When an intense itchiness strikes your scalp, it can be hard to concentrate on anything else.
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And while most cases of a scratchy scalp are totally temporary or treatable, some are a sign of a more serious health condition.
Here, Y. Claire Chang, MD, a board-certified dermatologist at Union Square Laser Dermatology, discusses the top 10 reasons why the top of your head might be held hostage by an insistent itch, plus what you can do to soothe your scalp when it's irritated.
If over-the-counter treatments are not working to relieve an itchy scalp, or you develop pain, inflammation, fever or chills, seek medical care immediately to determine and treat the underlying cause, Dr. Chang says.
1. You Have Dandruff
If your itchy scalp is accompanied by snowy white flecks flaking onto your shoulders, you're probably dealing with dandruff.
"Dandruff, also known medically as seborrheic dermatitis, is a common condition that affects up to half the adult population and involves an itchy, flaky and scaly scalp," Dr. Chang says.
Dandruff falls on a spectrum of inflammatory skin diseases that affect seborrheic — or oil-producing — areas of the body (including the scalp, central face and upper chest), Dr. Chang explains. And though its cause is not completely clear, there's an association with yeast living on the skin, she says.
The condition can also worsen in winter months or with stress, Dr. Chang adds.
Fix it: “For mild dandruff, most people will improve with over-the-counter products and shampoos,” Dr. Chang says.
A variety of active ingredients can decrease dandruff. Here are some of the things to look for in a dandruff shampoo, per Dr. Chang:
- Selenium sulfide: “Selenium sulfide can be used to relieve itching and flaking of the scalp by reducing excess scalp fungus and reducing the rate of shedding of dead skin cells on the skin surface,” Dr. Chang says.
- To maintain control of dandruff, lather up with a selenium sulfide shampoo (like Selsun Blue Antidandruff Shampoo or Head & Shoulders Clinical Strength Dandruff Defense Shampoo) two to three times per week and let it sit on your scalp for up to three minutes.
- Salicylic acid: Shampoos that contain salicylic acid (like Neutrogena T/Sal Shampoo) can help eliminate excess scale, Dr. Chang says.
- Ketoconazole: Anti-fungal shampoos that contain ketoconazole (like Nizoral Anti-Dandruff Shampoo) are effective in killing dandruff-causing fungi on the scalp, Dr. Chang says.
- Pyrithione zinc: Shampoos with pyrithione zinc (like Head & Shoulders Classic Clean) help kill yeast and decrease scales.
- Coal tar: Products with coal tar (like Neutrogena T/Gel Therapeutic Shampoo and MG217 Medicated Coal Tar Shampoo) help the outer layer of skin shed and minimize flaking.
“If the itch is severe, you can see your board-certified dermatologist for a prescription steroid shampoo,” Dr. Chang says. “[However] steroid formulations should be used with caution and sparingly, as chronic use can thin the skin,” she adds.
2. It's an Allergic Reaction
An itchy scalp can indicate an allergic reaction to something like a hair product.
"Allergic contact dermatitis can affect any part of the skin, including the scalp," Dr. Chang says.
Any number of hair products, including shampoos, conditioners, hair oils or hair dyes, that contact the scalp can result in redness, itching or burning, she says.
Fix it: “To treat allergic reactions, the most important step is to stop using the culprit product,” Dr. Chang says. “Repeated contact will cause recurrent reactions."
The problem is, “many times patients do not know exactly what product or ingredient they are reacting to,” Dr. Chang adds. “In this case, patients can consult their local allergist or dermatologist for specific allergen testing (also called patch testing)."
In the meantime, your doctor can also treat an active rash by prescribing topical steroids, which can help relieve the itch and inflammation, Dr. Chang says.
3. You've Got Hives
If your scalp is covered in red, itchy welts, you may have hives.
"Hives, also known as urticaria, are pale red and white swollen bumps that appear suddenly on the skin and can be caused by allergic reactions to a wide variety of triggers, including foods, medications, stings, pressure, heat and even stress," Dr. Chang says.
Fix it: “Hives themselves do not necessarily need treatment because they usually self-resolve [typically lasting no more than 24 hours],” Dr. Chang says. In the interim, you can use anti-itch creams and oral antihistamines to soothe your symptoms, she says.
But to avoid future flares, knowing what triggered your hives in the first place is key, Dr. Chang says. Once again, it might be a smart idea to see your doctor, who can test you for a variety of allergens.
If your hives are accompanied by problems swallowing, swelling of the eyes, throat or mouth, a racing heart or lightheadedness, seek immediate medical attention as this may be a sign of a serious, potentially life-threatening allergic reaction, Dr. Chang says.
4. You Have Lice
Creepy crawlies like lice (also known as Pediculus humanus capitis) could be the culprit behind your itchy scalp.
Usually spread by direct contact with another infected person, head lice are insects that feed on human blood and live on the human scalp, Dr. Chang says. And while these nasty little bugs are more common in children (you might remember getting checked for lice in elementary school), they don't discriminate against adults.
The most common symptom of head lice is, you guessed it, itching on the scalp (as well as the neck and ears).
"The itching is actually an allergic reaction to the insect bites," Dr. Chang says. "Patients can also get sores on the head caused by scratching," she adds.
Fix it: “Head lice is usually diagnosed clinically by your health care provider, who will use a fine-toothed nit comb through the hair to identify a live nymph or adult louse,” Dr. Chang says.
“Treatment involves application of lice medicine, like Permethrin or Ivermectin, to all affected individuals in the household,” she says.
You might also need an additional treatment seven to 10 days later to kill any newly hatched lice.
5. It's Scabies
Unfortunately, lice aren't the only perturbing pests that can sabotage your scalp health. Other teeny, insect-like parasites can produce a skin condition called scabies, which might be the source of your itchy scalp.
Often spread by direct skin-to-skin contact, "scabies is an infection by human mites (Sarcoptes scabiei var hominis) that burrow into the upper layer of the skin and lays eggs," Dr. Chang says.
In addition to intense itching and a red, bumpy rash, you might also notice tiny, raised linear burrows in the skin, Dr. Chang says.
While scabies can occur on the scalp in infants and young children, in adults, it is more common in sites like the wrists, elbows, finger webs, armpits and private areas (except for immunocompromised and severe cases), she explains.
Fix it: “Scabies is diagnosed clinically by appearance of the rash and by skin scrapings showing the mite, mite eggs or mite fecal matter,” Dr. Chang says.
In most cases, the infection is treated with scabicides that kill the scabies mites.
“Usually, permethrin cream is prescribed for the patient as well as all household contacts,” Dr. Chang says. The cream is applied to the whole body and left on for eight to 14 hours.
“Oral ivermectin is sometimes used in patients who are immunocompromised or for a variant called crusted scabies,” Dr. Chang adds.
6. You Have Ringworm
Ringworm could be the root of your ridiculously itchy scalp.
Most common in toddlers and children, "ringworm of the scalp, also called tinea capitis, is a rash caused by a fungal infection that can create itchy, scaly or red patches on the head," Dr. Chang says.
In addition to an irritated, itchy scalp, ringworm can also wreak havoc on your hair.
"The hairs in the affected areas are often brittle and fragile, leaving small black dots (where the hairs have broken off)," Dr. Chang says.
Fix it: “Prescription oral anti-fungal medications are the treatment of choice for tinea capitis,” Dr. Chang says.
7. You've Got Psoriasis
Your scalp is made of skin, which means it's susceptible to issues like psoriasis.
"Scalp psoriasis is a common inflammatory skin condition that causes well-defined, red, thick, scaly patches on the scalp," which can be associated with itching or burning, Dr. Chang says.
- While this inflammatory skin disease has similar symptoms to dandruff, the type of scaliness seen in psoriasis sets it apart: "In contrast to the light flakes of dandruff, psoriasis tends to be associated with a thicker, silvery-white scale," Dr. Chang says.
Psoriasis can also affect other parts of the body and may be related to a form of arthritis (known as psoriatic arthritis), she adds. This condition can also be associated with changes in the nails, known as nail pitting.
Fix it: Over-the-counter treatment options include shampoos that contain salicylic acid or coal tar, but, depending on the severity of your scalp psoriasis, you may need prescription-strength steroid shampoos to keep the skin condition in check, Dr. Chang says.
8. It's Eczema
Just like psoriasis, eczema, also known as atopic dermatitis, can also affect the scalp, Dr. Chang says. Eczema is a chronic skin condition that causes itching, redness and scaling.
In addition to your scalp, these irritating symptoms may also present themselves on the hands, feet, ankles, wrists, neck, upper chest, eyelids and inside the bend of the elbows and knees, according to the Mayo Clinic.
Fix it: The cycle of frequent wetting and drying can make eczema worse, so “frequent moisturization is the best prevention,” Dr. Chang says. Moisturizing after bathing, within minutes, can help trap moisture in the skin.
And try to avoid triggers that may exacerbate your eczema, including sweat, stress, certain soaps and detergents (especially those with fragrance), dust and pollen, per the Mayo Clinic.
Your doctor may also prescribe a topical steroid to help relieve itching, Dr. Chang says.
9. You Have Nerve Issues
If you have an itchy scalp without any other skin symptoms like a rash, it might be a signal of a nerve issue.
While you probably associate nerve conditions with pain, neuropathies can also cause itching (and burning sensations) along the distribution of nerve branches, Dr. Chang says.
And because the skin of your scalp contains many nerves, it can result in a whole lot of itching.
OK, but why does this happen? Neuropathies can be due to "anomalies in the nerves themselves or infections like shingles that affect the nerves," Dr. Chang says.
Fix it: Consult with your doctor, who can assess you for nerve-related problems and properly treat the underlying cause (which will hopefully curb the itching).
10. It Might Be Skin Cancer
Though less common, skin cancer can cause itching of the scalp too, Dr. Chang says.
In addition to itchiness, skin cancer can present in a plethora of ways, including the following, per the American Academy of Dermatology (AAD):
- A changing mole or a mole that looks different from your others
- A dome-shaped growth
- A scaly patch
- A non-healing sore or sore that heals and returns
- A spot of skin that bleeds
Fix it: If you suspect your itchy scalp is associated with skin cancer, see a board-certified dermatologist who can examine the affected area, diagnose and treat you appropriately.
Is this an emergency? If you are experiencing serious medical symptoms, please see the National Library of Medicine’s list of signs you need emergency medical attention or call 911.