Patients with chronic idiopathic urticaria (CIU) or chronic spontaneous urticaria (CSU) may ask whether changing what they eat can help control their symptoms. A recent scoping review published in Cureus suggests the answer may be yes for some patients, although the evidence is not yet strong enough to recommend a specific diet for everyone.1
Investigators reviewed 8 studies published from 2015 through 2025 examining diet and CIU/CSU. Six reported improvements in disease activity or quality of life, or favorable associations between dietary factors and clinical outcomes. Low-histamine, pseudoallergen-free, and Mediterranean dietary approaches were among those associated with potential benefits.1
CIU vs CSU: What’s the Difference?
Although the review uses the term CIU, clinicians may be more familiar with CSU. The terms are often used interchangeably and both describe recurrent wheals, angioedema, or both lasting longer than 6 weeks without an identifiable external trigger.1
The difference is primarily one of terminology and emphasis. “Idiopathic” emphasizes the absence of an identifiable cause, whereas “spontaneous” describes symptoms that occur without a specific external stimulus. The review authors used both CIU and CSU to remain consistent with terminology across the included literature.1
For NPs and PAs, the important point is that the dietary evidence summarized in the review applies to this same broader patient population.
Which Diets Showed Potential Benefit?
Several approaches were associated with improvements, although response varied considerably between patients.
In a study of 56 patients with CSU and gastrointestinal symptoms, following a low-histamine diet for at least 3 weeks reduced mean Urticaria Activity Score over 4 days (UAS4) from 9.05 to 4.23 (P = .004). Overall, 75% of participants were reported to benefit from the diet.1,3
Another study followed 22 adults with chronic urticaria for 4 weeks on a histamine-free diet. Mean Urticaria Activity Score over 7 days (UAS7) decreased from 10.3 ± 9.2 to 4.1 ± 4.1 (P = .006), and plasma histamine levels also decreased significantly.1
Pseudoallergen restriction showed potential benefit as well. Among 23 patients with poorly controlled CSU who followed a pseudoallergen-free diet for 3 weeks, 26.1% achieved a strong response and another 26.1% achieved a partial response. Antihistamine use decreased in 43.5% of participants.1
What About the Mediterranean Diet?
Not every potentially beneficial approach involved eliminating foods.
In a study comparing 100 patients with CSU with 100 matched healthy controls, greater adherence to the Mediterranean diet was associated with lower UAS7 scores and higher Urticaria Control Test scores.2
This finding is particularly interesting because the Mediterranean diet differs considerably from restrictive low-histamine diets. Foods that may be included in a Mediterranean diet, including certain fruits, vegetables, aged cheeses, and wine, may be restricted in low-histamine or pseudoallergen-free approaches.1
The differences between these diets also make it difficult to identify which individual foods or nutrients may be responsible for the observed associations.
Frequently Asked Questions
Does diet affect chronic idiopathic urticaria?
Emerging evidence suggests dietary modification may improve disease activity or quality of life in some patients with CIU/CSU. Six of the 8 studies included in the scoping review reported improvements or favorable associations, but current evidence is insufficient to establish standardized dietary recommendations.1
Which diets showed benefit for chronic urticaria?
Mediterranean, low-histamine, histamine-free, and pseudoallergen-free dietary approaches were associated with improved disease control, disease activity, or quality of life in at least 1 included study.1
What are the main limitations of the current evidence on diet and CIU?
Studies generally had small sample sizes and short intervention periods, with limited mechanistic or provocation testing. None of the included studies were conducted in the United States, and potential confounding factors were inconsistently controlled.1
Not Every Patient Responded
The review also highlights why clinicians should be cautious about attributing CSU symptoms to dietary histamine alone.
In a study of 157 patients with moderate-to-severe CSU, 46% experienced at least a 7-point reduction in UAS7 after following a histamine-free, low-pseudoallergen diet for 31 days. However, only 17% subsequently developed a positive wheal response during oral histamine provocation testing.1
Just 2 of 157 patients had agreement across all 3 measures: a history suggestive of histamine intolerance, improvement with the diet, and a positive provocation test.1
The findings suggest that although dietary restriction may help some patients, improvement cannot necessarily be attributed to histamine avoidance itself.
What Should NPs and PAs Tell Patients?
The evidence supports an individualized conversation rather than recommending that every patient with CIU/CSU start an elimination diet.
Current management remains centered on established pharmacologic treatment, beginning with second-generation H1-antihistamines and escalating treatment when disease remains inadequately controlled. Dietary modification should therefore be viewed as a potential adjunct, rather than a replacement for conventional treatment.1
Clinicians should also consider the burden associated with restrictive diets. The included interventions were generally short, and the review does not establish whether their benefits persist with long-term use.
More Research Is Needed Before Routine Recommendations
The review also identified potential associations between CIU/CSU and micronutrient or inflammatory markers, although the findings do not establish
Specific Foods and BMI Also Linked to CSU
Only 8 studies met the review's final inclusion criteria, and several enrolled fewer than 100 participants. Most dietary interventions lasted approximately 3 to 4 weeks, leaving questions about long-term effectiveness and adherence unanswered.1
None of the studies were conducted in the United States, and populations were predominantly female. Potential confounding factors such as psychological stress, physical activity, supplements, and medication use were also inconsistently controlled.1
Only 4 studies examined biological or inflammatory markers, and just 1 incorporated oral histamine provocation testing. As a result, researchers still do not fully understand why dietary modification might improve symptoms—or which patients are most likely to respond.1
For now, the review authors suggest clinicians may consider individualized dietary counseling for selected patients while balancing potential symptom improvement against the challenges of dietary restriction.1
References
- D'Alessio O, Huber E, LeMaire J, Camacho B, Rodriguez J. The role of diet in the management of chronic idiopathic urticaria: a scoping review. Cureus. 2026;18(8):e115321. doi:10.7759/cureus.115321
- Ayvaz HH, Kuyumcu A. Effect of the Mediterranean diet in patients with chronic spontaneous urticaria. Rev Assoc Med Bras (1992). 2021;67:675-680. doi:10.1590/1806-9282.20201076
- Wagner N, Dirk D, Peveling-Oberhag A, Reese I, Rady-Pizarro U, Mitzel H, Staubach P. A popular myth: low-histamine diet improves chronic spontaneous urticaria, fact or fiction? J Eur Acad Dermatol Venereol. 2017;31:650-655. doi:10.1111/jdv.13966
