This is why your scalp is so damn itchy

Got an itch on your head that you just can't scratch? If those prickles and tingles go way beyond what feels normal, you might be wondering what's to blame.

Is it an allergy? An infection? Something even more serious? We rounded up some common (and uncommon) causes of scalp itch, along with information on what you can do to stop scratching for good.

THE USUAL SUSPECTS

Flaky, itchy dandruff, bane of half the population, has three main causes: an oily scalp (not a dry one), a buildup of dead skin or styling products, or a yeast-like fungus called malassezia. Vigorously massaging shampoo into your scalp (not just into your hair) may lift product buildup, but if flaking persists, use shampoo containing zinc or salicylic acid, which treat fungus, buildup, and oil; try Head & Shoulders Classic Clean Shampoo ($6, amazon.com). Still itching after a few weeks? You may need to visit your derm to see if something else is going on.

HIDDEN CULPRITS

Ingredients in some hair products can prompt an allergic reaction, says Maria Hordinsky, M.D., professor and chair of dermatology at the University of Minnesota in Minneapolis. "The allergen is often fragrance, or a moisturizing agent called propylene glycol." If your whole head feels itchy, stop using these suspects for a week; if the irritation goes away, replace your old products with fragrance- or PG-free options (for the latter, try the Alba Botanica line, available at drugstores and at Target.com). Scorching temps from styling tools like blow-dryers, flatirons, and curling irons can also dry out the scalp and cause itchiness, so keep heat settings on medium.

Learn how to blow dry fine hair to make it look full and gorgeous: ​

When your itch is in just one spot, it could be a skin condition like psoriasis, an autoimmune disease that causes raised, scaly patches, says dermatologist Joshua Zeichner, M.D., director of cosmetic and clinical research at Mount Sinai Hospital in New York City. If your dermatologist determines this is the case, use a shampoo with coal tar—sounds weird, but it works—like Neutrogena T/Gel Therapeutic Shampoo ($5, amazon.com). Your doc can prescribe stronger remedies if needed.

Looking for a new all-body moisturizer? Try this organic coconut oil, from the Women's Health boutique.

One itch that's rare but not to be ignored: A crusty spot about a quarter-inch in diameter could be a precancerous lesion called actinic keratosis, the result of sun exposure over many years, says Hordinsky. About 10 percent of these become cancerous, so see your derm ASAP to have it checked and, if needed, removed. Ward off future damage by using a sunscreen specially formulated for the scalp, such as Banana Boat Sport Quik Dri Scalp Spray ($9.99, jet.com)—yes, in the winter too.

This article originally appeared in the January/February 2018 issue of Women's Health. For more great advice, pick up a copy of the issue on newsstands now!