While it is antihistaminics, topical and oral steroids
for eczema and antifungal
for fungal infection, the treatment of psoriasis that have been approved by FDA are adalimumab and Xtrac Velocity excimer laser system. Apart from that, topical medications like emollients, creams containing coal tar, dithranol, corticosteroids, fluocinonide, vitamin D3 analogues and retinoids have been routinely used.
So before using any treatment it is advisable to consult a dermatologist.
I hope it helps.