(CNN) -- Psoriasis is an inflammatory skin condition that affects up to 5 million Americans. CNN learned more about psoriasis from Dr. Mathew Avram, director of the Massachusetts General Hospital Dermatology Laser and Cosmetics Center.
In psoriasis, patches of skin become raised and red and have a scaly top.
CNN: How would you know if you had psoriasis?
Avram: Commonly, people come in with these red, raised areas that have this silvery scale on top. The scale comes off very easily. A very characteristic sign of psoriasis is, when you peel off the scale, there's a little pinpoint area of blood in the middle of this, what we call a plaque.
CNN: What areas of the body are most affected by psoriasis?
Avram: Typically, the most common location to see psoriasis is on the hands and knees. Other areas are the scalp, the genitals, buttocks, palms and soles.
CNN: How is it treated?
Avram: While there are multiple treatments, unfortunately there's no one magic bullet. We have topical treatments, oral pills and phototherapy, which is light treatment. We have these new injections called biologics where actual proteins are injected into the skin to help combat psoriasis.
CNN: What about regular sunlight?
Avram: Sunlight is absolutely effective for psoriasis and in my patients, in spring and summer, they clearly tend to do better and in fall and winter they do less well because there's less sunlight. The one thing that I would caution patients about is that sunlight will help your psoriasis but you do increase your chances over time of potentially having skin cancer. So you want to do it in moderation and in consultation with your physician. You certainly don't want to overdo it, because there is a possibility of making it worse. Sunburn is something that's very uncomfortable.
CNN: Is psoriasis hereditary?
Avram: There is a genetic component to it. If one parent has psoriasis, there's an 8 percent chance that the offspring will have psoriasis. If both parents have psoriasis, it's about 40 percent.
CNN: Is psoriasis also related to the immune system?
Avram: It is. Basically, what you have in psoriasis is a hyper-proliferation of skin cells in the epidermis, the uppermost portion of the skin. There are numerous amounts of T-cells (a type of infection-fighting white blood cell) in the upper skin and that does play a role in causing the condition. That's why a lot of the treatments focused on improving psoriasis actually have as their goal the ability to decrease the amount of T-cells in the skin.
CNN: Are there triggers that can cause flare-ups of the condition?
Avram: There are certain triggers for psoriasis that patients should be aware of. There are lists of medications, including lithium. Other things are: injury to the skin, decreased sunlight, stress can also be a component.
CNN: Does psoriasis have a psychological impact on patients?
Avram: Yes, it's a disease that often lingers with patients for years. They can try various different treatments and the condition kind of waxes and wanes over time. As it comes back, it does take a psychological impact on the patients. Furthermore, the scaling and the appearance of the condition make it difficult for a patient to go to the beach or wear shorts. E-mail to a friend
Judy Fortin is a correspondent with CNN Medical News. Jim Morelli of Accent Health contributed to this report.
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