NCT05810233

Effect of Vitamin C on Allergy Skin Test

The Effect of Vitamin C on the Skin Prick Test Wheal Reaction

• Status: Unknown
• Phase: N/A
• Study type: Interventional
• Enrollment: 90 (estimated)
• Sponsor: National University of Malaysia · Academic / Other
• Sex: All
• Age: 18 Years – 40 Years
• Healthy volunteers: Not accepted

Summary

This study will assess the effect of taking vitamin C on allergy skin test.

Detailed description

Allergic rhinitis (AR) is an Immunoglobulin E (IgE) mediated inflammation of the nasal cavity. House dust mite is the most common causative allergen. The skin prick test is the preferred method to confirm allergy. This test is interpreted by measuring the skin wheal reaction in response to allergen application and histamine. Prior studies have shown that Vitamin C may have antihistamine effect that may reduce the wheal reaction in skin prick test thus cause difficulties to interpret the results. Current guidelines do not recommend cessation of vitamin C prior to skin prick test. This will require further study in order to further understand the effect of vitamin C in commercially available dose on the skin prick test wheal reaction. In this randomized placebo controlled trial, consecutive participant visiting the ENT clinic with allergic rhinitis and prior positive skin prick test towards dust mite will be screened for inclusion and exclusion criteria. Participants will either receive vitamin C 1000mg daily for 7 days or placebo. The skin prick test will be performed after one week of intervention and the area of the wheal reaction area (mm2) and longest diameter (mm) recorded. This will be compared between the two groups. The expected outcome is that participants with oral supplementation of vitamin C will have reduced SPT wheal reaction compared to placebo group.

Conditions

• Rhinitis, Allergic
• Allergy

Interventions

Type	Name	Description
DIETARY_SUPPLEMENT	Ascorbic acid 1000mg	Health supplement
OTHER	Placebo	Glucose chewable tablet without any ascorbic acid

Timeline

• Start date: 2023-07-15
• Primary completion: 2023-09-30
• Completion: 2024-01-30
• First posted: 2023-04-12
• Last updated: 2023-08-30

Locations

1 site across 1 country: Malaysia