Dandruff or Dry Scalp: Telling Them Apart

How to tell them apart

Dry scalp produces small, white, dry flakes, and the skin feels tight. It usually comes with dry skin elsewhere, gets worse in winter, and improves with moisture. Dandruff produces larger flakes that are often yellowish and slightly oily, and they cling rather than falling freely. The scalp may look red or feel inflamed, and it is frequently itchier. Dandruff is not caused by dryness and does not respond to oil.

What dandruff actually is

It is associated with a yeast that lives on everyone's skin and feeds on the oils there. In some people it triggers an inflammatory response, faster skin cell turnover, and the flaking that results. Because it involves oil rather than dryness, adding heavy oils to the scalp gives it more of what it thrives on, which is why oiling a dandruff-prone scalp often makes the flaking worse within a week or two.

Treating dandruff

Medicated shampoos are the standard approach, and the active ingredients to look for on the label are zinc pyrithione, selenium sulfide, ketoconazole, salicylic acid or coal tar. Use as directed, leave it on the scalp for the few minutes the bottle specifies rather than rinsing immediately, and expect it to take a few weeks. Alternating between two different actives helps some people when one stops working as well.

Treating dry scalp

Wash less aggressively, use a gentler shampoo, and add moisture rather than oil alone: a water-based scalp spray or a light leave-in on the scalp, then a light oil to seal. A humidifier helps considerably through a Michigan winter, when indoor heating is running for months. If flaking only appears in the cold months and the scalp feels tight rather than itchy, this is almost certainly what you have.

When to see a doctor

Flaking that does not improve after several weeks of a medicated shampoo. A scalp that is painful, weeping, crusting, or has sores or bald patches. Flaking that extends to the face, eyebrows or chest, which can indicate seborrheic dermatitis. Thick silvery scale, which can indicate psoriasis. These are medical conditions with medical treatments, and a dermatologist will resolve in one visit what a shelf of products will not.