(LifeWire) - If you notice thick, itchy red patches on your scalp, you might have scalp psoriasis, a condition that won't affect your general health but can be an uncomfortable and unsightly burden.
You may have a relatively mild case, with just a few red patches scattered randomly across your scalp, each covered with light silvery-gray scales. Or you may have a more severe case with most or all of your scalp being covered with fierce, red patches topped with a thick, crusty scale. Some patches may even extend down onto your forehead, neck or ears.
If you have a more severe case, you may experience some hair loss, although the hair almost always grows back. You may also find that scalp psoriasis can be quite uncomfortable, especially when a tight, crusty scale cap involves your whole scalp. The patches may also be itchy and/or tender.
Like other forms of psoriasis, scalp psoriasis occurs when your body's immune system mis-identifies the skin as being foreign. Under normal circumstances the body makes white blood cells, called T-cells, which should only attack invaders such as viruses, bacteria or fungi. When you have scalp psoriasis, these T-cells accidentally attack your scalp. This causes the scalp to become inflamed, and a cascade of other immune system events result in scalp damage. In the meantime, the scalp tries to repair itself by producing scores of new skin cells; this occurs too vigorously, which results in an overproduction of these new skin cells piling up on each other in heaps. These islands of new skin cells are the thick plaques of psoriasis.
You may only have psoriasis on your scalp, or you may have psoriasis elsewhere on your body. Among the people who have psoriasis, about 50% will have scalp patches. Psoriasis of all kinds tends to run in families.
Psoriasis versus Dandruff
Scalp psoriasis is easiest to diagnose when you already have psoriasis elsewhere. If you only have scalp symptoms, it can be confused with other conditions, such as seborrheic dermatitis. Seborrhea on the scalp usually appears less thick and crusty than scalp psoriasis. The flakes of seborrhea are usually yellow or white, whereas those of psoriasis are a silvery-gray. And plain-vanilla dandruff produces dry, powdery white flakes of scalp skin.
Scalp psoriasis can be particularly difficult to treat because it's hard to apply medications through the hair and onto the plaques that are on the actual scalp, and because of the way the scaly crust adheres doggedly to the hair.
The first step in treating scalp psoriasis is usually to remove as many of the scales as possible. You can accomplish this by washing your hair with special shampoos that contain tar and salicylic acid -- these are available over the counter (OTC) or by prescription for stronger preparations. Using a comb gently while shampooing can help loosen the scale, but don't dig at or pick at the crust, because If you do this you'll be increasing your chances for hair loss and also possibly cause the plaques to bleed. Traumatizing psoriasis can also cause it to spread.
If you have light-colored or gray hair, you should be aware that tar shampoos can stain your hair, with tar gels being less likely to have this effect. In addition, there is some controversy concerning the use of tar and the possibility that it could increase the risk of cancer. Currently, FDA recommendations state that preparations containing between 0.5 to 5% coal tar are safe to use. Tar can also increase your sensitivity to the sun, so follow sun protection guidelines, including sunscreen use, avoiding sun exposure and wearing clothing, hats, etc. for sun protection).If the scale is very thick and hard to remove, then special solutions such as Baker's P & S liquid (a mixture of phenol and sodium chloride, among other ingredients) or liquor carbonis detergens (LCD) therapy (a 10% extract of crude oil tar) can be mixed with oil, massaged into your hair and scalp, and left in place for 6 to 8 hours or overnight. You may want to wear a shower cap while sleeping to protect your clothes and pillows from becoming stained by these solutions. In the morning, shampoo the mixture out of your hair with either shampoo or liquid dish soap. Again, try using a comb gently to loosen and remove the scales while shampooing.
Once you notice that the amount of scale is decreasing, you can use a variety of preparations to treat the actual psoriasis plaques. Steroid creams, gels and foams can be very effective. Some steroid preparations are available OTC, although you'll need a prescription for stronger steroids. To prevent your scalp from becoming thin and fragile, don't use topical steroids for more than 2 weeks at a time unless your doctor advises you to continue treatment for longer. Also, don't ever suddenly stop using topical steroids, as this can result in a sudden flare of psoriasis. Instead, gradually discontinue their use.
In more severe cases, your doctor might recommend steroid injections directly into some of the psoriasis plaques; these are called intralesional steroid injections. A drug called anthralin may also be applied to your scalp. Although this drug is most effective when used in conjunction with exposure of the plaques to UVB light, this is not always possible to achieve in scalp psoriasis, particularly in people with long or thick hair.
Biologics, which are made from human or animal proteins, are another possible treatment. These medications, which include Amevive (alefacept), Enbrel (etanercept), Humira (adalimumab), and Remicade (infliximab), act by blocking certain immune cells that trigger psoriasis.
Very severe cases of scalp psoriasis may require systemic medications that dampen the immune system's over-eager responses, such as methotrexate, cyclosporine, or acitretin. Most of these medications have potential side effects that discourage their use in all but the most severe cases of scalp psoriasis, or when scalp psoriasis occurs along with serious psoriasis elsewhere on the body.
Sometimes the psoriasis plaques become infected with fungi, in which case your doctor might prescribe antifungal creams or oral pills (ketoconazole). These are usually only given for short periods of time due to the potential toxicity of these drugs.
It can take about 8 weeks to get scalp psoriasis under control. Once this happens, you can use a tar shampoo once or twice a week to continue to try keeping the condition at bay. Daily hair washing with any mild shampoo is also a good way to buff the scalp.
As for cosmetics, there seems to be no medical reason to stop dying your hair or getting permanents. Some people feel self-conscious about the appearance of their scalp. A good hairstylist might be able to suggest a style that can disguise the psoriasis and make it easier to treat the scalp. In the meantime, scarves and hats help protect you from sunburn.
Habif T.P."Psoriasis and Other Papulosquamous Diseases." Clinical Dermatology. Fourth ed. St. Louis: Mosby, 2004. 209-239.
Papp, K., et al. "Scalp Psoriasis: A Review of Current Topical Treatment Options." Journal of the European Academy of Dermatology 21. 9 (1 October 2007): 1151-60.
"Scalp Psoriasis." Psoriasis.org. 29 Nov. 2005. National Psoriasis Foundation. 30 May 2008.
"Understanding Scalp Psoriasis May Head Off Hair Loss." PsoriasisNet. 8 Aug. 2007. American Academy of Dermatology. 31 May 2008.