7 days ago
Gut Health in Rosacea: Diet, Probiotics, and the Microbiome
Growing evidence suggested that the skin and gut may be more closely linked than once thought — especially in chronic inflammatory conditions like rosacea. In a comprehensive review recently published in Biomolecules , Marco Manfredini, MD, from the Department of Dermatology at the University of Modena and Reggio Emilia, Modena, Italy, and colleagues explored the evolving science around how diet, gut microbiota, and probiotics may influence rosacea pathogenesis and symptom severity.
While more clinical studies are needed, the review highlighted new pathways linking gastrointestinal dysbiosis to cutaneous inflammation. The authors proposed that specific dietary modifications and the use of probiotics could support traditional treatment approaches for certain patients.
Pathogenesis of Rosacea: A Multifactorial Inflammatory Process
Rosacea arises from a complex interplay of multiple contributing factors. 'The pathogenesis of rosacea continues to be a subject of investigation,' the authors wrote, involving 'dysregulation of the innate immune response and neuropeptide activity, microbial involvement, environmental factors, dietary triggers, and skin barrier dysfunction.'
Central to these mechanisms is the innate immune system. In rosacea, elevated levels of kallikrein-5 trigger excessive processing of antimicrobial peptides into proinflammatory fragments such as LL-37. These fragments promote oxidative stress, cytokine release, and blood vessel changes, contributing to the inflammation and vascular symptoms seen in the disease, according to the authors.
Neurovascular dysregulation is also a hallmark of the disease. The authors noted, 'activation of TRPV1 [Transient Receptor Potential Cation Channel Subfamily V Member 1] and related channels by environmental triggers like heat and UV [ultraviolet] radiation exacerbate flushing and erythema by promoting vasodilation and neurogenic inflammation.' These channels are hypersensitive in patients with rosacea, contributing to enhanced symptom severity.
While the skin microbiome — particularly Demodex folliculorum and its associated Bacillus oleronius — has long been considered a contributing factor, recent attention has turned to the gut.
'Emerging evidence suggests that while microorganisms may not be central causative factors… alterations in the skin microbiome across multiple rosacea subtypes may act as trigger factors or potentiate inflammation,' the review authors wrote. 'Gastrointestinal dysbiosis, including conditions such as Helicobacter pylori infection and small intestinal bacterial overgrowth (SIBO),' they noted, 'has been hypothesized as a potential contributor to rosacea development.'
Gut Dysbiosis and the Skin: The Available Evidence
The concept of a gut–skin axis describes the bidirectional relationship between intestinal microbiota and skin inflammation. In rosacea, this relationship is supported by associations with conditions like SIBO, H pylori infection, and inflammatory bowel diseases, as highlighted in the Manfredini review.
Asked to comment on this emerging topic, Rajani Katta, MD, clinical professor of dermatology at the McGovern Medical School, University of Texas, Houston, noted, 'We have strong evidence linking gut dysbiosis to rosacea, but it is important to note that this applies only to certain patients. In other words, only a subset of patients with rosacea seems to have gut dysbiosis, and in those patients, there appears to be a link.'
Rajani Katta, MD
Katta added that the most compelling mechanisms relate to inflammation. 'Patients with SIBO may have higher levels of inflammatory mediators, such as tumor necrosis factor alpha. In other studies, gut dysbiosis can lead to the activation of specific inflammatory pathways like the kallikrein-kinin pathway. Activation of these pathways has multiple downstream effects, which may ultimately increase neurogenic inflammation in the skin.'
The review by Manfredini and colleagues supported these theories, citing studies that show improvement in rosacea symptoms following SIBO eradication, although the benefit of H pylori treatment is less clear.
'The association between Helicobacter pylori infection and rosacea remains complex and influenced by several confounding factors,' the authors wrote. 'The antibiotic treatment required for H pylori eradication represents an important confounding factor.' The authors caution that without large-scale prospective studies examining the gut microbiome before and after intervention, firm conclusions about causality remain elusive.
Dietary Triggers: What the Evidence Supports
Dietary factors may influence rosacea by promoting vasodilation, activating sensory receptors, or altering the gut microbiome. Yet, data on specific triggers remain mixed, according to the authors.
Asked to comment on dietary triggers in rosacea, Lauren Kole, MD, associate professor of dermatology at the University of Alabama at Birmingham, said that 'the best data for dietary triggers for rosacea are for alcohol and hot beverages. Alcohol may induce peripheral vasodilation, promote inflammation, modulate the immune system, and may trigger histamine release. Hot beverages may cause direct vasodilation and trigger other pathways that lead to flushing, stinging, and sensitive skin.'
Katta also noted that alcohol and hot beverages 'are common triggers, likely because they lead to vasodilation, which causes flushing.' She also highlighted spicy foods as a culprit. 'Foods that contain capsaicin may result in vasodilation and thus flare rosacea, so avoiding spicy foods may be helpful.' Another category included foods that contain cinnamaldehyde — a compound found in cinnamon, tomatoes, and citrus —which may trigger flushing in sensitive individuals, according to Katta.
Katta recommended a practical approach for patients. 'For most patients, a 6-week trial of eliminating the most commonly reported food triggers in rosacea is a good first step… I tell patients that it can take 6 weeks of avoiding these foods to see if it will be helpful, and I recommend a food diary.'
Interestingly, certain foods may offer benefits. Dairy products have been associated with reduced rosacea severity in some populations, potentially because of their anti-inflammatory effects. High-fiber diets may support gut microbial diversity and caffeine — despite its reputation — has been inversely associated with rosacea in large observational studies, cited in the Manfredini review.
Probiotics: Potential but Preliminary
Probiotics are another area of growing interest. These live microorganisms may influence rosacea by rebalancing the gut microbiome, reducing inflammatory cytokine production, and enhancing skin barrier function, according to the authors.
'Dietary probiotics may help normalize skin dysbiosis in rosacea and may limit substance P-induced skin inflammation,' said Kole. She referenced a study that found improved skin barrier function and reduced sensitivity with oral probiotic use alongside doxycycline therapy.
Katta said that she has not used probiotics for rosacea in her practice. 'Preliminary results appear intriguing, but there are still many questions about the optimal strain of probiotics as well as dose and duration,' she told Medscape Medical News . She added that the current evidence is 'too preliminary to recommend specific strains or delivery routes, although some have shown benefit,' referencing studies on strains of Bifidobacterium , Lactobacillus , and Escherichia coli Nissle included in the Manfredini review.
Topical formulations are also being explored with promising results, and a product containing Vitreoscilla filiformis has shown reductions in facial erythema and Demodex density while improving transepidermal water loss, according to the review's authors.
However, mirroring Katta's sentiment, the authors concluded that 'despite promising results, the evidence supporting the use of probiotics in the treatment of rosacea remains relatively limited. Further clinical trials are necessary to evaluate and compare the effectiveness of various probiotic strains and different methods of delivery, such as oral ingestion and topical use.'
Looking Ahead: Clinical Considerations and Research Needs
While the current research is promising, more rigorous studies are needed. 'One of the research areas that I'd love to see more of,' Katta said, 'is measuring rates of gut dysbiosis in patients with rosacea, with prospective studies examining gut microbiome composition before and after treatment, and how that correlates to rosacea severity.'
For now, clinicians may consider an individualized approach, she said, and asking about gastrointestinal symptoms, evaluating for common dietary triggers, and discussing a food elimination trial can be helpful strategies. Although formal probiotic guidelines for rosacea are lacking, some patients may benefit from a monitored trial of supplementation — particularly if they also have gut-related complaints, she added.
'There are many gaps in our understanding of the gut–skin axis,' Katta emphasized. 'But it's an exciting area of dermatologic research.'
