I found this information for you on the net by doing a search on nail psoriasis. I will also say that fish oil contains the same properties as jojoba oil in that the molecular structure is very tiny, which will allow it to penetrate the surface layer of the skin and nails. Jojoba oil's molecule is actually smaller than that of fish oil, so therefore, can penetrate deeper. I might suggest you use a mixture of jojoba oil, vitamin E oil and sweet almond oil. This combination of oils will allow for deep penetration of the oil, while also having the additional benefits of vitamin E's healing and 'anti-aging' properties, along with conditioning and moisturizing benefits of the jojoba and sweet almond oil. Keeping the nail plate super-hydrated can help to prevent nail plate crumbling which is a result of acute nail psoriasis.
"There is no cure for nail psoriasis but it may improve by itself and may even return to a normal appearance. Although nail psoriasis is a benign condition, it can be uncomfortable and look unsightly causing significant dysfunction and psychological distress.
Several treatment options are available. Currently no one option has been identified as the best and all of them may prove disappointing. Treatment depends on the site and severity of the nail disease in individual patients.
Calcipotriol solution applied twice daily to the nail folds is safe to use and may help nail psoriasis if applied over prolonged periods
Topical high-potency corticosteroid solution or ointment works best when covered by cellophane wrap at bedtime. Avoid prolonged occlusion (2 weeks at most) or continuous therapy with corticosteroids.
Intralesional triamcinolone acetonide injected into proximal nail folds is helpful (but painful) in nail matrix psoriasis.
Topical 5-fluorouracil cream applied to the matrix for 6 months may improve pitting and subungual hyperkeratosis.
Psoralen and UVA (photochemotherapy or PUVA) may improve nail psoriasis.
Systemic treatment with oral methotrexate, retinoids and cyclosporin is usually prescribed for generalised psoriasis but may also be helpful for nail disease.
Antifungal treatment may be prescribed if secondary infection is present.
Chemical or surgical avulsion therapy, i.e. complete removal of the nail, is rarely recommended. The regrowing nail may be as badly or worse affected than prior to the procedure."