Ask a Beauty Editor: Why Is My Scalp So Itchy?

Reader question: Why is my scalp always so itchy? I wash it often! —Lynette Miller
One of the biggest misconceptions about having an itchy scalp is that your hair is dirty and you're not washing it often enough. Although bad hygiene is a potential trigger, it's not always the case. And don't immediately jump to the conclusion of head lice, either—which is the least likely. Since scalp is skin, we've rounded up some dermatologists and hairstylists to help get to the root of the problem.

​Here are some reasons your scalp may be acting up—and what you can do to treat it.

Itchy Scalp Causes

Washing your hair too often (or not enough)
The first reason is probably the opposite of what you're expecting, but washing your hair too often strips your hair of its natural oils, causing dry scalp issues. Dry scalp = itchy scalp (see next reason).
Similarly, not washing your hair often enough can cause excessive oil, dead skin cells, sweat, and hair care products to build up over time and irritate your scalp.

Solution: Unfortunately, there is no magic number for how often to wash your hair. Everyone's hair is unique, so you're going to need to try out a few different options and go with what suits your hair type best. Generally speaking, hairstylists recommend curly and coily hair wash around once a week, while straight and wavy hair should go every two to three days.

Dry scalp
In addition to excessive washing, a dry scalp can be triggered by a lot of things, including the environment, poor nutrition, and simple genetics. The irritation will produce the same symptoms as your classic dandruff (i.e., itching and flaking), but it's important to note that a dry scalp is caused by the scalp's inability to produce enough sebum and natural oils.

Solution: If your scalp's moisture levels are out of whack, vitamin E can help balance and restore natural oil levels due to its antioxidant properties. Try it in a weekly scalp mask and/or conditioning treatment (like a hot oil hair application).

Wrong hair products
If you're a product junkie, you may want to ease up on the hairspray—too many styling products can clog up and irritate your scalp. "It's possible to be sensitized to an ingredient in a hair care product; for example, using a shampoo with fragrance or certain ingredients can irritate the scalp. Essential oils are another common cause of allergic contact dermatitis," says Hadley King, MD, board-certified dermatologist in New York City.

Solution: Keep products like waxes, creams, and oils away from your roots—these can make your hair greasier since they're made with emollients, and irritate your scalp. Check your shampoos, hair masks, treatments, and hairsprays for potentially irritating ingredients—if you're unsure, it's best to rule them out one by one. Additionally, give your locks a detox with a clarifying shampoo once a week.

Dirty pillowcase
Just like contaminated makeup brushes can make you break out, using dirty pillows can affect your scalp. "I'm a big advocate for changing pillows weekly—pillowcases can store hair's natural oils, contributing to it looking greasy," says Davide Marinelli, hairstylist, Cricket ambassador, and founder of Davide Hair Studio in New York City.

Solution: This one is a simple fix—just toss your case in the wash to avoid oil buildup.

Psoriasis
If you have a family history of psoriasis, or you have it elsewhere in your body, it's likely you will develop a spot on your head, too. With psoriasis, your immune system gets angry at your skin, causing raised, reddish, and often scaly plaques, according to Joshua Zeichner, MD, board-certified dermatologist in New York City.

Solution: See a dermatologist to diagnose scalp psoriasis. They may recommend specific treatments , including medicated shampoos, topical steroids (like cortisone), and/or oral steroids. 

Dandruff
Seborrheic dermatitis (aka dandruff) is an inflammatory condition of the scalp associated with an overgrowth of harmless yeast. "A yeast found on the skin called Malassezia contributes to the inflammatory response in seborrhea," says Dr. King. "The skin of the scalp becomes red, dry, and flaky, and symptoms often come and go."

Solution: The goal with seborrheic dermatitis is targeting the yeast and therefore decreasing the inflammatory response. According to Dr. King, you should look for ingredients that are antifungal and antimicrobial, including selenium sulfide, pyrithione zinc, ketoconazole, coal tar, and tea tree oil. The good news is that these ingredients are all commonly found in a slew of OTC hair treatments, shampoos, conditioners, and masks.

Head lice
Although this is the least likely, it's also the most obvious. These tiny, highly contagious bugs live on the head and cause significant itching. They also feed on human blood and lay their eggs at the base of the hair shaft, meaning they will multiply if not tended to. These eggs are often visible upon close inspection of the scalp.

Solution: If you do find lice, everyone in your household will need to be treated with a medicated treatment formulated to kill the bugs—make sure to follow the instructions to the T. You'll also need to wash all bedding, towels, and clothing used by infected family members in hot water and dry on high heat, and soak combs and brushes in very hot water for at least 10 minutes.

Itchy Scalp Treatment
In addition to the solutions listed above, over-the-counter (OTC) products can help manage itchy scalp symptoms. The two active ingredients that you should look for in OTC products are salicylic acid and tar (either coal or wood). They work to slow skin cell growth and reduce inflammation, itching, and scaling.

You can also try an apple cider vinegar (ACV) rinse. Not only does it have anti-inflammatory, antifungal, and antibacterial properties, you can use apple cider vinegar (diluted with water) as a clarifying rinse to get rid of excess product buildup. The high acidity in ACV also works to keep dandruff-causing bacteria and fungus at bay.

Keep an eye on your diet as well. If your scalp (and rest of the skin) feels tight and dry, it may be time to up the intake of omega-3 fatty acid rich foods (fatty fish, soybeans, etc.) and water-heavy foods (cucumber, lettuce, etc). The moisture will make its way through your system and to your scalp. If your itchy scalp isn't improving after a few weeks, consult a trichologist or dermatologist who can further examine your scalp for underlying conditions and devise a treatment plan best suited for you.