Add-on therapy with 4,000 International Units (IUs) of vitamin D3 per day could be considered safe and potentially beneficial in patients with chronic hives, the authors reported online February 7 in Annals of Allergy, Asthma & Immunology.
But principal investigator Dr. Jill A. Poole of the University of Nebraska Medical Center in Omaha cautioned by phone with Reuters Health that "urticaria is usually a tough disease to treat; in our study, vitamin D was an add-on therapy, not a cure."
"We studied doses that are readily available over the counter, 600 IU vs 4,000 IU, which is the National Institute of Medicine's upper safe limit for adults, and patients on 4,000 IU had a 40% reduction in their hives symptoms," she said.
"But vitamin D has a long half-life and needs to be given for up to three months to reach a steady state in the body. We didn't see effects until the end of the study at three months," she added.
Building on previous observational studies, Dr. Poole and her colleagues conducted the first randomized controlled trial linking vitamin D with chronic urticaria. To explore whether high-dose vitamin D supplements would decrease the Urticaria Symptom Severity (USS) scores and the medication burden in patients with chronic hives, the research team conducted a prospective, double-blind study of 42 adults at one academic medical center.
The patients had a history of urticaria and/or angioedema daily or almost daily for longer than six weeks, although the mean duration in both groups was over five years.
The researchers excluded patients with pure physical urticaria, angioedema, hypercalcemia, renal insufficiency, primary hyperparathyroidism, sarcoidosis, granulomatous disease, malignancy or who were pregnant or lactating.
All patients were given a standard triple-drug therapy (cetirizine, ranitidine, and montelukast) for the duration of the study.
Additionally, in the high-dose group, 21 patients were randomized to take 4,000 IU of vitamin D3 per day, and in the low-dose group, 21 patients were randomized to take 600 IU of vitamin D3 per day, for 12 weeks.
At enrollment and weeks one, six, and 12, all patients completed the USS and had their allergy medications for chronic hives recorded. At enrollment and weeks six and 12, their blood was tested for 25-hydroxyvitamin D.
The USS is an established questionnaire with 12 questions about hives severity. Scores range from 0 to 93, with higher numbers indicating more severe hives.
At enrollment, the two groups had similar total USS scores, but one week after enrolling and starting the triple-drug therapy, the total USS score decreased 33% in both groups (p=0.001).
Then the groups split: the high-dose group -- but not the low-dose group -- decreased 40% more in its total USS score at 12 weeks, compared with the total USS score at one week after enrollment (p=0.02).
Compared with the low-dose group, the high-dose group trended toward lower total USS scores at week 12 (p=0.052), with significant decreases in body distribution, fewer days with hives, improved pruritus and sleep quality.
Serum 25-hydroxyvitamin D levels increased in the high-dose group, but there was no correlation between 25-hydroxyvitamin D levels and USS scores. Both groups had similar allergy medication use, and there were no adverse events.
Co-author Dr. Whitney S. Goldner, also of the University of Nebraska Medical Center in Omaha, wrote in an email to Reuters Health, "It is known that vitamin D is beneficial for treatment of metabolic bone disease, and it has been suggested that it is helpful in other disease states such as autoimmune or inflammatory conditions, but this prospective study helps add more data to support these previous findings and observations."
"This is a very frustrating disease for patients and they tend to search for answers," said Dr. Poole by phone. "I'm not sure vitamin D is going to be the answer for them, but it's worth a try. People might benefit from it, and what an easy over-the-counter help it would be for the patients, compared with some of the more serious medications that have adverse effects.
SOURCE : http://www.annallergy.org/article/S1081-1206%2814%2900012-X/abstract
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