Psoriasis is an inflammatory condition and chronic skin problem that come in a variety of forms. Depending on the cause and trigger factors, it can affect specific sites of the skin. However in severe case, it can affect large areas of the skin (more than 10 percent of the body). Plaques psoriasis is the most common type /form of the disease (it often occurs on scalp, lower back, knees and elbows).
It is commonly characterized by raised, red-color patches wrapped with a white-silvery buildup of skin cells (dead skin cells). Typically, they can be painful with itchy – even may crack and bleed.
In severe case, the lesions can grow and become larger. They can merge into one another – as a result, they may cover large areas of the skin.
When you have a rash on elbows or knees that doesn’t improve with an over-the-counter medication, it’s much better to see a doctor /dermatologist to get a clearly diagnosis and appropriate treatment.
A professional dermatologist is trained and educated to be able to diagnose skin problem (such as plaques psoriasis) on the basis of the symptoms & appearances of the lesions, the tendency of the lesions, and the distribution of the plaques.
Certain tests may be required, but typically additional tests such as blood test or biopsy are rarely used to make a diagnosis. Typically, the sample of biopsy for the affected skin with psoriasis looks inflamed & thicker than eczema (another common chronic skin condition).
But in general – many times, doctors can make the diagnosis with physical exam and the patient’s medical history.
Actually, the exact cause of psoriasis itself is not fully understood yet. In the initial development of the problem, there is also no clearly answer of why the disease affects specific sites of the skin such as knees or elbows.
As mentioned before, the disease comes in a variety of forms. And plaque psoriasis is only one of these forms.
Currently, experts believe that too fast skin cell production is the answer behind the disease. In psoriasis, skin cells can be produced 10 times faster than normal. This affects the normal skin cell’s life cycle.
These new skin cells then quickly move to the outermost layer of the skin. Dead skin cells don’t slough off quickly enough. As a result, they build up in thick, causing scaly patches on the surface of the affected skin.
Unfortunately, the cause of why this abnormal skin cell production is unclear. Experts only say that it may occur due to the combination of different factors.
The abnormality in the body immune system may be the key answer. However, some experts believe that this factor doesn’t work alone. Not all people with immune system disorder develop psoriasis.
Other factors may be required – these could be genetic traits and other external factors. In fact, many sufferers also have a family history of the same problem. This suggests that the disease is more likely to run in families.
For external factors, these may include obesity, emotional stress (see also the link between psoriasis and stress), smoking, injured skin, skin trauma to streptococcal infection, or viral /bacterial infections (such as HIV that can cause abnormality immune system).