ABSTRACT
Itching is the main symptom in urticaria and can cause a lot of suffering in chronic urticaria. To measure the itch threshold in patients with chronic urticaria before and after treatment and compare them with healthy control. The study was conducted at the department of dermatology, medical city teaching hospital Baghdad in the period from December 2009 to July 2010. A total of 30 patients with chronic urticaria [patients group] and 25 healthy individuals [control group], were included in the study. The age of patients ranged between 21years and 48 years with a mean of 30.96 years +/- 6.09 years [standard deviation]. In control group the age ranged between 20 years and 45 years with a mean of 31.40 years +/- 8.39 years [standard deviation]. Regarding gender, in the patients group 19 were females and 11 were males. While in the control group 14 were females and 11 were males. Electrical skin itch threshold was measured by square wave DC electrical stimulator at 13 points on the skin surface in patients and compared to the healthy controls. Doxepin was given to patients for 2 weeks, the itch threshold was then measured again. The severity of urticaria was also assessed before and after treatment. Patients with chronic urticaria had significantly lower threshold than the control subjects .The lowest threshold recorded in patients group was [1.292 +/- 0.399] volts in the left cheek, while in control group the lowest electrical cutaneous threshold was recorded in the chin [1.89 +/- 0.490] volts then left cheek [1.910 +/- 0.478]. The P-value was significance in all skin spots. The electrical cutaneous threshold increased after treatment in all spots tested after treatment. The increase was statistically significant in all tested the skin spots except in the back of the neck and xyphoid point. The total score decreased from 10.8 before treatment with doxepin to 1.5 after treatment. The individual parameters also decreased significantly after treatment. There were no significant side effects except drowsiness which improved after a few days even with continuation of treatment. Electrical skin itch threshold seems to be a simple test that aids in measuring the severity of itching in urticaria and may be used in the evaluation of drugs used for the alleviation of itching in urticaria and other skin diseases.