what causes psoriasis

Causes and risk factors

The cause of psoriasis is unknown, but is often a positive family history, suggesting a genetic component in many cases (family antecedents of psoriasis are identified in a third of cases).
Psoriasis mechanism corresponds to accelerated renewals of the epidermis cell  (the top layer of skin) every 4 days, though normal cycle is 28 days. Given because life of the cells is the same, they form and accumulate thick crusts.
Although the cause is not known precisely, we identified factors that triggers psoriasis:
- stress
- streptococcal infection ( Beta-hemolytic )
- Local irritation (Koebner phenomenon)
- stopping treatment with some medications (cortisone)
- some medications (chloroquine, beta blockers, indomethacin, lithium, interferon alpha)
- sunburns
- Ingestion of toxic substances (alcohol, tobacco, etc.)
- Sleep disorders

Risk Factors

- Genetic predisposition - over a third of patients, one or more family members also suffer from psoriasis. If a parent shows this condition, the risk to the child varies between 5 and 10%.
- Immunological reactions against another disease (chickenpox)
- Reaction to a medication (lithium, beta-blockers) or vaccine
- A systemic infection (pharyngitis or streptococcal angina)
- stress
- Skin lesions
- Dry climate
- Prolonged exposure to sunlight or certain chemical substances ( paint thinners or disinfectants)
- Excessive alcohol consumption.