What is Psoriasis?
Psoriasis is a skin problem that lots of people have. It can result in bumpy red patches covered with white scales. However, in people with darker skin tones, the appearance may differ slightly. 

Discoloration: The red or pink patches of skin typical in light-skinned individuals may appear darker brown or violet in individuals with skin of color. 

Scaling: The silvery-white scales characteristic of psoriasis may not be as noticeable or may appear grayish in color on darker skin.

Pigmentation changes: Dark spots (post-inflammatory hyperpigmentation) or light spots (hypopigmentation) may occur after psoriasis lesions heal.

Distribution: Similar to individuals with lighter skin, psoriasis in people with skin of color often affects the scalp, elbows, knees, back, face, palms and soles.  

Psoriasis can begin at any age, most commonly by age 30, although it is less common in children than in adults.

There are several types of psoriasis, some of which are described below:

Plaque psoriasis
This is the most common type. It presents symmetrically on the elbows, knees, and scalp. The plaques are red or violet in color, with a thick silvery scale creating a sharp border between the plaque and normal skin. These plaques can range from 1 to 10 cm in diameter.

Guttate psoriasis
These spots are small (usually smaller than the size of a pea) and show up suddenly as little bumps on your back, arms, and thighs. Guttate psoriasis often happens in kids or young adults and is linked to recent infections, like strep throat.

Nail psoriasis
Sometimes people with psoriasis will develop nail problems, which may be the only sign of psoriasis. Nail pits develop, presenting as tiny pin pricks on the nail. In addition, the nails may become thick and crumbling, and develop a brown color known as “oil spots.”

Inverse psoriasis
Unlike regular psoriasis which often appears on the knees and elbows, inverse psoriasis shows up in places that are not easy to see. It can appear under the arms, in the folds of the buttocks, in the groin area, and under the breasts.  Because it looks different from typical psoriasis, it can be mistaken as a fungal or bacterial infection.

Psoriatic arthritis
Although psoriasis mainly affects the skin, it can also impact the joints. Pain and stiffness of the joints (especially along the hands, knees, and back) is common. Nail psoriasis is a common finding in individuals with psoriatic arthritis. 

What causes Psoriasis?
Psoriasis is a complex condition. While its exact cause is not entirely understood, it is believed to be related to an immune system problem with T cells and other white blood cells (called neutrophils) in the  body. Typically, T cells travel through the body to defend against foreign substances, such as viruses or bacteria. But if you have psoriasis, the T cells mistakenly attack healthy skin cells (as if to fight an infection) contributing to inflammation of the skin.  

The condition is also considered genetic, as it tends to run in families. In addition, certain factors can trigger psoriasis and make it worse, such as bacterial infections, stressful life events, dietary factors, trauma, and changes in the weather (especially cold, dry conditions).

How do I know if I have Psoriasis?
Dermatologists (or skin doctors) can examine the skin and may also take a small sample of the skin (or a skin biopsy) to rule out other diseases.

How is Psoriasis Treated?
There are many treatments that can help with psoriasis. The treatment depends on the type of psoriasis and how severe it is . While psoriasis cannot be cured, the symptoms can be managed with therapy. Moisturization, with petroleum jelly or thick creams, is key to keeping the skin soft and moist in order to reduce itching. Certain medications such as calcipotriene or calcitriol are related to Vitamin D and have been shown to help keep psoriasis under control. Tazarotene (which is similar to Vitamin A) can also be prescribed by a dermatologist for mild psoriasis or psoriasis that affects only a few areas on the body. A dermatologist may also prescribe a topical corticosteroid to reduce inflammation. If topical therapies are not sufficient, ultraviolet light (phototherapy) could be effective with minimal side effects (like  pigmentation changes–see section on “What is Psoriasis?”). As psoriasis is an immune-related condition, certain shots or infusions (biologic agents) can be given as well to help your immune system.