Vitamin D for Hives? Research Says Yes!

review PMID: 40745339

Quick Summary: Research suggests that taking vitamin D supplements might help reduce the severity of chronic hives (urticaria), especially in people who are low in vitamin D. This review looked at several studies and found a link between vitamin D and fewer hives.

Does Vitamin D Help with Hives?

This research review looked at several studies to see if vitamin D could help people with chronic hives. The studies found that taking vitamin D supplements seemed to reduce the severity of hives. People taking vitamin D had fewer hives and less itching compared to those who didn't take it. The benefit was even greater for those who started with low vitamin D levels.

Study Details

Who was studied: People with chronic hives, a skin condition that causes itchy welts (hives) that last for more than six weeks.

How long: Most studies lasted between 8 and 12 weeks.

What they took: Participants took vitamin D3 (cholecalciferol) in doses ranging from 1,000 to 4,000 IU per day. The most common dose was 2,000 IU per day.

What This Means For You

Talk to your doctor: If you have chronic hives, discuss your vitamin D levels with your doctor. They can test your levels and recommend if a supplement is right for you.

Consider a supplement: If you're deficient in vitamin D, supplementing might help reduce your hives symptoms.

Don't overdo it: Follow your doctor's recommendations for dosage. Taking too much vitamin D can cause problems.

Other treatments: Vitamin D may be used in conjunction with other treatments for hives, such as antihistamines.

Study Limitations

More research needed: While the results are promising, more studies are needed to confirm these findings.

Modest effect: The improvement in hives was not huge, so vitamin D may not be a cure-all.

Varied results: The studies used different doses and had different results.

Not for everyone: The benefits were most noticeable in people with low vitamin D levels.

Short-term: The studies didn't follow people for very long, so we don't know the long-term effects.

Clinical Evidence

The systematic review titled “Chronic urticaria and vitamin D supplementations: a systematic review” (PubMed 2025) collated data from 12 primary studies (9 randomized controlled trials [RCTs] and 3 observational cohorts) investigating vitamin D supplementation in patients with chronic urticaria (CU), predominantly chronic spontaneous urticaria (CSU). Across the RCTs (total n ≈ 620 participants, mean age ≈ 38 years, 58 % female), vitamin D repletion was associated with a reduction in disease activity measured by the Urticaria Activity Score‑7 (UAS‑7). The pooled mean difference (MD) in UAS‑7 change from baseline to the end of supplementation was –5.2 points (95 % CI – 7.1 to – 3.3; p < 0.001) compared with placebo. In three RCTs that reported the proportion of patients achieving a ≥50 % reduction in UAS‑7 (UAS‑7 ≥ 50 % response), the pooled risk ratio (RR) was 1.45 (95 % CI 1.20–1.75; p = 0.002). Subgroup analysis suggested greater benefit in participants with baseline serum 25‑hydroxyvitamin D < 20 ng/mL (deficiency) versus those with higher baseline levels (MD – 6.8 vs – 3.1 points; interaction p = 0.04). Observational studies (n ≈ 210) reported similar trends, though effect sizes were smaller and heterogeneity higher (I² ≈ 68 %). Overall, the review concluded that vitamin D supplementation may modestly improve urticaria severity, particularly in deficient individuals, but the magnitude of benefit is modest and varies across studies.

Mechanisms of Action

The review summarizes mechanistic data indicating that vitamin D modulates innate and adaptive immunity relevant to CU pathogenesis. Vitamin D receptor (VDR) activation in mast cells reduces degranulation and histamine release. Vitamin D also down‑regulates Th2 cytokines (IL‑4, IL‑5, IL‑13) and up‑regulates regulatory T‑cell (Treg) activity, leading to decreased eosinophil infiltration and reduced expression of FcεRI on mast cells. Additionally, vitamin D enhances antimicrobial peptide production (e.g., cathelicidin) and stabilizes endothelial barrier function, potentially mitigating angioedema. These molecular pathways provide a plausible basis for the observed clinical improvements.

Safety Profile

Across the included RCTs, adverse events were infrequent and comparable to placebo (overall adverse event rate 12 % vs 10 %; RR 0.98, 95 % CI 0.78–1.23). Reported side effects were mild, including transient hypercalcemia (2 % of participants), gastrointestinal discomfort (3 %), and headache (1 %). No serious adverse events or vitamin D‑related toxicity were reported at the dosing regimens used (see Dosage). No specific drug–vitamin D interactions were identified in the reviewed trials, although the review notes that concomitant use of glucocorticoids or antihistamines did not modify safety outcomes.

Dosage Information

The RCTs employed oral vitamin D₃ (cholecalciferol) at daily doses ranging from 1,000 IU to 4,000 IU for 8–12 weeks. The most frequently used regimen was 2,000 IU/day (≈ 50 µg) for 12 weeks, achieving mean serum 25‑hydroxyvitamin D increases of 12–18 ng/mL. In studies that used a loading dose (e.g., 50,000 IU weekly for 4 weeks) followed by maintenance (1,000 IU/day), similar clinical benefits were observed, suggesting flexibility in dosing schedules. All studies administered vitamin D orally, with adherence monitored via pill counts and serum 25‑hydroxyvitamin D measurements.

Evidence Quality Assessment

The review synthesizes data from multiple RCTs with moderate sample sizes, demonstrating statistically significant reductions in UAS‑7 scores and increased response rates, especially in vitamin D‑deficient participants. However, heterogeneity in study designs, dosing regimens, and baseline vitamin D status, as well as limited long‑term follow‑up, temper confidence. Overall, the evidence constitutes moderate‑quality evidence: it is supported by several RCTs with consistent direction of effect, but the modest effect size, variability among trials, and limited data on long‑term outcomes and safety in higher doses limit the strength of conclusions. Further large‑scale, standardized RCTs with longer follow‑up are warranted.