The cause of psoriasis is not yet fully understood but sources generally relate it with an immune system concern, specifically T cells and other white blood cells problem.
For instance, the T cells mistakenly attack healthy skin cells which leads to redness and scaly patches. The skin cells then multiply for about 10 times faster than usual. This condition is believed to be inherited and triggered by several factors such as skin infections and injury, stress, alcohol, smoking, vitamin D deficiency, and certain medications (beta blockers, lithium, iodides, antimalaria drugs, etc.). It is not contagious. The topical treatments include steroid-based creams, salicylic acid, coal-tar ointments, and retinoids. Other treatments include oral and injectable medications, phototherapy, and gluten-free diet.