Dear Doctor
What are the causes of psoriasis?
Dear Patient
Factors which contribute to the development of psoriasis lesions include:
Genetic Factors
Genetics are known to play a role in the pathogenesis of psoriasis. For example a child with one parent with psoriasis has a 1 in 4 chance of developing it.
Psoriasis is however a complex genetic disease since many genes are involved in its inheritance. In addition, inheriting the right psoriasis gene combination does not guarantee that the disease will appear in that person.
Immunological Factors
Immunological factors also have a role to play since research suggests that psoriasis is an autoimmune disease.
The active lesions of psoriasis are associated with excessive activity of T-cells which are a type of white blood cells. These cells trigger the abnormal inflammation and rapid turnover of skin cells associated with psoriasis.
Environmental Factors
Environmental factors are other “causes of psoriasis” since they can trigger the appearance of psoriasis lesions in persons who are genetically predisposed to developing them. Therse factors include:
1. Infections like:
a. Throat infections especially those caused by streptococci
2. Medications like:
a. Antimalarials like chloroquine
b. Beta blockers used to treat high blood pressure and angina chest pain
3. Trauma
Injury to the skin from cuts, scratches and sunburns can cause psoriasis lesions to develop. When psoriasis develops on skin that has been injured it is known as the Kobner phenomenon.
In many patients no cause or reason for developing psoriasis is found.
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