Skin Prick Test Positivity in Chronic Urticaria

Area of Science:

• Dermatology
• Allergology
• Clinical Immunology

Background:

• Chronic urticaria (CU) diagnosis often involves identifying specific allergens.
• Skin prick testing (SPT) is a key method for allergen identification in CU.
• This study investigated SPT positivity in CU patients at a tertiary care center in Nepal.

Purpose of the Study:

• To determine the prevalence of allergen sensitization in patients diagnosed with chronic urticaria.
• To identify common allergens triggering chronic urticaria in the Nepalese population.
• To evaluate the utility of skin prick testing in the diagnostic workup of chronic urticaria.

Main Methods:

• A cross-sectional study was conducted involving 62 patients aged over 16 years with chronic urticaria.
• Patients underwent skin prick testing with 21 allergens, including environmental dusts, insects, fungi, and food allergens.
• Standard protocols, including negative (saline) and positive (histamine) controls, were followed as per Global Allergy and Asthma European Network guidelines.

Main Results:

• Overall, 71% of chronic urticaria patients showed positive reactions to at least one allergen.
• The most frequent sensitizing allergens were Dermatophagoides farinae (50%), cotton dust (17.7%), and mosquito (16%).
• A majority of sensitized patients (55%) reacted to more than one allergen, indicating polysensitization.

Conclusions:

• A substantial percentage of chronic urticaria cases in this population are linked to sensitization to various allergens.
• Skin prick testing is a valuable and effective diagnostic tool for identifying allergens in patients with chronic urticaria in Nepal.
• These findings support the routine use of SPT in the management of chronic urticaria to guide allergen avoidance and treatment strategies.