The Effect of Levocetirizine on Inflammatory Mediators in Dermatographism

Inclusion Criteria: 1. Patients with symptomatic dermatographism and chronic idiopathic urticaria. 2. Adult male and female between 18 to 60 years of age. 3. Signature of informed consent. 4. No known hypersensitivity to levocetirizine or to any of the ingredients of Xyzal® or to cetirizine. 5. Willingness to refrain from other antihistamines, prescription and and over- the-counter cough \& cold medications, topical creams, topical steroids and topical immunomodulators, for one week prior to the study. In very severe cases of CIU and dermatographism, based on dermatologist consultation and recommendation, and depending on the half-life of the prior antihistamine medication used, this period may be reduced to 3-4 three days. Rescue medication will be promptly provided if at any time the subjects will experience a significant relapse of their CIU symptoms. 6. Good general health. 7. Ability to understand and comply with the protocol. 8. Females of child-bearing potential must have a negative urine pregnancy test prior to randomization. 9. Absence of another active skin disease that may influence skin evaluation during the study. Exclusion Criteria: 1. Pregnant females, females planning on getting pregnant or breast feeding. 2. Uncontrolled chronic disease such as diabetes. 3. The presence of renal disease with a moderate or severe renal impairment (since Xyzal is primarily eliminated through the kidneys) as documented from medical records or patient history. 4. History of anaphylaxis, angioedema or allergy to Xyzal or cetirizine (Zyrtec). 5. Any systemic disease involving mast cells such as allergic rhinitis, lung disease, asthma or autoimmune collagen disease. 6. Severe vascular or neurological diseases that would impart an asymmetric blood perfusion or an impaired function of the arms.