In a first of its kind study, researchers at the Nebraska Medical Center looked at whether or not vitamin D as an add-on therapy to a traditional treatment plan helped reduce the number and severity of hives in those with chronic urticaria.
Chronic urticaria (CU) is a condition where you develop hives on a daily basis for longer than six weeks. Hives are itchy, red skin eruptions that are not contagious. They often occur in response to environmental allergens, foods, or medications. In many instances the cause is not known. Current estimates suggest that 10-20% of the population will experience hives at some point, and 1-3% will develop CU.
Previous research has linked vitamin D deficiency to asthma and eczema. Because these same researchers had previously shown patients with CU were more deficient in vitamin D compared to those with allergic rhinitis, they designed this study to see if supplemental vitamin D could help with the symptoms of CU.
The researchers recruited 42 patients with CU and randomized them into two vitamin D supplement groups:
- 21 into the low dose group, 600 IU/day
- 21 into the high dose group, 4,000 IU/day
Patients were eligible to participate in the study if they had been experiencing hives on a daily or near daily basis for the past six weeks.
In addition to vitamin D, all patients were provided with 10 mg of ceterizine twice daily, 150 mg of ranitidine twice daily, and 10 mg of montelukast daily, all drugs for the treatment of CU. They were instructed to take their vitamin D and medications for twelve weeks.
25(OH)D levels were measured at baseline, six weeks, and completion of the study. A Urticaria Symptom Severity (USS) score assessment was administered at the same time to determine how severe CU symptoms were.
One week into the study, there was a 33% reduction in CU symptoms in both groups, which was credited to the drug therapy. However, at completion of the study, only the high vitamin D group showed a statistically significant 40% reduction in total USS score as compared to baseline.
Those taking the high dose vitamin D also reported a significant reduction in body distribution of hives on an average day and a worst day as well as less days with hives. Those taking high dose D showed a decreased USS score as compared to the low dose D group at the end of the study, but this result was not statistically significant.
The 25(OH)D level of the low dose group at baseline was 37.1 ng/mL and was 35.8 ng/mL upon study completion. In contrast, the 25(OH)D level of the high dose group was 28.8 ng/mL at baseline and 56 ng/mL upon study completion. While there was technically no placebo group, the low dose group functioned as a placebo group because there was no statistically significant change in their blood levels of vitamin D.
The researchers had predicted vitamin D supplementation would reduce the need for medication, but this was not the case. Still, the high dose vitamin D group showed statistically significant results for reduced number and distribution of hives as well as days with hives.
The researchers proposed that vitamin D’s beneficial effects on inflammation and immune regulation were likely responsible for the results of this study. The researchers recommended that 4,000 IU of vitamin D per day be given to CU patients as a safe add-on therapy to traditional medications. It should not be used in place of your prescribed medications.