There is a lot of debate about the causes of eczema such as leaky gut, food allergies, chemical sensitivities and genetic defects. Some research is more 'hypothesis' than fact. Some research sounds great in theory (works great in a test tube) but when you try it on a real person it does not fix their eczema. Some advice is based on one person's experiences with eczema, but may not work for others.
So today I want to share with you the scientific research on salicylate sensitivity which helped me to formulate the eczema diet program for patients at the Eczema Life Clinic in Sydney. I'll also discuss case studies, including my son's recent struggles with salicylate sensitivity and leaky gut.
Salicylate sensitivity facts
Here are the salicylate sensitivity statistics:
- Salicylates trigger hives in 62%^ to 75%* of people who are prone to skin rashes
- Salicylates worsen/trigger eczema in 52% of people with eczema^
- Salicylates worsen/trigger irritable bowel in 69% of people with IBS^
- Salicylates trigger migraines in 62% of people prone to migraines^
- Salicylates trigger behaviour abnormalities (such as ADHD, aggression and anxiety) in 74% of people with behaviour issues^
- Salicylates trigger lethargy and a range of systemic symptoms in 74% of people with systemic symptoms (symptoms affecting the whole body)^
^Loblay and Swain; *Warin and Smith (see full references at end of the article)
What are salicylates?
Salicylates are a natural pesticide/chemical found in some fruits and vegetables, nuts, teas, fruit extracts, wine, herbal medicines, aspirin and spices. Artificial and natural salicylates are also present in many skin creams and perfumes.
Both natural and artificial salicylates, if consumed in large doses, can cause health problems in anyone (for example, aspirin overdose). However, people with salicylate sensitivity react to regular amounts of salicylates that are found in foods. For example they react to coconut, avocado and tomato as they are naturally rich sources of salicylates. Often people don't know what is causing their itchy skin as they eat similar meals every day.
Nightshade plants are particularly high in salicylates (except for peeled white potatoes) so this may be why some eczema sufferers report having adverse reactions to nightshades.
The research on salicylates
According to research by Loblay and Swain from the RPA Hospital Allergy Unit in Sydney, ingesting salicylate-rich foods causes a worsening of eczema symptoms. In fact, salicylate sensitivity (also known as salicylate intolerance), is the most common chemical sensitivity that eczema sufferers present with.
According to Anne Swain from the RPA Hospital Allergy Unit in Sydney, it has been known for more than a century that aspirin ingestion could trigger skin rashes (Hirschberg, 1902).
Several researchers in the 1970s reported that diets designed to exclude foods containing salicylates and/or additives induced prolonged remission of skin rashes in those patients who had shown a positive response to oral challenge with these compounds (Swain, 1988).
Of the studies done on salicylate avoidance, 75% of the patients of researchers Warin and Smith either had cleared skin or considerably improved symptoms after being on a low-salicylate diet for a two-month period.
Symptoms of salicylate sensitivity
- eczema, hives, itchy skin and other skin rashes
- headaches or migraines
- irritable bowel symptoms (wind, diarrhoea and/or constipation)
- stomach bloating and discomfort
- irritability, restlessness
- allergy symptoms (stuffy or runny nose, nasal polyps, frequent throat clearing)
- behaviour problems, poor attention span, ADHD, ADD
- slow to talk and/or slow growth (in infants/children)
- sleep disturbances (difficulty falling asleep, night terrors, frequent night waking, sleep apnoea)
- anxiety, panic attacks
- rapid heart beat and arrhythmias
- tinnitus, hearing loss
- joint pain, arthritis
Note these conditions can be caused by other factors, so speak with your doctor for a formal diagnosis... then investigate salicylate intolerance. We did this with our son who suffered from frequent severe abdominal pains, sleep disturbances and headaches. See salicylate sensitivity - case study, below, for more about his diagnosis and treatment.
Salicylate sensitivity and leaky gut - case study 1
As mentioned, over the past couple of years my son had occasional severe pains in his abdomen. He missed about 24 days of school one term because he was in agony. We saw a gastrointestinal specialist from our local hospital, had x-rays, stool analysis and allergy testing. Everything showed up clear except for partially blocked bowels, caused by constipation.
The constipation medication my son was prescribed worked but it gave him other problems so we switched to using fruit juice instead. This worked well, however it always led to mild angry outbursts. He was still having stomach pains and we worked out it was often triggered by tomato sauce and soy (even though they showed up clear on a skin prick allergy test from the RPA Hospital in Sydney).
My son is a sweet, intelligent child but he was also the child who could not sit still in class, and at the beginning of each year his new teachers would usually commented on this. He occasionally became so anxious he would hide under the bed and hyperventilate, and he often complained of headaches. He was not very chatty and as a small child he would prefer to roar like a dinosaur, rather than talk, especially when he was tired or hungry. All are common salicylate-sensitivity signs (I have highlighted each salicylate-sensitivity symptom in bold).
So after ruling out other more serious factors, we began him on a salicylate sensitivity diet - The Eczema Diet Intensive Care Program and Skin Friend.
As he is obsessed with salicylate-rich fruits, it was difficult to follow at first but we found recipes he loved such as crispy chicken, mashed potato and green beans. A week later I was reading him a book at night and I suddenly noticed that he had been completely still for three whole chapters. Arms by his side, totally still. I was a bit alarmed but remembered we had started the new diet. Usually when I read to him, he is wriggling and a bit distracted.
Other positive behavioural changes we have noticed include excessive chattiness (I keep thinking this is not my child, he is usually not big on communication); no constipation and he doesn't need medications or juice anymore; no headaches, no anxiety attacks and best of all, he can handle conflict much better and he calms down quickly. For example, if he gets into trouble, instead of having a melt-down and refusing to go to school, he will complain (defend himself) then let it go. My jaw drops each time.
Why do plants have salicylates?
Salicyates are made by some plants as a natural pesticide - i.e. for protection from bugs. Salicylates also have preservative properties which reduce food spoilage. Eczema sufferers commonly have adverse reactions to preservatives and pesticides so it's little wonder they can also react to salicylates.
Topical steroid withdrawal and salicylates
Salicylates, once consumed, also dilate the blood vessels. This is why aspirin (a salicylate medication) is prescribed to people with high blood pressure as it dilates the blood vessels (Ying, 2009).
So if you have topical steroid withdrawal syndrome, it makes sense to reduce your intake of salicylates as a part of your treatment. The reasoning is this: topical steroids constrict the blood vessels and after years of use there is a rebound reaction when you stop applying the steroids to your skin: the withdrawal causes your blood vessels to excessively dilate.
Research shows the excess dilation seen in topical steroid withdrawal patients is caused by excess nitric oxide in the blood. This excess blood vessel dilation in topical steroid withdrawal patients is likened to rosacea, according to Indian research. Rosacea is caused by an excessive widening of the blood vessels, where the excess blood flow causes the skin to appear red, hot and inflamed (much like TSW/red skin syndrome). Rosacea can become permanent if not treated with a low histamine/low salicylate diet and exercise. However, topical steroid withdrawal symptoms do reverse after a period of time where topical steroid are excluded.
So if you have topical steroid withdrawal or rosacea I recommend reducing your intake of salicylates and amines/histamines to prevent further excess blood vessel dilation.
Amine-rich foods which dilate the blood vessels include chocolate, cheese, wine, fish oils, and fermented foods such as probiotics and yoghurt. This is why chocolate can trigger headaches, it dilates the blood vessels in the brain.
How many people are salicylate intolerant?
Most people with salicylate intolerance have no idea they are sensitive to this hidden chemical. They instead report leaky gut, allergies and skin symptoms and look to suppress the symptoms as quickly as possible. However, these symptoms often point to salicylate sensitivity and/or multiple chemical sensitivity, so any quick fix they try will not address the underlying cause and prevent the problem long-term. The reasoning is this: salicylates damage the gut lining, especially in sensitive people, and this damage can lead to allergies and food intolerances.
For example, the research on aspirin shows it frequently triggers gastrointestinal bleeding as it causes tiny holes in the gut lining. If you are sensitive to salicylates, you can end up with similar gastrointestinal damage from consuming the salicylates found in regular foods.
What is leaky gut? Well, the official medical term is 'intestinal permeability' and the symptoms include bloating, gas, cramps, pains and food sensitivities. Your gut naturally allows very small particles to pass through its walls so you can absorb micronutrients such as vitamins and minerals for good health.
When intestinal permeability occurs the tight junctions in the gut lining are damaged and this allows larger particle to enter the bloodstream. As far as medical research goes, it's still classed in the "unsure it exists" box. However, people with leaky gut symptoms know it exists and that a change in diet can help immensely.
Click on the chart to read the salicylate sensitivity research which is published on the NSW Government website.
Salicylate sensitivity and eczema - case study 2
Wendy* came to see me after being referred by her naturopath. Wendy had suffered from eczema since she was a child and she was now turning 50. It was head-to-toe and she had almost given up trying to treat it. The only time she was eczema-free, in the last 50 years, was during one of her pregnancies. When she came to see me I put her on the low-salicylate Eczema Diet for a few months, plus calcium as she was also avoiding dairy.
Her skin gradually improved, with the occasional flare up. After a follow-up consult we diagnosed moderate salicylate sensitivity - she could consume carrots and beetroot (medium sals) but her skin worsened when she tested/ate high salicylate ingredients such as spinach and tea. She also had moderate amine sensitivity as her skin worsened when she tried probiotics and fish oils. I prescribed Skin Friend for nutritional support and to reverse the salicylate sensitivity. Within eight months her skin had completely cleared up (this is a typical time frame for people who have had severe eczema consistently for more than twenty years). It has now been several years and she reported she was able to expand her diet to include more salicylate foods and stay eczema free.
*Name and details have been changed to protect her privacy.
How to diagnose salicylate sensitivity
The most accurate way to identify salicylate sensitivity is to avoid consuming salicylate-rich foods for a period of time (anywhere from 2 weeks to 3 months, in severe cases). Then re-introduce salicylate-rich foods into your diet and note if there are any reactions. I recommend using a diet diary to document reactions.
At the Eczema Life Clinic I also occasionally recommend/prescribe a Liver Detoxification Function Profile test, which measures how your liver processes salicylates. In this test you need to take an aspirin tablet and a caffeine tablet so people who have severe reactions to aspirin should avoid this test.
Are men and women affected differently by salicylates?
Yes and the research is fascinating. In the research by Loblay and Swain, 64% of the females who had eczema reacted to salicylates and other food chemicals, 65% had a worsening of skin rashes/hives, 72% found the food chemicals triggered headaches and 71% had a worsening of irritable bowel symptoms. However, they had a lower rate of behavioural problems at only 28%.
In contrast, males had a significantly higher rate of behavioural problems (72%) such as ADHA, aggression, irritability and poor attention span, being triggered by adverse reactions to food chemicals including salicylates. Click on the chart, below, to read the full research paper:
What causes salicylate sensitivity?
Your liver detoxifies chemicals, including salicylates in a process called Phase 1 and Phase 2 Liver Detoxification (cytochrome P450 is commonly involved).
According to research by Dr Kimata from the Department of Paediatrics and Allergy at the Ujitakeda Hospital in Kyoto (Japan) 17% to 33% of children with eczema have non-alcoholic fatty liver. This can be caused by nutritional deficiencies, low antioxidants, high sugar and/or high fat intake. In adults it's often caused by frequent alcohol consumption and high intakes of sugar and other unhealthy foods.
The causes of salicylate sensitivity include:
- Poor liver health (fatty liver, jaundice)
- Excess sugar in the diet
- Excess fats in the diet
- Nutrient deficiencies
- Acid-forming diets (too much meat, processed grains and junk food)
- High exposure to chemicals (most common)
- Unknown factors
What can be done to prevent salicylate sensitivity?
The good news is salicylate sensitivity can be prevented, even though it can take time and perseverance to be able to resume a normal healthy diet. My daughter and I previously had salicylate sensitivity. How did I know it was salicylate sensitivity? I once had a sore throat and gargled aspirin (a salicylate medication) and my throat swelled up and I had to be rushed to hospital. That was years ago. Recently I accidentally took an aspirin medication after inuring my foot (I failed to read the ingredients until after I consumed it) and thankfully I had no adverse reaction at all. So salicylate sensitivity can be reversed.
The solution is to temporarily reduce salicylates in the diet, consume easy-to-digest nutrients (i.e. supplements), get more rest, daily gentle exercise, eat healthy low-salicylate foods - not sugar-rich junk, have more healthy thoughts and less stress.
Most importantly, your liver processes salicylates, via a reaction called glycination, so it's important to improve the health of your liver. Through my work with eczema patients at the Eczema Life Clinic I have found that salicylate sensitivity slowly improves if you eat a healthy diet that is also lower in salicylates. This break from high salicylate foods is to give your liver a rest from processing salicylates and your gut lining time to heal. It's often helpful to avoid wheat and dairy (and gluten if you are sensitive to gluten).
Typical low salicylate diets are often rich in sugar, wheat and dairy, which can worsen salicylate sensitivity (as they can cause fatty liver) so avoid these. Rather than replacing salicylate-rich foods with sugar, wheat and dairy (which are all low in salicylates but a burden to your liver), eat healthy and low-salicylate recipes from The Eczema Diet. Also take note of your allergies and avoid these too.
Nutritional support for chemical sensitivity
I stress that nutritional support is essential while you are following a low salicylate diet or any diet that removes food groups. Supplementation may not be a quick fix or a magic pill that quickly suppresses eczema symptoms (as suppression brings out the symptoms in other ways - as is the case with topical steroids). Supplementation often works gradually and for deep healing to occur the eczema patient needs to be calm, well rested and caring for one's health with healthy low salicylate foods, not sugar-rich, low salicylate junk. I often prescribe Skin Friend for my patients as it offers nutritional support, it's anti-inflammatory and contains ingredients that assist in the healing and repair of the skin.
Article references, below.
NOTE: Karen's latest book The Eczema Detox is now released and is her most updated book on healing eczema with a low salicylate approach. You can read further on the difference between the two books here.
At Eczema Life, we recommend nutritionist Karen Fischer's low food chemical program (The Eczema Detox) along with additive-free supplements for skin health and wellbeing. Click on the images to view more details:
About the author
Karen Fischer is a nutritionist and the award-winning author of The Healthy Skin Diet and The Eczema Diet. Karen runs the Eczema Life Clinic in Sydney where she has consulted with hundreds of patients with eczema, TSW, psoriasis and other skin disorders. Karen's daughter previously suffered with eczema. More about Karen >>
For more information on salicylates in foods, plus amines and glutamates, download the Complete Salicylate Food Tables here when you sign up to my eczema newsletter/become a friend of Eczema Life.
Loblay, R.H. and Swain, A.R., 2006, ‘Food Intolerance’, Recent Advances in Clinical Nutrition: www.nsw.gov.au
Huang, E. S., Strate, L. L., Ho, W. W., Lee, S. S., & Chan, A. T. (2011). Long Term Use of Aspirin and the Risk of Gastrointestinal Bleeding. The American Journal of Medicine, 124(5), 426–433.
Bjarnason, I., Williams, P., Smethurst, P., Peters, T. J., & Levi, A. J. (1986). Effect of non-steroidal anti-inflammatory drugs and prostaglandins on the permeability of the human small intestine. Gut, 27(11), 1292-1297.
WARIN, R.P. and SMITH, R.J., Challenge test battery in chronic urticaria. British Journal of Dermatology, 94:401-406.
Ying, Z., Giachini, F. R. C., Tostes, R. C., & Webb, R. C. (2009). Salicylates dilate blood vessels through inhibiting PYK2-mediated RhoA/Rho-kinase activation. Cardiovascular Research, 83(1), 155–162. http://doi.org/10.1093/cvr/cvp084
Photo of oranges by Karen Fischer; product photos by Lyn McCreanor