Psoriasis
It is the skin disease causes red, dry, itchy scaly patches most commonly on the knees, elbows, trunk and scalp. It tends to go through cycles , flaring for a few weeks or months, then subsides for a while.
Triggers
Infections
Weather , especially cold and dry conditions
Injury to skin
Stress
Smoking
Heavy alcohol consumption
Rapid withdrawal of Oral corticosteroids