Effect of Vitamin C on Allergy Skin Test
Study Details
Study Description
Brief Summary
This study will assess the effect of taking vitamin C on allergy skin test.
Condition or Disease | Intervention/Treatment | Phase |
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N/A |
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.
Study Design
Arms and Interventions
Arm | Intervention/Treatment |
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Experimental: Vitamin C Commercially available Tablet Vitamin C 1000mg per day for 7 days |
Dietary Supplement: Ascorbic acid 1000mg
Health supplement
Other Names:
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Placebo Comparator: Placebo Sucrose tablets 1 per day |
Dietary Supplement: Ascorbic acid 1000mg
Health supplement
Other Names:
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Outcome Measures
Primary Outcome Measures
- Skin prick test wheal area of vitamin C group compared to placebo [Day 8]
Skin wheal reaction is measured using computer software. Day 8 wheal area of vitamin C group compared to placebo.
Secondary Outcome Measures
- Skin prick test wheal reaction at day 8 of intevention compraed to prior skin prick test done as standard of care [Day 8]
Skin wheal reaction are is measured from prior skin test record (baseline) and at day 8 skin test repeated and measured. Area at day 7 - baseline.
Eligibility Criteria
Criteria
Inclusion Criteria:
- Participants above 18-years old 2) Participants with history at least 2 symptoms of rhinitis triggered by dust 3) Positive SPT to Dermatophagoides pteronyssinus with wheal reaction of at least 5 mm done within the past 1 year.
Exclusion Criteria:
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Prior skin prick test result form do not include a tracing of the wheal reaction.
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Prior skin prick test was not performed in HCTM.
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Participants who are actively smoking or who have smoked cigarette or vape in the past 6 months
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Participants with skin conditions affecting the volar aspects of the arm.
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Participants on beta-blockers
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Participants contraindicated for skin prick test (pregnancy, history of anaphylaxis, poorly controlled asthma)
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Participants on long term supplements (multivitamin, traditional supplement)
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Participants contraindicated for vitamin c (vitamin c allergy, kidney dysfunction, history of kidney or bladder stones, hyperuricemia, thalassemia, G6PD deficiency, sickle cell disease, hamatochromatosis)
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Participants at risk of vitamin C deficiency (hyperthyroidism, elderly, beastfeeding, diarrhoea, restricted diet secondary to inflammatory bowel disease, anorexia or cancer)
Contacts and Locations
Locations
No locations specified.Sponsors and Collaborators
- National University of Malaysia
Investigators
- Principal Investigator: Aneeza K W Hamizan, National University of Malaysia
Study Documents (Full-Text)
None provided.More Information
Publications
- Fortner BR Jr, Danziger RE, Rabinowitz PS, Nelson HS. The effect of ascorbic acid on cutaneous and nasal response to histamine and allergen. J Allergy Clin Immunol. 1982 Jun;69(6):484-8. doi: 10.1016/0091-6749(82)90171-3.
- Skoner DP. Allergic rhinitis: definition, epidemiology, pathophysiology, detection, and diagnosis. J Allergy Clin Immunol. 2001 Jul;108(1 Suppl):S2-8. doi: 10.1067/mai.2001.115569.
- JEP-2023