PUVA is a special treatment using a photosensitizing drug and timed artificial-light exposure composed of wavelengths of ultraviolet light in the UVA spectrum. The photosensitizing drug in PUVA is called psoralen. Both the psoralen and the UVA light must be administered within one hour of each other for a response to occur. These treatments are usually given in a physician's office two to three times per week. Several weeks of PUVA is usually required before seeing significant results. The light exposure time is gradually increased during each subsequent treatment. Psoralens may be given orally as a pill or topically as a bath or lotion. After a short incubation period, the skin is exposed to a special wavelength of ultraviolet light called UVA. Patients using PUVA are generally sun sensitive and must avoid sun exposure for a period of time after PUVA. Common side effects with PUVA include burning, aging of the skin, increased brown spots called lentigines , and an increased risk of skin cancer , including melanoma . The relative increase in skin cancer risk with PUVA treatment is controversial. PUVA treatments need to be closely monitored by a physician and discontinued when a maximum number of treatments have been reached.
Dithranol creams may be effective in scalp psoriasis but, like coal tar, can be difficult to use and are not often prescribed for home use. Dithranol is usually applied to the scaly plaques and left in contact for up to 30 minutes before being rinsed out. It needs to be applied with great care as it can irritate and cause purple staining of blonde or red hair. Dithranol can also burn skin unaffected by plaques. Lipid stabilised dithranol, if used correctly, can reduce staining. It should also be noted that dithranol will stain clothing and baths, showers and wash basins. Extra attention is needed and so it is probably best reserved for supervised use in dermatology clinics only.
It is always best to seek help from a GP or Dermatologist for psoriasis in sensitive areas. This is because psoriasis in these areas can be painful or particularly uncomfortable, can affect a person’s quality of life (such as their work, relationships and social life), and may be more prone to infection. Treatments that may have been prescribed for psoriasis on another area of the body are not always suitable for psoriasis in sensitive areas. Because of this, a separate treatment plan may be needed for these areas. Suitable treatment may only be available on prescription, and so a visit to a GP or Dermatologist is essential.