Psoriasis is an immune-mediated inflammatory condition that primarily affects the skin and the joints (psoriatic arthritis). It can have a devastating impact on the sufferer (though this is not always the case), because of the potent combination of physical symptoms and aesthetic concerns, which often leads to significant emotional distress. Here we take a look at some important aspects of this disease.
Is psoriasis always an autoimmune condition? What makes it autoimmune?
While some researchers believe there may be more to the picture, psoriasis is still considered solely an autoimmune condition at this time, and the mechanism of the disease (known as “pathophysiology”), while not fully understood, has been shown to involve a dysfunctional immune system.
Much like other autoimmune diseases, psoriasis is classified as such based on the fact that it appears to be the result of the body’s innate immune system attacking other cells and tissues mistakenly. In the case of psoriasis, many different parts of this system have been implicated. When the immune response is directed inappropriately, targeted tissues manifest this reaction in different ways. With psoriasis, the physical reactions between immune cells and normal tissues occur primarily in the skin, joints and nails.
What are the most common types of psoriasis?
There are several different forms of psoriasis, some of which are more common than others. The most prevalent type is known as chronic plaque psoriasis (also known as “discoid”), which causes red, scaly “plaques” to arise in certain areas; they are sometimes itchy, but not always, and tend to occur most frequently on the scalp, knees, elbows and back.
Then there is guttate psoriasis, where there is a sudden outbreak of small plaques; this is often associated with a Strep infection.
Inverse psoriasis is similar to the plaque variant, but with a different distribution of lesions, generally found in the folds of the body (armpits, buttocks, genitals, etc.).
Nail psoriasis, as the name implies, presents with psoriatic disease of the nail and nail bed, which causes distinct changes in nail color and structure.
In addition to those above, two more variants are seen with less frequency. Pustular psoriasis is an acute condition with multiple blister-like lesions (pustules) and systemic symptoms such as fever and malaise, and can range from mild to life threatening. Finally, there is erythrodermic psoriasis, a rare condition that manifests with red, scaly plaques from head to toe, and which can lead to problems with infection and electrolyte imbalance. Psoriasis also sometimes involves other organs and areas, such as the joints, liver and eyes.
The Mayo Clinic website offers an excellent overview of psoriasis, and the “symptoms” sections describes each kind noted above, with accompanying pictures, and the NIH provides information in a question and answer format.
What is considered mild, moderate and severe psoriasis?
For clinical treatment purposes, these are really split into two categories instead of three: mild-to-moderate and moderate-to-severe. These designations depend on the amount of total plaque area on the body, the severity of symptoms and their effect on activities of daily living. They may also be assigned according to whether there is involvement of joints or other areas, and degree of overall disability. In general, moderate-to-severe disease is present when greater than 5-10% of the skin surface is affected, with mild-to-moderate being anything less than this amount.
What are the signs/symptoms of psoriasis?
There are several variants of this disorder. For plaque psoriasis (the most common), the major manifestations are raised, reddened patches of skin (the plaques), some of which may itch or have a silver/gray scaly appearance. Scratching these areas will often result in more thickening of the skin. The plaques are generally not painful.
Other forms of the disease present with red lesions of varied size and appearance, in characteristic areas of the body, and/or with different timing, as noted above. The patient may have additional symptoms such as joint pain or eye inflammation, depending on the involvement of non-dermatologic systems. The American Academy of Dermatology offers a nice review of symptoms, according to subtype, compete with pictures.
Questions for your doctor:
- What type of psoriasis sub-type do I have? Is it possible to have more than one?
- Can I pass on psoriasis to my children?
- Can you tell me more about my treatment options? What is systemic vs. topical therapy? Are there any natural remedies?
- I always see that commercial for “sufferers of moderate-to-severe plaque psoriasis” on TV. What is that medication, and is it right for me?
- Does my disease or its treatment carry any truly dangerous risks to my health? If so, what are they?
- Can you recommend a source for accurate and easily digestible information?
About the Author
Dr. Rothbard is a professional medical writer and consultant based in New York City, specializing in medical education articles targeted at a variety of audiences, from children through clinicians. After leaving medicine, he worked as a biology and medical science educator for several years, before deciding to pursue writing full-time. He may be reached at [email protected].