Psoriasis is a common and chronic skin disorder that affects over 80 million people worldwide. It is prevalence in men and women and across all socio-economic groups. Psoriasis can develop at any age, although it commonly appears between the ages of 15 and 22. Females tend to develop psoriasis slightly earlier than males, and those with a family history also have an earlier age of onset. The disease can last for a short period of time or for a lifetime, with periods of relapses and remissions therefore difficult to predict the course of the disease.
Psoriasis is an inflammatory and proliferative disease of the skin that results in a rapid replication or turnover of the skin cells. The rapid replication of skin cells is more than 5 times of the normal rate, leading to thickening of the outer layers of the skins. Simple put, the skin cells replenishes itself faster than the shedding of the outer skins. This results patches of dull-red or pinkies thickened patches with silvery scales which are sometime known as lesions or plaques.
Psoriasis Plaque
Psoriasis on Scalp
Psoriasis on Knees
The common area where the disease presents itself are; elbows, knees, shins, scalp, fingernails, toenails, lower back and buttocks. Psoriasis also involves the groins, armpits, prineum and the area under the breasts, the lesions tend to be less scaly and rather shiny. Up to 50% of affected patients experience significant itch, especially on the scalp and lower legs.
In some cases, psoriasis is associated with psoriatic arthritis, a conditon similar to rheumatoid arthritis, that causes inflammation and stiffness in and around joints. About 15% of people with psoriasis will develop psoriatic arthiritis, and psoriatic arthritis can also be present without psoriasis.
Psoriasis causes is unknown, believed to have a genetic component and some link it to over active immune system. Several but common triggers include trauma, infection, and certain drugs. Diagnosis of psoriasis is based on appearance and distribution of the plaques.