Reduction of adverse effects by systemic antihistamines during therapy with fumarates in severe chronic plaque psoriasis.

1. Patients with known severe psoriasis of the chronic plaque type

2. PASI > 10

3. Age > 18 years

4. Psoriasis therapies cannot be administered starting from 28 days before baseline visit until discontinuation of the study medications at the end of the study.

5. All forms of ultraviolet light therapy are prohibited during the study through week 12, such as PUVA and UVB (including narrow band UVB and excimer laser). Puva is prohibited starting from 28 days before the baseline and UVB is prohibited starting from 14 days before baseline.

6. All forms of topical psoriasis therapies cannot be administered from 14 days before baseline until discontinuation of the study medications through week 12.

7. Investigational or biological drugs are not permitted from 28 days prior to screening visit until discontinuation of the study medication at the end of study.

1. Pregnancy and breast feeding

2. Patients with Prostate hyperplasia, Glaucoma, Stomach ulcer

3. Patients with liver diseases

4. Patients with kidney diseases

5. Patients with blood test deviations

6. Patients with gastro-intestinal diseases

7. Patients with a history of malignancies

8. Presence of clinically significant renal and hepatic laboratory values ( i.e.,male patients with serum creatinine ¡Ý 133 umol/L; female patients with serum creatinine ¡Ý 124 umol/L; ALT, AST, total bilirubin, GGT, or Alkaline Phosphatase > 2.5 times the upper limit of the reference range).

9. Serum lipase impairments (total cholesterol > 6.5 mmol/l, LDL-cholesterol > 2mmol/l, triglyceride > 3 mmol/l).

10. Hemoglobin parameters must satisfy the following criteria:

10.1 hemoglobin < 7.5 mmol/l

10.2 leukocytes > 3.50*10E9/l and < 10*10E9/l

10.3 lymphocytes > 15% and < 50% of the total white cell count.