Does psoriasis spread by scratching?

No, psoriasis does not spread by scratching. Psoriasis is a non-contagious skin condition, caused by an overactive immune system. Scratching can worsen the symptoms and cause the skin to become red and inflamed, but it does not lead to the spread of psoriasis. However, scratching can cause new psoriasis patches to appear, due to the Koebner phenomenon. This is a condition where skin trauma or injury triggers the development of psoriasis in previously unaffected skin areas.