7 Answers About Psoriasis

Have you or someone you know been diagnosed with psoriasis? Here are a few questions you may have, with answers from a dermatologist.

1. What Is Psoriasis?

Psoriasis is an autoimmune disease that affects 7.5 million people. The scaly patches that characterize the condition occur when the immune system incorrectly speeds up the growth cycle of skin cells.

"Psoriasis is a varied condition that often runs in families," notes Joyce Davis, MD, a dermatologist in New York City. "It can consist of widespread pink, scaling spots on the skin that look like continents, or it can be localized to just a few spots. It usually isn’t itchy and it often appears on hands, feet, knees, elbows, and the scalp, though it can crop up almost anywhere. It can also involve just the joints (called psoriatic arthritis) without causing any skin lesions."

2. How Did I Get Psoriasis?

We don’t know exactly what causes psoriasis, but we do know it’s a combination of genes and environmental cues. Psoriasis may flare when the immune system reacts to any number of triggers, including stress, an infection, or certain medications. Psoriasis is not contagious.

3. How Is Psoriasis Diagnosed?

A dermatologist makes the diagnosis based on the skin’s appearances and sometimes by looking at skin cells under a microscope. There are no blood tests that diagnose psoriasis.

4. What Kind of Psoriasis Do I Have?

According to the American Academy of Dermatology:

  • 80-90 percent of psoriasis cases are plaque psoriasis, which is characterized by patches of raised, reddish skin covered with silvery-white scales.
  • Up to 40 percent of patients have psoriatic arthritis.

Other forms of psoriasis include:

  • Inverse (red lesions that appear in skin folds)
  • Erythrodermic (a rare, severe form that causes widespread, painful, “fiery,” itchy lesions)
  • Pustular (blisters filled with white pus)
  • Guttate (small dot-like lesions)
  • Nail disease

5. How Bad is my Case?

Psoriasis can be mild, moderate, or severe, depending on how much of the skin and body are affected. Mild cases cover less than 3% of the body, moderate cases cover 3-10%, and severe cases cover more than 10%, according to the National Psoriasis Foundation.

6. How Is Psoriasis Treated?

"Treatment depends on the extent and severity of the disease," Davis says. "For localized, mild cases, treatment with a topical cream or ointment is often sufficient. Potent corticosteroids [topical treatments that contain steroids, which act as anti-inflammatories] are usually the starting drugs. There are also non-cortisone alternatives, such as drugs with vitamin D, tar, and calcineurin inhibitors [medications that suppress the immune system to prevent production of cells that cause psoriasis—popular ones include Protopic and Elidel]. When the scalp is involved, corticosteroid mousses (foams), liquids, and gels are less greasy than creams or ointments. Some patients choose cortisone injections for scalp patches to alleviate the mess of medications. For more widespread disease, we prescribe oral medications."

She continues, "Traditionally, dermatologists used methotrexate and cyclosporin," both of which suppress the immune system. "But now, there are newer biologic agents [protein-based drugs that block the action of specific immune cells that play a role in psoriasis development]. They come in oral, injectable, and infusible forms and provide better control." However, "Different medications target different aspects of psoriasis, and some might have to be avoided if certain underlying medical conditions exist," Davis adds.

Finally, "Keep in mind that most of the newer medications are expensive, and medication choices may have to be dictated by what you can afford or your insurance carrier will allow. The biological agents are cost-prohibitive unless your insurance carrier covers them or you qualify for programs that cover medications for those in need."

7. How Long Will Treatment Take to Work?

That depends on how well you follow your treatment plan and whether a specific medication is the right choice for your condition. In general, give a new treatment 8–12 weeks to kick in and do its job.

Davis, Joyce, MD, reviewed this article.


Davis, Joyce, MD. Email interview March, 25, 2016.

"Fact Sheet: You and Your Doctor." National Psoriasis Foundation. August, 2015.

"Psoriasis." American Academy of Dermatology. Accessed April 4, 2016.

"About Psoriasis." National Psoriasis Foundation. Accessed April 4, 2016.

"Systemic Medications: Cyclosporine." National Psoriasis Foundation. Page accessed May 6, 2016.

"Psoriasis and the Flu: What you Need to Know if you Are Taking an Immunosuppressive Drug." National Psoriasis Foundation. Page accessed May 6, 2016.