Psoriasis

Must not donate if:
a) Generalized or severe.

b) There is secondary infection.

c) Immunosuppressed

a) If the quality of the tissue being donated is not affected, accept

b) If mild and only using topical treatment, accept.

c) If the donor is on immunosuppressive medication, see Immunosuppression entry.

Psoriasis is primarily a skin condition caused by an autoimmune process. About one in ten people with psoriasis may develop joint problems (psoriatic arthropathy). Sometimes the disease is treated with powerful drugs to suppress the underlying autoimmune process. This may alter the body's defence mechanisms to infection. 
Donations may be accepted if the safety and quality of the tissues is not affected.

Autoimmune Disease
Immunosuppression

Treatment with Etretinate/Neotigason is no longer a reason for deferral. To clarify that if there is no involvement of the tissue to be donated, donation may proceed. Link to ‘immunosuppression’ entry added.