Salt and Skin: Exploring the Connection Between Diet and Eczema

A new research study highlighted a significant link between high salt intake and increased eczema prevalence, urging a revaluation of dietary habits in eczema management.

A Global Health Concern

Eczema, or atopic dermatitis, is a chronic, relapsing, inflammatory skin condition characterised by the development of intense eczematous lesions and severe itching. This condition results in significant discomfort and distress to sufferers. Typically, eczema develops in childhood and in approximately 80% of children with eczema, the disease persists into adulthood.

In higher-income countries, rapid urbanisation has led to the disease affecting around 20% of children and up to 10% of adults. Globally, eczema impacts around 194.4 million people. Alarmingly, the prevalence is increasing worldwide, including in large parts of Asia. In Southeast Asia alone, between 3.7- 13.5% of children aged 6-7 years old suffer from eczema. It becomes crucial to understand the factors contributing to eczema and how to manage it effectively.

One such factor contributing to eczema is the association with salt. In this article, we review the latest research findings. Additionally, we discuss advice and methods of eczema management that healthcare professionals can utilise in their practice to help improve the quality of life for patients suffering from this debilitating condition.

Why is Eczema Prevalence Increasing?

There is notably a higher eczema prevalence in Asia compared to the rest of the world. Within Asia, there is almost unanimous agreement that the increasing prevalence of eczema can be largely attributed to environmental and socioeconomic factors, including rapid urbanisation, increased family income, adoption of a more Westernised lifestyle, increased exposure to allergens, climate change, frequent bathing and use of soap, change of diet and clothing choice. In addition, improved accuracy of diagnosis in some areas may also partially contribute to the increased prevalence.

The Role of Diet in Eczema Development

One key component in the development of eczema is inflammation. Therefore, foods that result in activation of the immune system can increase risk of developing eczema. For example, diets high in sugar and refined carbohydrates can result in elevated insulin levels which promotes inflammation. Processed foods that often contain artificial additives, preservatives, and trans fats, which can promote inflammation can also potentially exacerbate eczema symptoms. Processed foods are also often associated with increased sodium/salt.

Salt Intake Associated with Eczema

In a recently published study in JAMA Dermatology, the scientists sought to measure how much greater consumption of dietary sodium is linked with eczema. Researchers analysed 24-hour urine sodium excretion from single-spot urine samples collected from over 215,000 participants from the UK Biobank. Among these, close to 11,000 were previously diagnosed with eczema. These are the findings:

• With every 1g increase in sodium excretion, there was an 11% increase in the odds of having eczema.
• Also, the odds of active eczema are increased by 16%, and the odds of having more severe symptoms are elevated by 11%.
• Validating in a US cohort of over 13,000 participants using dietary questionnaires, they found that 1g of dietary sodium intake was linked to 22% higher risk of current eczema.
• Among participants with less than the NHS-recommended level of sodium intake, there was no increased eczema risk.
• Females had higher odds of eczema associated with higher levels of urine sodium.

Strategies for Managing Eczema

With the rise in prevalence of the condition and armed with these new research findings, healthcare professionals can enhance their advice to patients:

• Dietary Changes

Educate patients about the new research between high salt intake and the exacerbation of their symptoms. Advise patients to monitor and reduce their salt intake, particularly from processed foods. While more studies are necessary to fully understand the impact of sodium, the benefits to advising patients to reduce salt intake are clear. Since the average person in developed countries consumes more than the recommended amount of salt, reducing salt intake not only potentially alleviates the symptoms, it can lower the risk for cardiovascular diseases.

• Lifestyle Modifications

Educate patients on how stress management, regular exercise, and good sleep hygiene can help manage eczema. Stress can trigger and worsen flare-ups so incorporating mindfulness, yoga, or other relaxation techniques can help. Regular physical activity reduces inflammation and boosts immunity which is also beneficial for eczema. However, excessive perspiration can irritate and trigger a flare-up. Keeping a consistent sleep schedule and wearing breathable and soft fabrics to bed can reduce discomfort, stress, and itching.

• Supplements

Some studies suggest Vitamin D, fish oil, zinc, selenium, prebiotics and probiotics, melatonin, turmeric, and primrose oil may reduce the severity of eczema. However, more research is required to substantiate these claims. Healthcare professionals should encourage patients to keep them informed if they decide to supplement. This will help prevent any potential harmful drug interactions. It is also crucial that patients note that the supplements may not work for everyone.

While dietary and lifestyle modifications form the cornerstone of management, they often need to be complemented with appropriate medical treatments. These include:

• Topical Treatments: Emollients and topical corticosteroids remain the first line of treatment for atopic dermatitis. Other topical treatments also include calcineurin inhibitors (tacrolimus (Protopic) and pimecrolimus (Elidel)) and PDE4 inhibitors (crisaborole (Eurcrisa)) to control inflammation, and topical antihistamines to relieve itching.
• Non-Topical Treatments: If a patient’s symptoms are severe or not responding to first-line treatments, doctors can discuss the option of non-topical treatments. They include immunosuppressants, janus kinase inhibitors, and biologic drugs such as Nemolizumab which is administered through subcutaneous injection and has recently obtained approval in Singapore to treat moderate-to-severe eczema.

While there is not a one-size-fits-all solution, the treatments and lifestyle modifications should be tailored to the individual patient’s needs and circumstances. Equally important is the patient’s understanding of their prescribed medication. They should be informed about what the drug is, how it works, its effectiveness, and potential side effects.

Conclusion

As Asia experiences rapid urbanisation and shifts towards processed foods and takeout due to busy lifestyles, the rising prevalence is emerging as a significant health concern. Salt intake has increased, and a recent study highlights the severe impact of high salt intake on the development of eczema. As healthcare professionals refine management strategies- from dietary modifications to advanced pharmacological treatments, with evidence from new research, the global approach to eczema continues to evolve, emphasising the need for ongoing research and comprehensive patient education to improve outcomes in this condition.

References

1. Tsai, T.-F., Rajagopalan, M., Chu, C.-Y., Encarnacion, L., Gerber, R. A., Santos-Estrella, P., Llamado, L. J. Q., & Tallman, A. M. (2019). Burden of atopic dermatitis in Asia. The Journal of Dermatology, 46(10). https://doi.org/10.1111/1346-8138.15048
2. Kash, S. (2023, March 28). Exposing Eczema: Why is it so Common in Asia? Medical Channel Asia. https://medicalchannelasia.com/why-is-eczema-so-common-in-asia/
3. Chiang, B. M., Ye, M., Chattopadhyay, A., Halezeroglu, Y., Van Blarigan, E. L., & Abuabara, K. (2024). Sodium Intake and Atopic Dermatitis. JAMA Dermatology. https://doi.org/10.1001/jamadermatol.2024.1544
4. Eczema Management. National Eczema Association. https://nationaleczema.org/eczema-management/
5. Ng, G. (2024, May 9). Galderma Secures Approval for Nemolizumab in Prurigo Nodularis and Atopic Dermatitis in Four Countries. Medical Channel Asia. https://medicalchannelasia.com/galderma-secures-approval-for-nemolizumab-in-prurigo-nodularis-and-atopic-dermatitis-in-four-countries/
6. Available Eczema Treatment. National Eczema Association. https://nationaleczema.org/eczema/treatment/