Chronic urticaria (CU) is clinically defined as the daily or almost daily presence of wheals on the skin for at least 6 weeks.1 Chronic urticaria severely affects patients’ quality of life and can cause emotional disability and distress.2 In clinical practice, CU is one of the most common and challenging conditions for general practitioners, dermatologists, and allergists. It can be provoked by a wide variety of different causes or may be the clinical presentation of certain systemic diseases3,4; thus, CU often requires a detailed and time-consuming diagnostic procedure that includes screening for allergies, autoimmune diseases, parasites, malignancies, infections, and metabolic disorders.5,6 In many patients (up to 50% in some case series), the cause or pathogenic mechanism cannot be identified, and the disease is then classified as chronic idiopathic urticaria (CIU).7
It has previously been shown that contact sensitization could have some relation with CIU,8 which was further explored in this study. This study sought to evaluate if contact allergy may play a role in disease development in CIU patients in Saudi Arabia and if patch testing should be routinely performed for CIU patients to determine if any allergens can be avoided.
Methods
This prospective study was conducted at the King Khalid University Hospital Allergy Clinic (Riyadh, Saudi Arabia) in patients aged 18 to 60 years who had CU for more than 6 weeks. It was a clinic-based study conducted over a period of 2 years (March 2010 to February 2012). The study protocol was approved by the local ethics committee at King Khalid University Hospital. Valid written consent was obtained from each patient.
Patients were excluded if they had CU caused by physical factors (eg, hot or cold temperature, water, physical contact) or drug reactions that were possible causative factors or if they had taken oral prednisolone or other oral immunosuppressive drugs (eg, azathioprine, cyclosporine) in the last month. However, patients taking antihistamines were not excluded because it was impossible for the patients to discontinue their urticaria treatment. Other exclusion criteria included CU associated with any systemic disease, thyroid disease, diabetes mellitus, autoimmune disorder, or atopic dermatitis. Pregnant and lactating women were not included in this study.
All new adult CU patients (ie, disease duration >6 weeks) were worked up using the routine diagnostic tests that are typically performed for any new CU patient, including complete blood cell count with differential, erythrocyte sedimentation rate, liver function tests, urine analysis, and hepatitis B and C screenings. Further diagnostic tests also were carried out when appropriate according to the patient’s history and physical examination, including levels of urea, electrolytes, thyrotropin, thyroid antibodies (antithyroglobulin and antimicrosomal), and antinuclear antibodies, as well as a Helicobacter pylori test.
All of the patients enrolled in the study were evaluated by skin prick testing to establish the link between CU and its cause. Patch testing was performed in patients who were negative on skin prick testing.
Skin Prick Testing
All patients were advised to temporarily discontinue the use of antihistamines and corticosteroids 5 to 6 days prior to testing. To assess the presence of allergen-specific IgE antibodies, skin prick testing is preferred because it is more sensitive and specific, is simple to use, is inexpensive, and is not associated with any complications.9
Patch Testing
Patch tests were carried out using a ready-to-use epicutaneous patch test system for the diagnosis of allergic contact dermatitis (ACD).10 A European standard series was used with the addition of 4 allergens of local relevance: black seed oil, local perfume mix, henna, and myrrh (a topical herbal medicine used to promote healing). Patients with a negative skin prick test who had a positive patch test were enrolled in an allergen-avoidance program to avoid the offending allergen for 8 weeks.
Assessment of Improvement
Assessment of urticaria severity using the Chronic Urticaria Severity Score (CUSS), a simple semiquantitative assessment of disease activity, was calculated as the sum of the number of wheals and the degree of itch severity graded from 0 (none) to 3 (severe), according to the guidelines established by the Dermatology Section of the European Academy of Allergology and Clinical Immunology, the Global Allergy and Asthma European Network, the European Dermatology Forum, and the World Allergy Organization.11 The avoidance group of patients was assessed at baseline and after 1 month to evaluate changes in their CUSS after allergen avoidance for 8 weeks.
Statistical Analysis
All of the statistical analyses were carried out using SPSS software version 16. Results were presented as the median with the range or the mean (SD). Descriptive statistics were used to describe the demographic data. The comparability of demographic and baseline characteristics among CIU patients was assessed using the Student t test, and P<.05 was considered statistically significant.