What is scalp psoriasis?

Psoriasis affecting the scalp is quite common among those living with psoriasis, and affects up to 45-56% of psoriasis patients.¹ It can be associated with any of the subtypes of psoriasis, but is most commonly seen in people with plaque psoriasis. The condition can present as just a single patch, multiple patches, or it can cover the entire scalp. Interestingly, the scalp is the most common place for psoriasis to first appear in children.² Its triggers are very similar to the other types of psoriasis, including certain medications, abruptly starting or stopping medications, infections, injury to the skin, stress, and tobacco or alcohol use.³

Symptoms

Scalp psoriasis is characterized by red, well-defined, and thickened skin covered in a thick scale. The scale is silvery and often looks like dandruff. The psoriatic lesions may extend beyond the hairline and be more visible in some cases. Itchiness and excess scaling are the most common symptoms that people experience. Most people with scalp psoriasis do not experience any hair loss, but it can occur in more severe cases, often due to scratching and excess combing.⁴

Diagnosis

Scalp psoriasis is clinically diagnosed, meaning that your doctor will take a thorough medical history and do a full physical examination, including taking a close look at your skin and scalp. They may ask you questions about when or how you first noticed your lesions, what symptoms you have, and if other parts of your body are affected.⁵

A skin biopsy, where a small sample of the lesion is sent to the pathologist to view under a microscope, is generally unnecessary for diagnosis.⁶ Some other conditions that can look like scalp psoriasis include seborrheic dermatitis, contact dermatitis (from irritating hair products like certain shampoos, hair dye, or gels), or a fungal infection, and can also leave dry flakes on your scalp. People with scalp psoriasis have also been found to have a higher likelihood of developing psoriatic arthritis, so your doctor may ask you about and examine your joints as well.⁷

Treatment

The treatment of scalp psoriasis can be a bit more challenging than other types of psoriasis because hair protects the scalp from UV phototherapy treatment and makes the application of topical therapies difficult.⁴ Even so, topical therapies are still the primary form of treatment for scalp psoriasis. These include things like topical corticosteroids and calcipotriol, as well as medicated shampoos. Phototherapy can still be tried in patients for whom topical agents have not worked, and oral therapies are generally reserved for patients who have not had success with topical or phototherapy treatments.⁸

References

1. Merola JF, Li T, Li W-Q, Cho E, Qureshi AA. Prevalence of psoriasis phenotypes among men and women in the USA. Clin Exp Dermatol. 2016;41(5):486-489.
2. Thomas J, Parimalam K. Treating pediatric plaque psoriasis: challenges and solutions. Pediatric Health Med Ther. 2016;7:25-38.
3. Wilson FC, Icen M, Crowson CS, McEvoy MT, Gabriel SE, Kremers HM. Incidence and clinical predictors of psoriatic arthritis in patients with psoriasis: A population-based study. Arthritis & Rheumatism. 2009;61(2):233-239.
4. van de Kerkhof PC, de Hoop D, de Korte J, Kuipers MV. Scalp psoriasis, clinical presentations and therapeutic management. Dermatology. 1998;197(4):326-334.
5. Kim WB, Jerome D, Yeung J. Diagnosis and management of psoriasis. Can Fam Physician. 2017;63(4):278-285.
6. Johnson MAN, Armstrong AW. Clinical and histologic diagnostic guidelines for psoriasis: a critical review. Clin Rev Allergy Immunol. 2013;44(2):166-172.
7. Busse K, Liao W. Which Psoriasis Patients Develop Psoriatic Arthritis? Psoriasis Forum. 2010;16(4):17-25.
8. Blakely K, Gooderham M. Management of scalp psoriasis: current perspectives. Psoriasis (Auckl). 2016;6:33-40.