Psoriasis -  Role of Methotrexate

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In 82 selected patients with psoriasis at the PGI, methotrexate (MTX) led to clearance of the lesions in nearly 80% in a mean period of 8 weeks, Dr. Kaur said in the Fulford oration at the 26th annual conference of the Indian Association of Dermatology, Venereology and Leprology.

With the stringent precautions taken, MTX therapy did not provoke adverse side effects such as hepatotoxicity, even when used in children and elderly patients to control severe disease episodes..

The aetiology of psoriasis is unknown but the disease has been found to have a genetic basis. On HLA phenotyping of the Chandigarh patients, a positive association was seen with HLA-B17 . However, familial occurrence was detected in only 2%.

The commonest lesions were plaques while pitting was the most common change seen in the nails. Arthropathy occurred in 4.4% of the patients. Sym metrical polyarthritis (RA like) was the most common type of arthropathy (33.3%). Geographical tongue in 3.8% and blepharitis in 5% were some of the other clinical signs.

Compared to the skin from controls, psoriatic lesions had a 4-fold elevation in the calmodulin levels, Dr. Inderjeet Kaur said. The directed chemotaxis of neutrophils was significantly increased in patients with psoriasis. Serum copper levels were higher while serum zinc levels were lower in psoriatics as compared to controls. Urinary tract cell counts were significantly higher in psoriatics.

Treatment

Although there is no known cure of psoriasis, the disease can be effectively controlled by various treatment modalities.

Majority of the patients respond to topical therapy which includes emollients, keratolytics, coal tar, anthralin and corticosteroids. The newer agents are topical PUVA, Topical Methotrexate, Calcipotriol and Tazarotene (a retinoid).

The mainstay of topical treatment of psoriasis is coal tar which was made popular by Goeckerman in 1925. Used for 8-10 hrs. (1%,5%,25%) is very effective.

Dithrano; ointment 0.5% to 1.15 % used for short periods of 30 minutes daily for 6 weeks results in complete clearance of lesions in 75 % of the patients. The only side effect being the perilesional skin staining.

Palmoplantar Psoriasis

Treatment of PPP which causes severe handicaps both cosmetically nd fuctionally presents particular challenge.

MTX gel 1 % was used twice daily for 8 wks. Good improvement was found in 80% of palmar and 64% of planter lesions.Topical MTX if used in a suitable vehicle that enhances percutaneous absorption and if used for a sufficient length of time has benificial effect on PPP.

Topical PUVASOL : The palms and soles of the patient was submerged in an 8-MOP soak solution for 15 munutes, followed by sun exposure immediately after drying. The treatment was given twice weekly for 8 weeks. 70 % palmar and 27 % planter cases shows good improvement. Only one patient had phototoxic reaction. PUVASOL is effective and safe therapy for palmar psoriasis.

Coal - tar therapy : 6 % crude coal tar (CCT), when used under occlusion , resulted in good improvement in 77 % of PPP patients.

Calcipotriol : Calcipotriol ointment 50 micg/g was used every night under occlusion for 8 weeks. Excellent improvement was seen in the palms.

Systemic Treatment

Sytemic treatment is reserved for patients with extensive disease or on whom conventional therapy has failed. Systemic therapy include PUVA, Conticosteroids,MTX, Hydroxyurea, Cyclosporine and Calcipotriol.

Before starting systemic therapy, patients undergo complete clinical and laboratory evaluation and only those with near normal renal, hepatic and marrow function are selected to receive MTX.

In the PGI series, 82 patients were given a single oral weekly dose of 0.4-0.6 mg/kg body weight of MTX. Nearly 80% clearance was seen in a mean period of 8 weeks. The drug could he completely withdrawn in 90% patients, coinciding with the seasonal remission. There was no response in 2 patients.. The commonest side effects were nausea and vomiting, which occurred in 30% patients.

Post- MTX disease free interval was 7.7 months. The drug had to he restarted in 13 patients while the others could be managed with topical therapy in the subsequent relapses.

MTX-free period of 4-6 months reduces the drug's hepatoxicity. MTX has also been used safely and effectively in children and elderly patients to control severe episodes of the disease.

Other systemic drugs tried included mesalazine, effective in about one-third of the pa- tients, oral nystatin, found to he ineffective, and cyclosporine, used in selected cases to tide over a crisis. Corticosteroids were found to have no role in routine treatment of psoriasis because of the risk of rebound.