By Amanda Barrell

Reviewed by Debra Sullivan, PhD, MSN, RN, CNE, COI

Psoriasis is a skin condition that causes some areas of skin to develop lesions. The appearance of psoriasis varies across different skin tones, and it can be more challenging to diagnose on black skin.

Psoriasis lesions tend to be thick and crusty, and they often form on the scalp, elbows, knees, and back.

In this article, learn about psoriasis on black skin, including its appearance and symptoms as well as how to treat it.

Prevalence of psoriasis in black people

Psoriasis is a common condition that affects more than 8 million people in the United States and 125 million people worldwide.

According to the National Psoriasis Foundation, it affects approximately 1.3% of African Americans compared with 2.5% of white people.

About one-third of people with psoriasis have a relative with the same condition, meaning that genetics is a risk factor.

Psoriasis usually appears between the ages of 15 and 25 years, but it can develop at any age. It is a long-term condition. While there is no cure, many treatment options are available to help manage the symptoms.

Symptoms

Psoriasis presents as thickened areas of skin, sometimes with an overlying scaly crust that may look shiny or silver. These lesions are usually itchy. If a person scratches them, they will bleed and scab over.

In black people, psoriasis can look violet or purple. The individual may also notice areas of darker, thicker skin. In both cases, the lesions can appear scaly. Lesions can develop anywhere on the body, including the scalp.

As psoriasis heals, it can leave areas of discoloration, which can take between 3 and 12 months to disappear.

Psoriasis tends to follow a relapsing-remitting pattern, meaning that people will experience a period of few or no symptoms and then a flare-up of more severe symptoms.

There are several different types of psoriasis, which can vary in their appearance. These are:

Chronic plaque psoriasis

Chronic plaque psoriasis is the most common form of the condition. It causes clearly defined lesions to develop on the elbows, knees, and scalp.

These red or violet lesions are between 1 and 10 centimeters (cm) in diameter and have overlying silvery scales.

Guttate psoriasis

Guttate psoriasis is more common in children or young people recovering from an infection, such as pharyngitis.

It causes small bumps less than 1 cm across to appear on the back, arms, and thighs.

Nail psoriasis

Some people with psoriasis only have symptoms on their nails. Nail psoriasis looks like tiny pinpricks on the fingernails or toenails.

The nails may also turn brown or become thick and crumbly.

Inverse psoriasis

Inverse psoriasis appears on less visible parts of the skin, such as the armpits, the buttocks, the groin, and the folds underneath the breasts. The lesions may be purple or darker than the surrounding skin.

Diagnosis

To diagnose psoriasis, a dermatologist will carry out a physical examination and ask questions about the lesions. They will probably also ask about any family history of psoriasis or related conditions, such as arthritis.

Psoriasis on black skin can be difficult to diagnose because it may resemble other skin disorders that are more common in black people.

In some cases, the doctor will also take a skin biopsy so that they can rule out other conditions.

Treatment

The treatment options for psoriasis are essentially the same regardless of skin tone, although some do carry special considerations for people with darker skin.

Standard psoriasis treatments include:

Creams and ointments

Creams and ointments are the first treatment option for most people with psoriasis.

The most commonly-used creams are steroids. Anthralin, synthetic vitamin D-3, and vitamin A products can also help manage psoriasis flare-ups. These tend to be available only with a prescription.

Over-the-counter creams for psoriasis include products containing aloe vera, jojoba, zinc pyrithione, capsaicin, or salicylic acid and coal tar.

Prescription medications

If creams and ointments do not work, a doctor may prescribe medications for psoriasis. These drugs are called systemic medications, and they may be in the form of pills, liquids, or injections.

Systemic medications include:

• acitretin
• cyclosporine
• methotrexate

The doctor may prescribe biologic drugs for moderate-to-severe psoriasis. People usually receive these drugs, which target specific parts of the immune system, as an injection or infusion.

Examples of biologic drugs include:

• TNF inhibitors, such as Enbrel (etanercept) and Humira (adalimumab)
• interleukin-12/23 inhibitors, such as Stelara (ustekinumab)
• the interleukin-17A inhibitor Cosentyx (secukinumab)
• T cell inhibitors, such as Orencia (abatacept)

Phototherapy

Phototherapy is also called light therapy. This treatment involves regularly exposing the skin to ultraviolet light under medical supervision.

Standing in a light box two or three times a week can cause the skin to tan or darken. The American Academy of Dermatology (AAD) warn that this may make dark spots on black skinmore noticeable.

Learn more about phototherapy for psoriasis in this article.

Management

There is no cure for psoriasis. Anything that irritates the skin can cause the condition to flare up. The AAD offer the following advice to avoid flare-ups wherever possible:

• avoid skin injuries, such as nicks, cuts, and bug bites
• protect the skinfrom sunburn
• use a cold compress and moisturize regularly to alleviate the itching
• avoid scratching itchy skin

People should also learn to recognize the triggers that lead to their flare-ups. These differ among individuals but can include:

• stress
• bug bites
• summer heat and cold winter weather

Some people with psoriasis develop lesions on their scalp so doctors may also recommend frequent shampooing with a medicated shampoo.

Summary

Psoriasis is a common skin condition that affects fewer African Americans than white people in the U.S.

In black people, psoriasis may look darker than the surrounding skin or might appear purple. In both cases, it tends to have a scaly overlay. Psoriasis lesions can appear anywhere on the body, including the scalp.

Anyone with symptoms of psoriasis should speak to a doctor about diagnosis and appropriate treatment options.