My asthma, eczema, allergies, and hives have greatly decreased in severity since I’ve gotten to a more optimal dose of thyroid hormone, and eliminated yellow #5 food color from my diet. I have Graves’ disease, which is an autoimmune thyroid condition, so by definition, my immune system is dysfunctional. Insufficient thyroid hormone is a stress on the body, because there is not enough energy to keep all systems running smoothly. Taking enough thyroid hormone greatly relieves this stress, and for many Hashi’s patients, causes their anti-thyroglobulin and anti-thyroid peroxidase antibodies to decline.  In other words, having adequate thyroid levels lessens the severity of immune dysfunction.
Asthma, low cortisol, and low thyroid levels
Wheezing and breathing problems were something that plagued me every night after dinner, no matter what I ate, when my thyroid levels were too low. What was so confusing was that I could have a can of soup at lunchtime and be ok, and then the next day, have the exact same flavor of soup before bed, and would end up wheezing. How could I be allergic to something one day, and not the next? It made no sense.
Cortisol, the hormone that deals with stress and inflammation, is highest in the morning and lowest at night, and this might explain why what was tolerated at lunch was not tolerated at night. One study found that asthmatic children with significantly lower cortisol levels at night had the worse Forced Expiratory Volume compared to controls.  Cortisol moderates inflammation in the body, including the lungs. With less cortisol, there is more inflammation. Cortisol levels positively correlate with thyroid levels , so it would be a reasonable hypothesis to say that low thyroid levels caused the low cortisol levels, and therefore, raising thyroid levels would raise cortisol, and asthma would disappear. Others have observed this correlation too.  It certainly is true in my case. Could the asthma epidemic actually be a hypothyroidism epidemic in disguise?
Asthma correlates with low thyroid levels in several studies. One study examined hypothyroid patients (from total thyroidectomy and RAI for cancer) who had no pulmonary (lung) disease. There was a significant increase in non-specific bronchial reactivity in these nonasthmatic subjects when hypothyroid and untreated, than when treated with thyroid hormone.  In another study, chronic bronchial asthma patients were given T3 daily for 60 days. Peak flow increased in all patients, with an average increase of 25%.  A third study examined the effect of T3 for 30 days on children with bronchial asthma. These children were not considered to be hypothyroid based on symptoms, yet 30% were able to stop their antiasthmatic medications while continuing the T3 treatment, and 13% reduced the amount of bronchodilators needed. All patients noted a significant improvement in pulmonary function tests. 
Yellow #5 food color or tartrazine gives me hives and eczema
Many eczema and hives attacks I experienced were caused by a food color called yellow #5 or tartrazine. It is found in many unrelated processed foods, which is why it was so difficult to figure out. Pickles, jello, macaroni and cheese, and chocolate mint cookies are hardly in similar food groups, but yellow #5 is found in all of these products. And yes, I have learned my lesson and now eat mostly whole foods from scratch. Dining out is still problematic, however, because there is really no way to tell if yellow #5 is one of many ingredients used in a dish. I do try to avoid anything that’s bright orange, yellowish, or light green though. I have even found yellow #5 in certain brands of toothpaste and vitamins, so check everything that goes into your mouth.
Yellow #5 reactions are often caused by a defect in phase 2 liver processing called sulfation. Sulfates attach to salicylates (found in fruits), phenols (found in food dyes like yellow #5 and preservatives), hormones and neurotransmitters, and other toxins, making them more soluble so they can be cleared from the body. But some of us lack sulfates or the enzyme phenol sulfotransferase (PST) to perform this detox, so we break out in hives or have an asthma attack.  When the body tries to process out yellow #5, it will exhaust the already low sulfate/PST levels that exist. Magnesium sulfate baths (epsom salt) have been reported to be helpful, because they provide sulfate through the skin. Molybdenum in low doses has also been reported to help asthmatics, who tend to be low in this trace mineral , maybe because it is part of an enzyme reaction that neutralizes sulfites.  Asthmatics tend to react to sulfites, yellow #5, and aspirin. 
Autistics tend to have this PST deficiency , along with a high copper/low zinc ratio , which is also found in asthmatics. [9,10] I have never been diagnosed as autistic though I have had allergies from infancy.
Aspirin and sulfites both make me wheeze, yellow #5 gives me hives and eczema, and a sulfa antibiotic sent me to the ER in anaphylactic shock (puffed up, turned blue, got the shakes, BP dropped, was so cold I needed 4 blankets and was still shivering, etc.). Hypersensitivity to anticonvulsants and sulfa antibiotics has been noted in other thyroid patients, so anyone with a known thyroid condition might be wise to choose another type of antibiotic.  Beer is another major allergen for me, though I’m not sure how it fits in here. It made my throat swell so badly that I lost my voice for a week. Beer does have sulfites, but it also has hops, an ingredient I’ve only found in beer.
My skin and lungs are now clear 99% of the time, with no more daily outbreaks of hives or wheezing. My symptoms return when my thyroid dose is too low, so I believe optimal thyroid levels improve the sulfation pathway. It’s possible adequate thyroid levels also raise the threshold amount that invokes a reaction, since the quantities that cause reactions have such a broad range. The highest amount of aspirin that produced a response in susceptible subjects was 415 times greater than the smallest amount. For yellow #5 the highest amount was 260 times greater.  I know I have had small amounts of sulfites without a reaction (balsamic vinegar!) now that I’m on a higher thyroid dose. The thyroid gives the liver the energy to perform its functions, and since sulfation is a liver process, one could conclude that low thyroid levels causes asthma. As mentioned earlier, low thyroid levels also cause low cortisol, which is implicated in asthma, so there’s another reason to keep thyroid levels optimal.
Are asthma and hives attacks more common during the month of October? Could there be a connection? Here’s the story of how I determined my yellow #5 sensitivity: Hives, yellow #5 and Halloween candy.
Getting your thyroid tested
If you’d like to have your thyroid levels tested, please ask for these thyroid tests, and note where your levels are in the thyroid lab ranges compared to healthy people. If you do not ask for these specific tests, your doctor will most likely just run a TSH test, which sadly, does not catch many cases of hypothyroidism. [TSH levels do not reflect thyroid levels]
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- Anneke M. Landstra, Dirkje S. Postma, H. Marike Boezen, And Wim M. C. Van Aalderen. Role of Serum Cortisol Levels in Children with Asthma. American Journal of Respiratory and Critical Care Medicine, Volume 165, Number 5, March 2002, 708-712. http://www.ncbi.nlm.nih.gov/pubmed/11874819?dopt=Abstract
- Sonia C Dumoulin, Bertrand P Perret, Antoine P Bennet and Philippe J Caron. Opposite effects of thyroid hormones on binding proteins for steroid hormones (sex hormone-binding globulin and corticosteroid-binding globulin) in humans. European Journal of Endocrinology, Vol 132, Issue 5, 594-598, 1995. http://www.eje-online.org/cgi/content/abstract/132/5/594
- Autism, PDD, Aspergers Discussion. [internet] Feingold Association of the United States. Updated: 2/15/2010. http://www.feingold.org/autism-more.php
- Han Ziying,Tu Yiping, Yang Ying, Jin Xiaoyan, Zhu Guizhi. Study on the Contents of Ten Kinds of Necessary Trace Elements in Serum of Sufferers from Allergic Asthma. 1996. http://en.cnki.com.cn/Article_en/CJFDTOTAL-GWYS609.006.htm
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- Scott Faber, Gregory M. Zinn, John C. Kern II, H. M. Skip Kingston. The plasma zinc/serum copper ratio as a biomarker in children with autism spectrum disorders. Biomarkers. May 2009, Vol. 14, No. 3 , Pages 171-180. http://informahealthcare.com/doi/abs/10.1080/13547500902783747?select23=Choose
- H. Vural, K. Uzun, E. Uz, A. Koçyigit, A. Çigli and Ö. Akyo. Concentrations of copper, zinc and various elements in serum of patients with bronchial asthma. Journal of Trace Elements in Medicine and Biology Volume 14, Issue 2, June 2000, Pages 88-91. http://www.ncbi.nlm.nih.gov/pubmed/10941719
- el-Kholy MS, Gas Allah MA, el-Shimi S, el-Baz F, el-Tayeb H, Abdel-Hamid MS. Zinc and copper status in children with bronchial asthma and atopic dermatitis. J Egypt Public Health Assoc. 1990;65(5-6):657-68. http://www.ncbi.nlm.nih.gov/pubmed/2134100
- Dr. David Derry Answers Reader Questions. Brought to you by Mary Shomon, Your Thyroid Guide. Topic: Asthma and Thyroid Hormone. http://thyroid.about.com/library/derry/bl10.htm
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- Ismail AA, Shalaby E, Gadalla I. Effect of triiodothyronine on bronchial asthma. II. J Asthma Res. 1977 Apr;14(3):111-8. http://www.ncbi.nlm.nih.gov/pubmed/903344
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