Hello. Thank you for writing to us at healthcaremagic
Since you seem to have a generalized involvement with psoriasis; this type of involvement is also known as
erythrodermic psoriasis Or unstable psoriasis.
This type of psoriatic involvement is associated with thermoregulatory as well as metabolic complications as a result of the lack of normal temperature regulatory functions of the skin as well as loss of proteins, and fluids from the skin.
In general unstable forms of psoriasis like erythrodermic,
pustular psoriasis is managed conservatively with topical emollients and Oral / Systemic Immunosuppressives like
Methotrexate, Cyclosporin etc.
Before starting on PUVA, patients skin is tested for the tolerable effective dose of PUVA, known as MED (minimal
erythema dose). The starting dose of PUVA is then calculated as 75% of MED. However, if all of the skin is already red, there cannot be an accurate determination of MED.
Therefore, if inadvertant higher doses of PUVA are given in erythrodermic psoriasis without calculating MED, PUVA can further irritate the skin and therefore is not the first choice amongst
dermatologist in unstable psoriasis.
Nevertheless, PUVA can be given in low doses along with other systemic treatment like methotrexate, cyclosporin etc even in erythrodermic psoriasis.
Regards