By Kim Painter, AARP, Apri 2024
An itchy noggin can be miserable, but most causes are treatable. “I can’t concentrate. I can’t sleep. This is driving me crazy. It’s ruining my life.
Those are the kinds of things that dermatologist Brian Kim, M.D., says he hears from patients with persistent scalp itch. It may seem surprising, since our scalps make up a mere 2 percent or so of our skin area, says Kim, who researches chronic itch at the Icahn School of Medicine at Mount Sinai in New York.
But he and other skin doctors say our scalps are a nerve-rich area, prone to itch from many causes. Scalp itch can be “miserable,” but it’s usually treatable, once you figure out what’s going on, says Melissa Piliang, M.D., chairman of the department of dermatology at Cleveland Clinic.
Here are some of the possibilities:
1. Seborrheic dermatitis
This is the condition that causes dandruff, a flaky scalp. In more severe forms, it can also cause very itchy, greasy, scaly patches on your scalp. It’s the most common cause of an itchy scalp with a rash, Kim says.
The underlying cause is a yeast that grows on everyone’s head, Piliang says. You get symptoms when the yeast overgrows. That can happen even if you’ve never had dandruff before, she says, especially if you start washing your hair less often — something that’s common in older adults.
For reasons that aren’t well understood, people with certain neurological conditions, such as Parkinson’s disease and stroke, are especially prone to seborrheic dermatitis, Piliang says.
What to do about it: Start with an over-the-counter dandruff shampoo. These shampoos contain a variety of ingredients. So, if one formula doesn’t work for you, the American Academy of Dermatology suggests alternating between shampoos with different ingredients. Also, try washing your hair more often, Piliang suggests: “If maybe you’re doing it once a week, maybe you try two or three times a week.” If none of that works, see a dermatologist, who can offer prescription shampoos and medications, she says.
2. Psoriasis
If your itchy scalp comes with a scaly rash, another possible cause is psoriasis, believed to be an autoimmune disorder that runs in families and can cause thick, itchy skin patches. Psoriasis can develop at any age, but for late-onset psoriasis, there’s a peak between ages 50 and 60, according to the dermatology academy.
A dermatologist can usually differentiate between psoriasis and seborrheic dermatitis on your scalp because psoriasis patches have clearer, well-defined borders, says Gil Yosipovitch, M.D., a professor of dermatology at the University of Miami Miller School of Medicine. You might also find patches elsewhere on your body.
What to do about it: While there are some over-the-counter shampoos for psoriasis, it’s important to see a dermatologist to confirm the condition and make sure you get the best treatment, Piliang says. She notes that psoriasis can cause complications, such as arthritis, that need treatment as well.
3. Hair dye or other hair products
Even if you’ve used hair color for years, you can develop an allergy to it, especially if it contains an ingredient called paraphenylenediamine, or PPDA, commonly found in permanent hair dyes, Piliang says. Unless you use “wash and wear” dyes that come out after a few washes, it probably contains PPDA, she says.
Scalp reactions to hair dyes tend to be dramatic, Kim says, causing a “rip-roaring … almost poison-ivy type rash.”
Other hair products, including shampoo ingredients, sometimes cause allergic reactions or irritation, Piliang says. If there’s any doubt about the cause, a dermatologist can test your sensitivity to common culprits.
What to do about it: Once you know the cause, the cure is to stop using the product. That can be tough, Piliang concedes. A colleague with a hair dye allergy, she says, was unwilling to give up her dark hair — so now goes twice a week to her hairdresser for wash-and-wear coloring.
4. Pinched nerves
Osteoarthritis and other conditions can lead to spinal stenosis: a narrowing of the spinal canal that can compress, pinch or irritate nerves branching out from the spinal cord. When that happens in your neck area, the nerves that reach your scalp can be affected, resulting in an itch, Piliang says.
What to do about it: There’s no evidence spinal surgery will help the itch, Yosipovitch says. Piliang agrees and says, “many of my patients get better with just physical therapy.”
5. Diabetes
Just as diabetes can cause trouble with the nerves in your feet and hands, it can affect the nerves in your scalp, leading to itchiness, Yosipovitch says. Dry skin and poor blood circulation also can contribute to skin itchiness in people with diabetes, according to the American Diabetes Association.
What to do about it: Medications used for nerve pain, such as gabapentin and pregabalin, may help with this type of itch, Yosipovitch says. However, he says, these drugs can have side effects such as drowsiness, so need to be used carefully in older adults.
6. Shingles
Shingles, a nerve infection that causes a painful, itchy rash, can affect your scalp — not just during the initial rash, which can last weeks, but in the aftermath, which can last years. While the best-known symptom is pain in the areas where the rash occurred, “interestingly on the scalp, some of it is actually itch rather than pain,” Yosipovitch says. When he sees someone with unexplained scalp itching and no rash, he says, he always asks if they’ve had shingles on their head.
What to do about it: Some people take medications for nerve pain during their initial outbreak, and that may help prevent longer-term pain and itching, Yosipovitch says. Those medications also can be tried if the itch returns, he says. Anti-itch shampoos and steroid creams won’t work, he says.
7. Other nerve problems
Many older adults who have red, itchy scalps but no true rash and no obvious condition explaining their symptoms likely have some form of nerve deterioration, Kim says. The decreasing ability to interpret sensations as we age may make us more prone to itching, including on the scalp, he says. “As you age, you actually lose the ability to suppress itch,” he says.
What to do about it: If a full medical investigation turns up no obvious cause, you might try drugs for nerve pain, like gabapentin, Kim says. He says he gives some patients an opioid drug called butorphanol.
8. Anxiety and other mental health problems
Conditions such as anxiety, depression and obsessive-compulsive disorder can lead some people to scratch their heads, creating irritation, which leads to more itching and scratching, Yosipovitch says.
What to do about it: Treatment of the underlying condition, with medications, cognitive behavioral therapy, or other mental health interventions, is the best approach, he says.
9. Autoimmune conditions
A rare disorder called dermatomyositis, which causes muscle weakness and rashes, sometimes starts with an itchy scalp, Piliang says. Other autoimmune diseases, such as lupus, can also cause scalp itching, she says.
What to do about it: Make sure you tell your doctors about all your symptoms, so you can get the right diagnosis and treatment.
10. Hair loss conditions
Some types of hair loss that occur mostly in women can cause scalp itching, Piliang says. One, lichen planopilaris, causes scarring and patchy hair loss, along with itching and burning, often in postmenopausal women. Another, central centrifugal cicatricial alopecia, most often happens in Black women and starts with hair loss in the center of the head.
What to do about it: These conditions are treated with anti-inflammatory drugs and other medications.
11. Infestations
It’s rare for an older adult’s itchy scalp to be caused by lice, which mostly afflict children, Piliang says. Those in group settings like nursing homes do sometimes get scabies, an itchy ailment caused by mites, but skin folds are more common trouble spots, she says. Scalp infestations can happen, though, she says.
What to do about it: Use prescription creams or pills that kill the mites.
12. Skin cancer
Your itchy scalp probably isn’t cancer and the most serious form of skin cancer, melanoma, usually doesn’t itch, Yosipovitch says. But basal cell and squamous cell skin cancers can get itchy and irritated and can develop on your scalp, he says.
What to do about it: If you find an itchy or irritated spot on your head, get it checked by a dermatologist.
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