Itch

Itchy Scalp?

You aren’t alone – flaking and itching are extremely common scalp problems. Almost 5 in 10 people have struggled with an itchy scalp while close to 4 in 10 people have reported problems with scaling and flaking.

There are many causes of an itchy scalp, each with its own treatment. Here we will discuss the most common causes of itchy scalp and the treatment for each.

Why the scalp?

The unique features of the scalp put it at risk for irritation and infection. Brushing and styling hair causes friction that can lead to irritation and inflammation of the scalp. Hair products such as shampoos, conditioners, and coloring dyes can also irritate the scalp.

The scalp is also at risk for fungal and parasite infections. The scalp’s oily secretions and dead skin cells provide food for fungi. The scalp’s hair creates a dark, moist and warm environment that is perfect for parasites.

Common causes of an itchy scalp

The most common causes of an itchy scalp can be broken into three categories:

  • Fungal infections
  • Parasitic infections
  • Inflammatory conditions of the scalp

All of these different scalp conditions can cause the same symptoms of itching, scaling and scalp redness. In order to effectively treat scalp itching, you must first know the cause of the itch.

Fungal infections

Dandruff and Seborrheic Dermatitis

Both dandruff and seborrheic dermatitis are caused by the Malassezia yeast, a fungus that is found naturally on healthy skin.

Dandruff is extremely common – it affects 1 out of every 2 people. Almost 50% of people with dandruff experience small white or grey flakes either in patches of the scalp or throughout the entire scalp. Most people with dandruff (66%) have itching. It is also common to feel as though your scalp is tight, dry or irritated.

Seborrheic dermatitis is a medical term that describes a more severe form of dandruff. Usually the scalp is red and irritated. Instead of flakes, there are large greasy scales that can become crusty. Often, seborrheic dermatitis will also be found around the eyebrows, corners of the nose, and chest. Itch may occur in any of the areas of the scalp or face where seborrheic dermatitis is present.

Treatment: Antifungal shampoos are used to treat dandruff and seborrheic dermatitis. These shampoos contain selenium sulfide, ketoconazole, pyrithione zinc or ciclopirox. Over-the-counter shampoos can be used to treat dandruff. However, people with more severe dandruff or seborrheic dermatitis may need a prescription strength shampoo to treat the itch and flaking associated with their condition. Be sure to check with your doctor.

To ensure success when treating dandruff, be sure to:

  • Follow the shampoo’s instructions. Some shampoos should be left on the scalp for up to 5 minutes. Sing a song in the shower while you let it sit.
  • Use the shampoo 1-2 times per week.
    • If you are African-American, shampoo once a week with an antidandruff shampoo
    • If you are Asian or Caucasian, shampoo twice a week with antidandruff shampoo
  • Try alternating shampoos with different active ingredients if the dandruff does not initially improve. Sometimes the fungi can be resistant if you use the same shampoo.
  • Consult your doctor or dermatologist if itching and flaking persists. There are many other scalp conditions that can mimic dandruff or seborrheic dermatitis.

You can watch a video about dandruff and how to treat it here.

Tinea Capitis

Tinea capitis is ringworm of the scalp. It is caused by a fungus that infects the top layer of skin. The fungi are spread by contact with infected people, infected pets or by sharing objects like brushes and pillows. Children are most likely to get a tinea capitis infection.

In addition to itching of the scalp, tinea capitis can cause pustules (bumps with pus inside) or flaking. The infection can also cause hairs to break and areas of the scalp are left without hair. A doctor can diagnose tinea capitis by scraping the skin and looking at flakes of skin under a microscope for fungal elements.

Treatment: Unlike ringworm of the body that can be treated with topical antifungal medication, tinea capitis must be treated with an oral antifungal medicine. The fungus can be deep inside the hair follicles making creams and shampoos ineffective. Additionally, both the person infected and all family members should be treated with antifungal shampoo. Your pets can be infected and may not have symptoms. Therefore, any pets in the house should be checked for infection by the veterinarian.

Parasitic infections

Head lice (pediculosis capitis)

Head lice are more common in children. They can be passed by contact with someone who has head lice or by sharing objects like brushes or pillows. In addition to itching, the lice can be seen on the scalp, although they are very small (3-4mm). Head lice are diagnosed by seeing the lice or nits (eggs) on the scalp or hair.

Treatment: Shampoos or lotions containing permethrin are commonly used to treat head lice. The treatment should be used once then repeated 7 to 10 days later. Family members should also be checked for infection, as itching may not develop until weeks after being infected.

Scabies

Scabies is an itchy skin condition caused by mites. It is a rare cause of scalp itching in most people because the infection does not typically involve the scalp. However, it may involve the scalp in infants and in people with weak immune systems.

Treatment: Scabies is treated with a topical permethrin cream that is applied over the entire body from the neck down. The cream is worn overnight and washed off in the morning. It’s important that this entire process is repeated again 7 to 10 days later. The cream only kills the mites, not the eggs.

Inflammatory Conditions

Psoriasis

Psoriasis is an autoimmune disease that causes raised red patches of skin (called plaques) that are covered with gray scale. 50% of people with psoriasis have activity on the scalp. In some cases, the scalp may be the only affected area of skin. Plaques can be anywhere on the scalp or along the edge of the hairline. Early on, psoriasis of the scalp can look similar to dandruff.

If other family members have psoriasis, you may be at increased risk for psoriasis. A dermatologist can diagnose psoriasis of the scalp and prescribe the appropriate treatment

Treatment: Although it can be difficult to treat psoriasis in the scalp, there are multiple topical treatments that can help. Your dermatologist may prescribe salicylic acid to break down the scales of psoriasis and topical steroids for inflammation. Tar shampoo, which decreases skin proliferation, is can be used as well. A topical steroid such as clobetasol either as a foam or solution may be used as well.

Allergic Contact Dermatitis

Hair products can cause an allergic contact dermatitis with severe itching. The scalp may be red and scaly, or in severe cases, there can be blisters. Given that allergies can develop at any time, the product causing the contact dermatitis might be something you have used for a long time.

Treatment: The treatment for contact dermatitis is to discontinue use of the offending products. If your dermatologist suspects a contact dermatitis, he or she may recommend patch testing to identify the specific allergen so you can know what products to avoid.

Atopic Dermatitis (Eczema)

Although eczema is a common cause of itchy scalp in infants, it is less common in older kids and adults. In older kids and adults, eczema of the scalp typically occurs with severe eczema. Therefore red, itchy rashes will be present in other areas of the body.

Treatment: The treatment of atopic dermatitis includes decreasing inflammation and repairing the skin’s barrier. Thick creams can be used to help the skin heal. Typically your dermatologist will recommend prescription strength topical steroids to decrease inflammation.

Bottom Line on that Itchy Scalp

The treatment for scalp itch is different depending on the problem that is causing the itch. Dandruff is an extremely common cause of scalp itching and flaking. The treatment of dandruff with antidandruff shampoo is easy and safe.

However, if an over-the-counter anti-dandruff shampoo has not relieved the itching, make an appointment with your doctor to see if there is an underlying skin condition or skin infection that needs treatment.

Sources:

Chosidow O. Clinical practices. Scabies. N Engl J Med 2006; 354:1718.

Dandruff: How to Treat. American Academy of Dermatology. Web. 1 May 2016. <https://www.aad.org/public/diseases/hair-and-scalp-problems/dandruff-how-to-treat>.

Elewski BE. Clinical diagnosis of common scalp disorders. J Investig Dermatol Symp Proc 2005; 10:190.

Moriarty B, Hay R, Morris-Jones R. The diagnosis and management of tinea. BMJ 2012; 345:e4380.