Flaky scalp and dandruff are a frequent concern for patients, as the condition can result in white scales on dark clothing that can cause some embarrassment. This condition is not one thing, as many dermatologic diseases can lead to dandruff. Dandruff is nothing more than dead skin cells that result from increased cellular turnover. The normal turnover time for skin is about 1 month; for dandruff it can be as little as 2 weeks. Many skin conditions can cause dandruff, most commonly psoriasis, seborrheic dermatitis, and eczema.
Psoriasis commonly affects the scalp and can lead to dandruff. It is an autoimmune condition that leads to inflammation in the skin, which in turn results in increased chemical signals (called cytokines) that speed up cellular turnover. Seborrheic dermatitis results from an inflammatory reaction to a harmless yeast (Pityrosporon ovale) that lives on the skin. This results in redness, irritation and scaling. The dandruff in seborrheic dermatitis tends to have a greasy feel and texture to it, as opposed to psoriasis which is more silver-colored and dry.
Eczema is a general term for inflammation in the skin and has many causes, the most common of which is irritation due to harsh shampoos and hot water. The goal of any dandruff treatment is to reduce the flaking (and itching, if any). In general, treatments are aimed at decreasing inflammation in the skin while at the same time dissolving the dead skin cells (called keratolysis). A good over-the-counter shampoo is Neutrogena T-Sal shampoo, which helps loosen flakes and is great at dissolving the dead skin cells on the scalp.
Make sure you let the shampoo sit on the scalp (not the hair) for 5 minutes or so before you rinse. To combat inflammation and redness of the scalp, an anti-inflammatory shampoo is a good choice. A good option that is available over the counter is Head and Shoulders Active Sport, which contains 1% zinc pyrithione. Zinc pyrithione has been shown to have potent anti-inflammatory and anti-yeast properties. Ketoconazole 1% shampoo, available over the counter, is also a good choice for mild cases.
Ketoconazole 2% shampoo is more effective and is indicated for moderate to severe cases, but is only available with a prescription. Prescription cortisone, when combined with ketoconazole 2% shampoo, is sometimes needed to help control the condition. For eczema related dandruff, use a shampoo that has the least amount of irritating chemicals (such as parabens, lanolins, formaldehyde, and cocomidopropyl betaine) in it. A great choice is Free and Clear shampoo, available on Amazon. It is non-alkaline and can be used daily. All of these shampoos must be used at least three times per week to see any benefit.
Dana Point Dermatology’s Bottom Line: Dandruff is a common problem in patients and is usually a symptom of a skin condition. Your first step is to have a board-certified dermatologist make the specific diagnosis, as the condition can be easily controlled when this is known.
