse in the oily zones. A genuinely dry scalp sheds fine white powder without redness and drinks moisture gratefully — and is rarer than the shampoo aisle implies. Psoriasis builds thick, silvery, sharply bordered plaques that often extend past the hairline and deserve their own medical pathway. And flaking with broken hairs or patchy loss needs the full differential — the shedding and areata guides cover the neighbours. Scale plus scarring or pustules is specialist territory, promptly.
Evidence-based care is antifungal-first: ketoconazole-class and related medicated shampoos, used correctly — lathered, left to work, and continued at maintenance frequency after clearing, because discontinuation is the classic relapse trigger [1,2]. Flares earn short courses of anti-inflammatory scalp treatment under supervision; routine harshness earns nothing. The hair dividend is real: chronic scalp inflammation associates with increased shedding, and calming the scalp removes both that pressure and the scratching that snaps hairs mechanically. In patients on the hair loss programmes, scalp control is sequenced first — treatments for pattern loss work better delivered onto a quiet scalp, and the H2LT and Regenera pathways assume one.
Scratching the scale off — mechanical damage plus flare fuel. Oiling an oily condition — feeding Malassezia its favourite meal; coconut-oil scalp masks are this condition's accelerant, not its remedy. Antibacterial soaps — wrong kingdom again. Shampoo-hopping weekly — antifungal actives need consistent use to hold the yeast down. And quitting the medicated shampoo the week the flakes vanish — maintenance is the treatment; stopping is the relapse plan.
“Everyone hosts the yeast; only some scalps argue with it — seborrhoeic dermatitis is the argument, and maintenance is the truce.”
— Dr Sin Yong
No — it is an inflammatory response to a yeast on an oily scalp. Overwashing with harsh products can worsen it; the fix is the right active, not more scrubbing.
Chronic scalp inflammation associates with increased shedding, and scratching breaks hair mechanically. Controlling the dermatitis removes both pressures — though zonal pattern thinning has its own cause and its own plan.
Because the yeast and the sebum never left — seborrhoeic dermatitis is managed, not cured, and maintenance-frequency use of the antifungal is the evidence-based truce.
Yes — those are classic seborrhoeic sites, treated with the same antifungal-first logic in face-appropriate formats.
Flares track stress, fatigue and illness reliably — stress modulates the inflammatory response. Managing it helps; it does not replace antifungal treatment.
Thick silvery plaques crossing the hairline (psoriasis), scale with scarring or pustules, or flaking with patchy hair loss — each earns proper medical diagnosis rather than a shampoo experiment.