US Pharm. 2018;43(6):13-14.

Immune System Attacks the Skin

Psoriasis is a chronic, noncontagious condition that affects the skin of over 7.5 million people in the United States. It occurs when the immune system signals a higher than normal rate of skin-cell production. Under normal conditions, it takes 2 to 3 weeks for new skin cells to develop fully. In the case of psoriasis, new skin cells mature every 4 to 7 days. As skin cells mature, they move to the surface, where they are shed from the body as dead cells. In psoriasis, this rapid turnover of new cells means that more skin cells, including cells that are still alive, reach the surface and are not shed as rapidly from the body, piling up on top of each other.

Symptoms Vary by Psoriasis Type

There are five different types of psoriasis: plaque (most common), guttate, inverse, pustular, and erythrodermic. Each presents with different symptoms. Plaque psoriasis is marked by itchy, red, thick, scaly patches, usually on the knees, elbows, lower back, or scalp. Guttate psoriasis causes small red spots, usually on the trunk or the limbs, and is often triggered by a bacterial or viral infection. Pustular psoriasis causes pus-filled bumps on the soles and palms, and may also present with fever, chills, severe itching, muscle weakness, and exhaustion. Inverse psoriasis appears as sore, red patches where skin touches skin, such as under the arms, in the groin, and under the breasts in women. The most serious, and potentially life-threatening, form is erythrodermic psoriasis. The skin all over the body turns bright red, the heart rate increases, and the patient has difficulty maintaining normal body temperature. Erythrodermic psoriasis requires immediate medical attention.

Psoriasis is not contagious and is not passed from person to person through touching. Although the exact cause of psoriasis can vary, evidence suggests that a combination of genetic factors predisposes certain individuals to the disease. In most cases, an external trigger is also involved in the development of psoriasis. Some common triggers are infections, skin injuries, stress, smoking, heavy alcohol use, vitamin D deficiency, and certain medications. Almost 30% of people with psoriasis develop another condition, called psoriatic arthritis. Psoriatic arthritis is marked by joint pain, stiffness, and swelling, which may include periods of more intense symptoms, called flares.

Treatments Include Light Therapy and
Topical/Oral/Injectable Medications

Doctors choose the individual treatment based on the type and severity of psoriasis and the areas of the skin that are affected. The treatment goal for psoriasis is to reduce inflammation and itching, slow the growth of skin cells, and clear up the skin by removing dead skin cells.

Lotions, creams, and ointments are applied to the skin directly and have been shown effective for mild or moderate psoriasis. With more severe symptoms, topical medications are combined with other types of treatments. Because ultraviolet B (UVB) light penetrates the skin and can slow the growth of affected skin cells, doctors may prescribe regular exposure to natural or artificial light to control symptoms of psoriasis. Light therapy usually involves regular, scheduled sessions of UVB light exposure, either via natural sunlight or using special lights or lasers.

Biologics Target Cell Growth

Many of the recent advancements in the treatment of psoriasis have been in the introduction of new oral and injectable medications for moderate-to-severe psoriasis. These medications, called biologics, are protein-based drugs developed from living cells that target specific parts of the immune system to control the rapid growth and movement of skin cells. The biologics approved for the treatment of moderate-to-severe psoriasis include etanercept (Enbrel), infliximab (Remicade), adalimumab (Humira), ustekinumab (Stelara), golimumab (Simponi), apremilast (Otezla), secukinumab (Cosentyx), and ixekizumab (Taltz). Most of these drugs are injections (apremilast is oral) used for people who have failed to respond to traditional therapy or who also have psoriatic arthritis. If you have any questions about psoriasis or about the medications used to manage it, speak with your trusted local pharmacist or another healthcare provider.

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