Psoriasis and Psoriatic Arthritis

The cause of psoriasis is unknown, but research indicates that it may be related to an abnormality in immune system functioning that triggers inflammation in the skin causing skin cells to shed too rapidly, every 3 to 4 days instead of the normal 30-day cycle.

Common Triggers

A “trigger” is usually needed for psoriasis to appear. Common triggers include:

  • Stress
  • An infection, such as strep throat
  • Taking certain medicines, such as interferon or lithium
  • Cold, dry weather and lack of sunlight in winter
  • Skin injuries, such as a cut, scratch or severe sunburn

Types of Psoriasis

The five major types of psoriasis each have unique signs and symptoms:

  • Plaque Psoriasis is the most common type producing patches of red, thickened skin with silvery scales most often on the scalp, elbows, knees and lower back though it can affect any part of the body.
  • Guttate Psoriasis usually affects children and young adults with small, red spots appearing, often following a sore throat. It frequently clears without treatment in weeks or a few months.
  • Pustular Psoriasis is characterized by white pustules surrounded by red skin. Localized pustular psoriasis is confined to certain areas of the body, usually the palms and soles. When the skin affected is widespread, the condition is known as “generalized pustular psoriasis, which is a rare, severe form of psoriasis that can be life-threatening.
  • Inverse Psoriasis causes smooth, red lesions to form in skin folds, such as the armpit, under the breasts and around the groin, buttocks and genitals.
  • Erythrodermic Psoriasis can be life-threatening causing widespread redness with severe itching and pain.

Psoriasis frequently affects the scalp and nails. On the scalp the silvery-white scale produced may be misdiagnosed as dandruff. Psoriatic nails often have tiny pits and may become loose, thick or crumbly, all signs that may be misdiagnosed as a nail infection. Both scalp and nail psoriasis can be difficult to treat.

Psoriatic Arthritis

Between 10 and 30 percent of people who have psoriasis will develop a lifelong condition called psoriatic arthritis that causes inflammation in the joints leading to pain, stiffness and joint deterioration. Early treatment with medication can help prevent joint deformity and disability. Without treatment, permanent joint degeneration and destruction can occur.

Diagnosis and Treatment

Dermatologists diagnose psoriasis by examining the affected areas of the skin. A biopsy may be ordered to confirm the diagnosis.

While there is no cure for psoriasis, your dermatologist can recommend a treatment plan that is appropriate for you depending on your health, age and the severity of your psoriasis to help control the condition.

Treatment options include topical medications applied to the skin, various types of light therapy and systemic medications including biologic agents.

Topical Medicines

  • Corticosteroids or cortisone is a medication that reduces inflammation to help clear the skin temporarily and control psoriasis in many patients. Due to potential side effects, cortisone should be used cautiously as directed by your dermatologist. Stopping the medication may cause a flare-up of the condition and psoriasis may become resistant to the cortisone after long-term use meaning the medication will no longer be effective.
  • Anthralin, which decreases the rapid growth of skin cells and reduces inflammation, is often effective on thick patches of psoriasis that can be difficult to treat. Newer forms of anthralin treatment have fewer side effects, such as skin staining or irritation.
  • Calcipotriene is used to treat localized psoriasis and may be combined with other treatments. Apply as directed to avoid skin irritation and other side effects.
  • Coal tar has been used to safely and effectively treat psoriasis for over 100 years. Coal tar products used today are greatly improved and less messy. Stronger preparations can be prescribed for treating difficult areas.

Light Therapy

Ultraviolet (UV) light slows the rapid growth of skin cells associated with psoriasis. Most types of light therapies can be administered in your dermatologist’s office. Under a dermatologist care, light therapy can be a safe and effective option for treatment. Self-treatment by sunbathing or using artificial UV lights is not recommended without advice and instructions from your dermatologist.

Depending on the severity of the condition and other variables, your dermatologist may recommend one of the following types of light therapy:

  • Ultraviolet B (UVB) treats psoriasis by exposing the skin to ultraviolet B light. It may be used alone or in combination with other treatments. About 24 treatments over a two-month period are usually needed for clearing the skin.
  • PUVA is used to treat psoriasis that is widespread. The therapy combines the medication psoralen, taken orally or applied to the psoriasis with exposure to a carefully measured special form of ultraviolet A (UVA) light. Patients must wear UVA blocking glasses when exposed to sunlight for the rest of the day after treatment. Clearing usually occurs after 25 PUVA treatments given over two to three months. Maintaining control of the psoriasis can require 30 to 40 treatments a year.
  • Goeckerman treatment is a therapy used to treat severe psoriasis that combines coal tar dressings with daily exposure to UV light for a prescribed amount of time. The treatment, named for the dermatologist who reported it, is available only in a few specialized centers in the United States. 

Though all light therapies are generally safe and effective, patients should discuss potential side effects with their dermatologist.

Systemic Therapies

Systemic therapies are medications that spread through the bloodstream to reach and affect cells throughout the body. Because of the potential for serious side effects, systemic therapies are usually reserved for psoriasis that has not responded to other treatments. All these therapies also require close medical monitoring of the patient, including regular blood testing and other tests performed throughout the treatment period. Some of these therapies should not be used by pregnant women or partners of either sex trying to conceive a child. Your dermatologist will discuss the risks and benefits of the systemic therapy recommended for you to ensure that you understand your treatment options and any precautions that may be necessary.

  • Methotrexate is an anti-cancer medication that can dramatically clear moderate to severe psoriasis.
  • Retinoids taken orally may be prescribed alone or used in combination with ultraviolet light for severe cases of psoriasis.
  • Cyclosporine is a medication that suppresses the immune system and is used to prevent organ rejection in transplant patients. It has proven extremely effective in treating patients with severe psoriasis. 

Biologic Agents

Biologics are systemic medications that pinpoint precise immune responses involved with psoriasis. Careful consultation with a dermatologist and extensive medical testing are important to find the most appropriate biologic treatment. The following biologics may be prescribed for psoriasis:

  • Alefacept treats moderate to severe chronic plaque psoriasis by blocking over-activated T-cells. The medication is administered by a medical professional using intramuscular injections, typically one injection per week for 12 weeks.
  • Etanercept works to treat both psoriasis and psoriatic arthritis by blocking a part of the immune system that directs cells to cause the inflammation that leads to psoriasis. Used as a long term therapy, etanercept is given by injections, which patients can learn to give themselves.
  • Efalizumab is another long-term therapy that can improve psoriasis by blocking activation of T-cells in the immune system. With instruction, patients can give these injections to themselves.
  • Infliximab treats psoriasis and psoriatic arthritis by an immune system component called TNF- a. The medication is given by infusion in a medical office.
  • Adalimumab also blocks TNF- a and is effective for treatment of psoriatic arthritis. Adalimumab is given by injections which patients can learn to give themselves.

Though psoriasis cannot be completely cured, treatment can reduce the effects psoriasis has on your quality of life. Because many treatment options are available, it is important to partner with a board certified dermatologist, such as the doctors at Dermatology and Skin Surgery, to find a treatment plan that works for you.