Are there any natural treatments for psoriasis?

Yes. Psoriasis is an immune system disorder and most treatments are aimed at suppressing the immune system to improve the condition. A natural substance that suppresses the immune system is sunlight. Some patients tell me that vitamin c and vitamin e topically and orally help. Vitamin d is often incorporated into prescription creams. Recent studies have shown excess weight contributes to psoriasis.
Coal tar. Coal tar (available as a shampoo or cream or ointment) can smell and stain, but can be effective treatment for psoriasis in some people. No prescription is needed.
Natural skin care. The skin is very sensitive, and a good marker for many aspects of health. Any skin condition can suggest imbalance in diet, sleep or how one handles stress. Addressing these issues can help, as can staying hydrated. Specific treatments include topical vitamin d, evening primrose oil (essential fatty acids), and burdock root. Please be aware psoriasis can be more serious than just a skin problem.