By Debra Jaliman, MD
Dandruff is a minor skin condition, but very annoying to those who have it, and it can sometimes be surprisingly hard to treat.
Exactly what causes dandruff is something of a gray area. It may be the result of a yeast overgrowth on the scalp or seborrheic dermatitis (which also shows up as greasy scales on eyebrows and the sides of the nose). Sometimes flakes are caused by sensitivities to hair products or dyes. If the itch is severe, it can be treated with steroid creams for a week or two to bring it under control. If the scales are very thick or there is a crust on the scalp, it may well be psoriasis, which requires specific prescription drugs.
Over-the-counter shampoos work well in mild cases. The active ingredients are usually zinc pyrithione, selenium sulfide, salicylic acid, ketaconazole or tar. It’s really a matter of trial and error to find which works best for you. I usually recommend starting with zinc pyrithione or salicylic acid shampoos. If they don’t work – or if they stop working after a time – try a shampoo with 1% ketaconozole. The 2% ketaconazole shampoo is more effective, but usually requires a prescription. Even better is prescription ketaconazole foam, which is quite expensive, but gives excellent results; a generic ketaconazole foam, which will probably be considerably less expensive, has just been approved by the Food and Drug Administration. I am less enthusiastic about tar shampoo. Tar is carcinogenic and should not be used for long periods; besides, patients complain that tar shampoos have a funny smell and change the color of grey or blonde hair.
The trick to every dandruff shampoo is leaving it on long enough. Most people don’t realize that in order to work, medicated shampoos have to be left on for at least five full minutes. I always tell my patients to keep a kitchen timer in the bathroom. The other factor is consistency – to treat dandruff successfully, I recommend washing hair every day or every other day. Shampooing just once or twice a week is not going to do much. Dandruff shampoos do tend to be leave hair feeling dry, so make sure to use conditioner.
If your dandruff doesn’t clear up with over-the counter-shampoos, my best advice is to go to a dermatologist to establish what is going on in your scalp. Dandruff can also be caused by vitamin deficiencies (usually vitamin B-6, D or A) or insufficient essential fatty acids in your diet. For reasons not fully understood, dandruff is also associated with Parkinson’s disease, heart attacks, strokes and autoimmune diseases.
Bottom line: Dandruff can be treated, but treatment must be consistent to work.