Contact allergy is psoriasis.

It has been suggested that allergic contact dermatitis (ACD) is uncommon in psoriasis, but associated with flexural and palmoplantar involvement. Previous studies have suggested an association between site and morphology of psoriasis and allergic contact sensitivity but it was found that a similar proportion of patients with and without positive patch test reactions had flexural, palmoplantar and chronic plaque psoriasis. Contact allergy to medicaments including dithranol has been recorded in psoriatics.