Psoriasis of the scalp is very common. Nearly 80% of psoriasis patients develop plaques on the scalp, and in the great majority of these cases, scalp disease persists for at least five years. Scalp psoriasis is especially distressing to many patients. The plaques are often itchy, and when they extend beyond the hairline onto the face and around the ears, they are highly visible. In some cases, scalp psoriasis can also cause hair loss. Unsurprisingly, patients are eager for effective treatment.
In theory, psoriasis of the scalp responds to the same topical and UV therapies that work well on other areas of the body; however, applying these treatments to the scalp in a practical way has proved challenging. It is difficult to apply topical medications under the hair, and due to their greasiness or strong odor, some topical preparations are cosmetically unpleasant when used on the scalp. Hair also limits the exposure of the scalp to UV light. Traditional UV therapy is often not possible on the scalp and even natural sunlight won’t do much good if hair is blocking rays. Finally, scalp plaques are often thick and scaly, so topical treatments do not penetrate well.
Topical medications for scalp psoriasis come in several formulations: shampoos, lotions, creams, gels, foams, and ointments. With the exception of shampoos, which can be applied for as little as 15 minutes and then rinsed out, these preparations must be left on the scalp for at least several hours. Most are used once or twice daily for several weeks or months at a time. For overnight applications, patients can cover their scalp with a plastic shower cap to keep the medication from rubbing off during sleep (but check with your physician first, as this has the effect of increasing the dose of medicine reaching your system). Compared to other formulations, ointments may be less desirable from the patient’s point of view because they are difficult to rinse out, especially from long hair.
Topical corticosteroids, both high potency (e.g. clobetasol and betamethasone) and medium/low potency (e.g. hydrocortisone and fluocinolone acetonide), are commonly used to treat scalp psoriasis. Typically the strategy is to use the least powerful steroid that will give the patient adequate results, as stronger steroids naturally bring greater potential for side-effects, including development of spider veins and thinning of the skin. Overuse of topical steroids can also lead to suppression of the body’s own steroid production system (the Hypothalamus-Pituitary-Adrenal [HPA] Axis), which can, among other things, cause a worsening of psoriasis due to flare or rebound. Corticosteroid preparations are normally applied 3-4 times a week and work quickly, producing results in about 3-4 weeks. When ending steroid use, it is typically safest to “wean” off the products, rather than eliminating their use abruptly; but again, check with your physician.
Corticosteroids are available as shampoos, creams, lotions, and foams. They are popular with psoriasis patients because they typically work well, and can be used safely. But they are also sometimes used too long or too extensively (perhaps on the scalp and on the skin simultaneously), and this can lead to the side-effects concerns mentioned above. Popular products include a shampoo containing clobetasol (Clobex Shampoo), and a low potency corticosteroid, fluocinolone acetonide, in an oil preparation (Derma-Smoothe/FS).
Vitamin D3 Analogs
Since their introduction in 1992, Vitamin D3 analogs have proved to be safe and effective treatments for scalp psoriasis. Calcipotriene (Dovonex, with a generic version appearing as soon as 2008), also known as calcipotriol, the most commonly prescribed Vitamin D3 analog, has excellent anti-psoriasis effects, and unlike natural Vitamin D3 and other Vitamin D3 analogs, it does not cause calcium levels in the blood to rise abnormally. Patients have used calcipotriene safely for up to twelve months in clinical studies. The most common side effect is irritation or a burning sensation at the site of application.
Calcipotriene does not work as quickly as corticosteroids do, taking up to 8 weeks to reach maximum effectiveness. However, it is ultimately very effective. In one study, 80% of patients experienced significant improvement or clearing of scalp psoriasis after using calcipotriene lotion for 10 weeks.
Calcipotriene + Corticosteroids: A Powerful Combination
Simultaneous use of calcipotriene and corticosteroids is more effective than either therapy alone, and the combination appears to minimize the side effects of both. The combination works as quickly as the faster acting corticosteroid component, producing good results in about four weeks.
While some physicians prescribe both and have their patients switch back and forth daily or in some other fashion, a product recently won FDA approval that combines both and has been clinically shown to be effective. The product is called Taclonex, and it is marketed by the same company that markets Dovonex.
Coal tar has been used to treat skin diseases for hundreds of years, making it one of the oldest remedies for psoriasis. There are several over-the-counter lotions and shampoos containing coal tar available for the treatment of scalp psoriasis, including popular brands like T-Gel and T/Sal. Although coal tar works well against psoriasis, including in reducing the itch that many psoriasis patients battle, coal tar has a strong, unpleasant odor that cannot completely be masked by the addition of more pleasant-smelling ingredients. What’s more, coal tar has been show to be carcinogenic (cancer-causing) in animals, and in Europe in particular, its potential to be a human carcinogen is of great concern. Unfortunately, we are still awaiting a definitive study that would track a large number of psoriasis patients over a long period of time, with one group using coal tar and the other not. Until then, the question appears unresolved, although a follow-up of a couple hundred coal tar users after 25 years found no larger-than-expected cancer rate. As with most things in psoriasis, each patient must balance known and unknown risks against the benefits of various treatment options. On that basis, coal tar remains a popular choice.
Dithranol is another old remedy for psoriasis, in use for more than 80 years. Dithranol treatment is usually administered at a clinic or in-patient setting. A dithranol cream formulation is applied to the scalp for a short period of time (5-60 minutes) and then washed off. Prolonged exposure to dithranol can irritate the skin and dithranol will also stain clothes and temporarily discolor skin and hair. Despite these drawbacks, some patients who have not responded to other topical medications find that dithranol works well.
Salicylic Acid and Urea
Scalp psoriasis is often highly scaly, which can block the penetration of other medications into the skin, limiting their effectiveness. Therefore, patients with scaly psoriasis may benefit from an initial course of treatment with an agent that reduces scaling, such as salicylic acid ointment. Usually, patients apply the ointment several times over a 2-3 day period and then proceed with treatments that can alleviate their other psoriasis symptoms. Products with urea are also popular to reduce psoriasis scales.
Because of the shielding effect of hair, traditional UVB lamp therapy is not very effective against scalp psoriasis. However, a couple of recent articles have reported success in using the 308 nm excimer laser on the scalp. The laser generates a small spot of UVB light that can be precisely aimed. The hair is parted using a device similar to a blow dryer, and the laser is applied to the exposed patch of scalp.
In one study 35 patients whose scalp psoriasis had previously failed to respond to topical medication were treated with the laser twice a week for an average of 21 treatments. Nearly all of the patients improved by at least 50%; in half of the patients, psoriasis cleared or almost cleared (greater than 95% improvement).
Systemic Treatments and Biologics
Patients who have significant scalp psoriasis that does not respond to topical medications might consider using a systemic medication (methotrexate, cyclosporine, or acitretin [Soriatane]) or one of the biologics (Amevive, Enbrel, Humira, Remicade, Stelara or Simponi). The risks and benefits of these medications for patients with scalp psoriasis are similar to those for patients whose psoriasis involves other areas of the body. But because these treatments are taken internally via pill, injection or infusion, the challenges posed by thick scaling and/or hair do not get in the way of these treatment options.
Scalp psoriasis is common and for many patients, is one of the more troubling places to have psoriasis. Fortunately, there are numerous options — both over-the-counter and by prescription — to help people treat scalp psoriasis. It may take someone a few tries to find something that works, but most people can find at least partial relief if they have persistence.
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