Psoriasis is a chronic condition that causes an overproduction of skin cells, leading to scaly skin and red lesions. Psoriasis of the scalp appears in about half of all people with psoriasis. Though there is no cure for psoriasis, treatments are available to manage the condition. According to "The Science of Hair Care," castor oil is gentle and moisturizing, and can ease the discomfort of psoriasis of the scalp. You can safely use this treatment as often as you desire, though weekly treatment is enough for many people to notice favorable results. If you continue to experience symptoms associated with psoriasis on your scalp, consult your physician for further guidance.

Apply a generous amount of castor oil to your scalp before going to bed. According to the book, "The Science of Hair Care," castor oil is hydrating to both the hair and the scalp. Gently massage the oil into your scalp. According to the book, "Hair and Hair Care," massaging the scalp promotes circulation, which allows the scalp to better absorb the castor oil.

Don a shower cap, place your pillow in a garbage bag and wrap it in a thick towel to ensure that your linens remain free of the castor oil while you sleep.

Wash and shampoo your hair as you normally do to rinse out all of the excess castor oil. Gently massage your scalp to promote healthy circulation as you wash and rinse your hair and scalp.