welcome to healthcaremagic
creams like betamethasone
,loratadine will only give her symptomatic relief.. and will not cure it will only suppress and worsen the condition..
skin diseases are very successfully cured with homeopathic medicines..
i will suggest you to consult a homeopath
the diagnosis will depend on the symptoms and presenting skin condition..
in psoriasis there is severe itching
and scaling of the skin..
if there is itching then apply olive oil..
and yes it is better to avoid sea food eggs and nuts and tangy things as it can aggravate the condition..
wishing her good health..