When I first set out to uncover the root cause of my Hashimoto’s, I took an inventory of all of my symptoms to find an underlying connection.
In creating my own personal health timeline, I was able to see how the symptoms I was experiencing had developed over the years… and found a common thread that kept leading me back to gut infections.
Over the last several years of working with people with Hashimoto’s, I’ve found that many of those with chronic hives often have the gut protozoan parasite Blastocystis hominis — and that eradicating the protozoa can resolve hives, irritable bowel syndrome (IBS), and even Hashimoto’s. Scientists in Bosnia first published this connection in 2015, though I’ve seen it clinically since 2013. [1]
Many improvements in symptoms — and a reduction in antibodies — can happen after addressing a Blastocystis hominis infection.
Today, I’d like to share just how you can do that.
In this article, I’ll cover:
- The symptoms of a “Blasto” infection
- The connection between Blastocystis and hives
- How Blastocystis can cause IBS and gut issues
- Treatments to address the infection
- Common co-occurring infections
My Personal Health Timeline
My own health troubles started during my freshman year in undergrad, after catching “mono” — a common viral infection that is caused by the Epstein-Barr virus. Prior to this infection, I was a bright-eyed, bushy-tailed, and energetic young woman.
The summer before I started college, I would wake up at 5:30 or 6 am each morning so that I could go to the gym, before starting work at 8 or 9 am at the pharmacy. I loved my job as a pharmacy technician, learning about the body and medications, and couldn’t wait to start my studies to become a pharmacist! I worked full-time in the pharmacy, and spent each evening studying for the pharmacy technician certification. I was proud to be the youngest person in Illinois to become a certified pharmacy technician, even before starting college. I loved learning and being out in the world!
But all of that changed during my second semester in college. I became chronically exhausted. I often slept through my morning classes, and sometimes slept through lunch and dinner. I once even slept through a midterm exam! I found myself with a strange brain fog that made studying, and even socializing, a huge effort.
Needless to say, I didn’t do too well in college that semester. I came home the following summer feeling defeated. My parents were also really concerned, as I was a shell of my former self. I slept until 2 pm each day, was moody, and lost so much weight; people suspected that I had an eating disorder.
After much rest, I got somewhat better at the end of the summer, and went back to college. I focused all of my limited energy on my studies, and was eventually able to improve my GPA to be accepted into a competitive Doctor of Pharmacy program. While I never returned to my previous levels of energy, I learned how to be more efficient, how to compensate, and how to make sacrifices, which allowed me to succeed in all of my classes.
A few years later, while in my first year of pharmacy school, I developed irritable bowel syndrome. A few years after that, I experienced anxiety attacks, acid reflux, allergies, and hives.
A year or so later, I began to experience brain fog, hair loss, and joint pain. The fatigue persisted. A year later, I was diagnosed with Hashimoto’s.
Once I had the diagnosis, I began to spend a lot of time researching, as well as self-reflecting and self-experimenting, in order to overcome Hashimoto’s. My symptoms and research kept leading me back to the gut…
I learned that I not only had food sensitivities and a lack of beneficial bacteria, but I also had gut infections: small intestinal bacterial overgrowth (SIBO), H. pylori, yeast overgrowth, and Blastocystis hominis.
It was at this point that I began to realize the role that infections can play in Hashimoto’s, and dove deeper into uncovering these root causes that can affect so many of us.
What is Blastocystis hominis?
Blastocystis hominis (for the purposes of this article, we’ll be using the term “Blasto,” but be sure not to confuse it with Blastomycosis, a rare fungal infection) is a microscopic single-cell organism (protozoan) that commonly lives in the digestive tract. It is most commonly contracted through contaminated food or water sources. While there are many protozoans that normally live in the gastrointestinal tract and are harmless or even helpful, others can cause disease.
Symptoms of Blastocystis hominis can include bloating, diarrhea, nausea, flatulence, variable bowel habits, abdominal pain, hives, and fatigue. [2]
Blasto can also cause carbohydrate intolerance. [3]
Additionally, I’ve found this pathogen is notorious for causing multiple food sensitivities. A true food sensitivity, like celiac disease, usually results in a resolution of symptoms once the triggering food is removed, but people with Blastocystis hominis infections will have multiple food sensitivities and will keep getting more. Interestingly, the Blastocystis Research Foundation reports that people with Blastocystis hominis often find that they are sensitive to gluten, dairy, soy, sugars, starches, grains, caffeine, fruit, and carbonated beverages, and removing these foods can keep symptoms at bay. [4]
Histamine sensitivity may also be related to this infection. [5] I was personally able to add back almost every food (besides gluten and dairy) after addressing Blastocystis hominis. I often wonder how many individuals who aren’t benefiting from the most popular Hashimoto’s diets (or hitting plateaus with these diets) actually have Blastocystis hominis.
In 2015, 35 percent of my clients reported testing positive for Blasto. I have found this parasite in a large subset of my clients with Hashimoto’s, especially in those who develop an Epstein-Barr Virus (EBV) infection in adulthood, and then are “never quite the same.” This could be because EBV and other herpes viruses feed on the amino acid arginine, and can thus cause a depletion of this amino acid, which normally suppresses Blastocystis hominis. (As a side note, arginine may also be helpful in energy production, and thus this may be a reason why we see so much fatigue with EBV.)
Blastocystis hominis has been found in some asymptomatic carriers, and researchers hypothesize that other factors can influence the pathogenicity of this parasite, such as the immune status of the host, one’s parasitic load, the presence of a gut imbalance, or other factors that can influence the behavior of parasites. [6]
Many conventional physicians will say that there is no need to treat it. However, eradicating Blasto has been shown to help Hashimoto’s. [7]
A study published in 2020 measured the free T3, free T4, TSH, anti-TPO, and Interleukin (IL)-17 (which mediates inflammation) levels of 20 people with Hashimoto’s, 20 people with Hashimoto’s and a Blastocystis hominis infection, and 20 people with neither condition. Interleukin (IL)-17 was significantly higher in those with Hashimoto’s who were infected with Blastocystis hominis, compared with Hashimoto’s patients who were not infected. After Blasto was eradicated, TSH, anti-TPO, and IL-17 were significantly decreased. Researchers concluded that the treatment of Blastocystis hominis infections improves Hashimoto’s through reductions in Interleukin (IL)-17, anti-TPO, and TSH levels. [8]
While this parasite might not be everyone’s root cause, I am happy that scientists have validated that it can be a trigger for some people, and that in some cases, remission can be achieved.
Furthermore, there are multiple studies implicating Blasto’s role in IBS and hives (two conditions that are very commonly associated with Hashimoto’s). [9]
The Hashimoto’s, Hives, IBS, and Blastocystis Connection
Did you know that people with Hashimoto’s are more likely to develop the skin condition chronic spontaneous urticaria (also known as chronic hives), which is manifested by widespread, itchy and swollen skin rashes? These hives can be very distressing, and they can seem to come up randomly. However, they are quite common; in fact, forty-two scientific studies have linked Hashimoto’s with chronic hives! (Some studies also suggest that taking thyroid hormone can clear up these recurring hives.) [10]
In my clinical experience, people with Hashimoto’s are also more likely to develop irritable bowel syndrome (IBS), a chronic condition that affects the large intestine and often shows up before one’s Hashimoto’s diagnosis. This condition can manifest as either diarrhea or constipation, or both, and may also cause excess gas, bloating, abdominal pain, and cramping that is often relieved after passing a bowel movement. [11]
As mentioned previously, a Blasto infection can manifest as symptoms related to the skin (i.e. hives) and gut, but there is much controversy about this protozoan. Some studies, namely from Thailand and Mexico, suggest that this is a commensal (harmless) organism (up to 20 percent of “healthy controls” may have Blasto without any symptoms). Thus, doctors may be told that there is no need to treat it. [12]
However, studies from Europe, Australia, and the Middle East, have connected this pathogen to not just chronic hives, but also irritable bowel syndrome, both of which are very common manifestations in the early stages of Hashimoto’s. [13]
This begs the question… are hives, IBS and Blasto all connected? Let’s take a look at the current research.
Blastocystis, Hashimoto’s and Hives
Blasto may be present in up to 50 percent of people in developing countries. [14]
A study of 54 people in Egypt with chronic urticaria (hives) revealed that Blastocystis hominis was found in 61 percent of them, while only eight percent of the healthy controls had the parasite. Researchers have suggested that the amoeboid form of Blastocystis hominis is more infectious than the protozoa form, and that it can adhere better to gut cells. Interestingly, the Egyptian study found this form in 60.6 percent of the Blastocystis infected people with hives, while none of the Blastocystis infected controls had this form. [15]
In a letter to the editors of the British Journal of Dermatology, Dr. Tilo Biedermann from the Ludwig Maximilian University of Munich, reported that urticaria and reactions to NSAIDs subsided after treating 10 subjects infected with Blastocystis, with paromomycin (25 mg/kg), for 10 days. [16]
Another drug, called Alinia (nitazoxanide), is an FDA-approved antiprotozoal for treating other parasites, and has been helpful in eradicating Blastocystis hominis. One study showed that it eliminated symptoms in 36 of 42 (86 percent) of patients who were put on a four-day treatment of nitazoxanide. [17] This was exciting news, as the parasite had been shown in other studies to be highly resistant to Flagyl (metronidazole), the usual drug of choice. [18]
A 2014 study found that almost 25 percent of people with chronic urticaria also had Hashimoto’s, and addressing an underactive thyroid with levothyroxine (T4 thyroid medication) could result in a clinical remission of hives. [19]
However, I do wonder if the medication is just masking the symptoms of the parasite.
Blastocystis, Hashimoto’s, and the Gut
Various studies using many different methods for parasite identification, have found the prevalence rate of Blastocystis hominis to be between 13 to 73 percent of people with irritable bowel syndrome. [20] As parasite detection methods are not 100 percent reliable (and can give many false negatives), these rates could be even higher.
Studies have found that Blastocystis species of protozoa do not invade the colonic mucosa, but they do lead to disturbances of the barrier function and increased intestinal permeability, or leaky gut, which we know predisposes us to autoimmunity. [21] Blastocystis hominis does this by breaking down secretory IgA (the protective barrier that is considered to be the GI tract’s first line of defense) and the immune system of its infected host.
The good news is that research has found that eradicating Blastocystis hominis in cases of urticaria and IBS, often leads to the remission of both conditions. [22]
Many of my clients have also been able to reduce their joint pain, fatigue, and TSH and TPO counts, by eliminating Blasto.
I was super excited to learn that a paper had been published in a medical journal, detailing the case of a person who saw a reduction in TSH and thyroid antibodies after the eradication of Blastocystis hominis! [23] In this case, a 49-year-old man who presented with chronic urticaria, was found to also have Hashimoto’s, even though he never had clear symptoms.
Blastocystis hominis was isolated through a stool examination, and the patient was given a two-week treatment with metronidazole, after which the Blastocystis hominis was eradicated and the urticaria disappeared. During the four years of follow-up, the patient presented without any symptoms. His thyroid hormones were normalized, and his anti-thyroid antibodies had declined.
I’ve found that eradicating a Blastocystis hominis infection in a person with Hashimoto’s often leads to a remission of Hashimoto’s, with an improvement in symptoms, a reduction in food sensitivities, and a reduction in thyroid antibodies.
Testing for Blasto
If you suspect you may have a Blasto infection (like 35 percent of my clients do), you may want to consider ordering a non-invasive functional medicine stool test. Tests that check for this infection include:
- GI-MAP – This panel includes bacteria, viruses, opportunistic organisms, normal flora, parasites, and fungi. The DNA/PCR techniques that are employed by this assessment also measure one’s antibiotic resistance genes and virulence factors that contribute to pathogenicity.
- GI Effects 3 day + H. Pylori – This panel screens for ova, parasites, bacteria, fungi, yeasts, and occult blood. It also checks for antigens to Helicobacter pylori, Entamoeba histolytica, Cryptosporidium parvum, and more.
- GI Effects Comprehensive Profile – This panel from Genova Diagnostics uses DNA analysis to go beyond the standard parameters for identifying gastrointestinal disorders.
- Comprehensive Stool Analysis (Doctor’s Data Kit) – The Comprehensive Stool Analysis evaluates the status of beneficial and imbalanced commensal bacteria, pathogenic bacteria, fungi, and yeast.
- Gut Zoomer 3.0 Complete – The Gut Zoomer 3.0 Complete is the most comprehensive stool test that analyzes over 300 microorganisms in your large intestine with 99 percent specificity and 98 percent sensitivity, and with very high levels of accuracy in the detection of pathogenic microorganisms. Among a wide array of pathogens, it can detect bacteria (e.g. H. pylori, E. coli), parasites (e.g. Blastocystis hominis, Giardia), worms (roundworms, tapeworms), fungi (Candida albicans), and viruses (e.g. EBV). This test can help identify imbalances in your gut microbiome, which can lead to many health issues, such as gastrointestinal symptoms, skin conditions, autoimmune disorders, and more.
Treatment Options
According to the Blastocystis Research Foundation, “Some patients can manage symptoms with an extensive exclusion diet, which may include the exclusion of refined sugar, wheat, dairy products, rice, corn, carbonated drinks, tea, coffee, alcohol, and fruit.” [24] (Does this sound familiar? If you’ve read my article on the best diet for Hashimoto’s, you’ll know that many people with Hashimoto’s have managed their symptoms with similar diets.)
While diet can help to manage symptoms, it will not eradicate the pathogen. This parasite needs to be treated with antiprotozoal medications, and/or herbs with antiprotozoal activity, and/or the beneficial yeast Saccharomyces boulardii.
I have seen the following protocols for eradicating Blastocystis hominis to work effectively:
Medications
- A triple therapy used in Australia combines three medications to eradicate the infection: diloxanide furoate, trimethoprim/sulfamethoxazole, and secnidazole.* [25]
OR
- Alinia is another antiprotozoal medication that can be taken for three days on, then two weeks off, repeated twice.* (This ensures that we address more than one “life-cycle” of the parasite, so that we can access it when it’s in its more vulnerable state.) [26]
*Keep in mind that antiprotozoal medications can lead to yeast overgrowth, and treatment with anti-yeast herbs or a medication like Nystatin may be necessary to rebalance the gut.
Natural Treatment Options
The beneficial yeast Saccharomyces boulardii may help eradicate Blastocystis hominis (when two capsules are taken twice per day, for at least 30 days, but ideally for 60 days). In fact, one study found that S. boulardii was just as effective as the antibiotic metronidazole in the treatment of a group of children who presented with gastrointestinal symptoms (abdominal pain, diarrhea, nausea-vomiting, flatulence) from the confirmed presence of Blasto by stool examination. [27] They were given 250 mg of S. boulardii, twice a day for ten days, then tested periodically until they received a “clinical cure rate” of 94.4 percent after 30 days. This has become my go-to treatment in many cases, as I have seen excellent results from an S. boulardii supplement alone, and rarely recommend protozoal medications and aggressive protocols to eradicate Blasto anymore (at least not as a starting point).
Functional medicine practitioners typically use a combination of berberine and oil of oregano for various gut infections, including parasites, SIBO, yeast, and dysbiosis, because they have antimicrobial properties. These days, I sometimes add berberine and oil of oregano to S. boulardii for Blasto, especially if a person has other types of infections, including H. pylori and/or strep. [28]
I first learned about berberine about a decade ago, while attending functional medicine conferences to learn more about how to heal my own Hashimoto’s. I remember speaking to a few doctors who mentioned that berberine seemed to help their Hashimoto’s patients feel better and reduce thyroid antibodies. I have not seen this in the published research, but I wonder if this improvement is due in part to the antimicrobial activity. Berberine contains compounds called alkaloids that have broad-spectrum antimicrobial and antiparasitic properties. [29]
In addition to its impact on gut infections, berberine also has blood sugar balancing properties (blood sugar issues are so common in Hashimoto’s), and has been super helpful to me and my clients in eliminating pesky chin hairs! [30]
Because I’ve found this supplement to be so helpful for my clients, I developed a Berberine formulation as part of my Rootcology supplement line, which contains 400 mg of the plant alkaloid berberine (from Berberis aristata), using Evail™ technology, an all-natural formulation that improves the absorption and delivery of berberine. I also like Berberine 500 by Vital Nutrients.
Oil of oregano is typically used for yeasts and mold, but it also has strong antiparasitic properties. It is also used frequently in cases of SIBO.
While my first line recommendation has undoubtedly become S. boulardii for most people, in cases of resistant Blasto, combining Oil of Oregano and Berberine with S. boulardii, for 60 days, may be helpful. [31]
In addition to Rootcology Oil of Oregano, Oil of Oregano from Designs for Health is another quality product that I recommend.
Alternative or Add-On Options
As I mentioned, I generally recommend an S. boulardii supplement, and sometimes berberine and oil of oregano, and I really don’t see a lot of issues with resistance or intolerance. That said, in the case of resistance, or the inability to tolerate certain products, I am always learning new things and sharing them with my readers and clients.
Interestingly, two additional antimicrobials that I like to recommend for people who have various gut infections may also have anti-Blasto properties (at least in Petri dishes):
- Garlic Oil contains allicin, a sulfur-containing garlic extract with antiparasitic activity. Allicin has been shown to be effective against protozoa such as Blastocystis hominis by inhibiting the replication and invasion of these parasites. [32] I first learned about using garlic extracts for Hashimoto’s when I read a short, yet insightful self-published book. This gentleman reported that his Hashimoto’s went into remission after using garlic extract! At the time, most of the garlic extracts on the market contained dairy, so I didn’t try it for myself, but now typically recommend dairy-free garlic extracts for sulfur-SIBO and various other infections.
- Black Cumin Seed Extract is something I didn’t initially use to get my Hashimoto’s into remission, but found out about it a few years ago when studies showed that it had thyroid benefits. This versatile herb has been called “a cure for everything but death.” While I can’t vouch for that, it is interesting to note that black cumin seed is an herb used for lactation! I was four months postpartum when I had a Hashimoto’s flare-up, along with a scratchy, hoarse voice. (For the first few weeks, I thought it was just from screaming during childbirth, haha.) It turned out that I had H. pylori, a common thyroid trigger, and none of my usual protocols were breastfeeding-friendly. At the advice of my wonderful herbalist MD friend Maya Shetreat, I tried black cumin seed extract (also called black seed oil or black cumin), which helped me get rid of the H. pylori and the flare-up. In addition to anti-H. pylori effects, black cumin seed has been shown to have antiparasitic effects on a variety of parasites, including Blastocystis hominis. Black cumin seed extract is also effective for treating Entamoeba histolytica, Giardia, and Pentatrichomonas infections. [33] Rootcology’s Black Cumin Seed Extract is a unique blend containing 125 mg tocotrienols (a type of vitamin E) along with 1 g black cumin seed oil (Nigella sativa) per serving, in capsule form, for a synergistic combination. Alternative black seed oil supplements that may be helpful include Designs for Health Annatto-E Synergy, Amazing Herbs Black Cumin Seed (ground), and Organic Black Seed Oil (cold-pressed).
I recommend that you talk to your doctor before using any of these supplements, to ensure that they are right for you.
Treatment Tips
The key is to use these treatments long enough, or in a pulsed fashion, to fully eradicate Blasto.
Blasto can take on four different forms during its lifecycle, and some of the forms are resistant to treatment. [34]
The forms range from the cyst stage (when infection is thought to occur), to vacuolar, amoeboid, and granular stages, until they return to cyst form, often repeating the cycle. The cyst is the most resistant form of Blasto, and is able to survive in harsh conditions because of its thick multilayered cyst wall. Therefore, it’s important to stay on a treatment long enough to eradicate the parasite during one of its other forms in the cycle. [35]
In theory, lipase-containing digestive enzymes (such as Veggie Enzymes and Pancreatic Enzymes Plus), taken while one is using other treatments for the Blasto infection, could help with making the parasite more vulnerable to the treatments, by breaking down the cyst wall. I used to recommend lipase-containing enzymes for resistant cases of Blasto, sometimes with arginine (which, according to some researchers, can help with eradicating it), along with more aggressive treatment options. As I mentioned earlier, in the last few years, I’ve had such great results with S. boulardii alone (and it’s generally well tolerated and cost-effective), that I usually start there.
Removing food sensitivities will also be very helpful for managing symptoms while recovering from Blasto.
Please be sure to work with your practitioner to determine which treatment option is best for you.
When you work with your functional medicine practitioner, be sure to ask about potential co-occurring infections. Often, Blastocystis co-occurs with H. pylori, another potential root cause and trigger of Hashimoto’s. (You can read more about H. pylori in my article here.) Some professionals will go as far as to treat a person for both infections when one or the other is found.
The Takeaway
Some people with Hashimoto’s can completely reverse their condition just by going gluten and dairy free, and some see no improvement at all from doing so. Gluten and dairy are common leaky gut triggers, but there are many others. Testing for gut infections could be an important next step on your road to uncovering your root causes. If this sounds like your story, I urge you to listen to your body — or should I say, gut feeling? 🙂 — and look into other possible root causes — like a Blasto infection.
Addressing infections can make a dramatic difference in your health journey. However, some people may need to dig further and address the other root causes of their remaining symptoms.
I cover steps on how to search for your personal root causes, as well as a Blastocystis hominis protocol, in my book, Hashimoto’s Protocol… so be sure to check it out if you haven’t done so already.
I hope this information helps you on your journey!
P.S. Be sure to sign up for my weekly newsletter to get a free chapter of my first book, recipes, a Thyroid Diet start guide, and notifications about upcoming events. I love interacting with my readers on social media, and I encourage you to join my Facebook, Instagram, TikTok, and Pinterest community pages to stay on top of thyroid health updates and meet others who are following similar health journeys.
References
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[2] Sugiyama A, Nishie H, Takeuchi S, Yoshinari M, Furue M. Hashimoto’s disease is a frequent comorbidity and an exacerbating factor of chronic spontaneous urticaria. Allergol Immunopathol (Madr). 2015;43(3):249-253. doi:10.1016/j.aller.2014.02.00; Zuel-Fakkar NM, Abdel Hameed DM, Hassanin OM. Study of Blastocystis hominis isolates in urticaria: a case-control study. Clin Exp Dermatol. 2011;36(8):908-910. doi:10.1111/j.1365-2230.2011.04127.x
[3] Yason JA, Liang YR, Png CW, Zhang Y, Tan KSW. Interactions between a pathogenic Blastocystis subtype and gut microbiota: in vitro and in vivo studies. Microbiome. 2019;7(1):30. Published 2019 Mar 11. doi:10.1186/s40168-019-0644-3
[4] Diagnosis | Blastocystis Research Foundation. Blastocystis Research Foundation. http://www.bhomcenter.org/info/diagnosis.htm. Accessed June 30, 2017.
[5] Biedermann T, Hartmann K, Przybilla B. Hypersensitivity to non-steroidal anti-inflammatory drugs and chronic urticaria cured by treatment of Blastocystis hominis infection. British Journal of Dermatology. 2002;146(6):1113-1114
[6] Lepczyńska M, Białkowska J, Dzika E, Piskorz-Ogórek K, Korycińska J. Blastocystis: how do specific diets and human gut microbiota affect its development and pathogenicity?. Eur J Clin Microbiol Infect Dis. 2017;36(9):1531-1540. doi:10.1007/s10096-017-2965-0
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[10] Zuel-Fakkar NM, Abdel Hameed DM, Hassanin OM. Study of Blastocystis hominis isolates in urticaria: a case-control study. Clin Exp Dermatol. 2011;36(8):908-910. doi:10.1111/j.1365-2230.2011.04127.x; Levy Y, Segal N, Weintrob N, Danon YL. Chronic urticaria: association with thyroid autoimmunity. Arch Dis Child. 2003;88(6):517-519. doi:10.1136/adc.88.6.517
[11] Patil AD. Link between hypothyroidism and small intestinal bacterial overgrowth. Indian J Endocrinol Metab. 2014;18(3):307-309. doi:10.4103/2230-8210.131155
[12] Poirier P, Wawrzyniak I, Vivarès C, Delbac F, El Alaoui H. New Insights into Blastocystis spp.: A Potential Link with Irritable Bowel Syndrome. PLoS Pathogens. 2012;8(3):e1002545. doi:10.1371/journal.ppat.1002545.
[13] Irritable Bowel Syndrome. Mayo Clinic. https://www.mayoclinic.org/diseases-conditions/irritable-bowel- syndrome/symptoms-causes/syc-20360016. Updated March 17, 2018. Accessed April 30, 2018.; Poirier P, Wawrzyniak I, Vivarès C, Delbac F, El Alaoui H. New Insights into Blastocystis spp.: A Potential Link with Irritable Bowel Syndrome. PLoS Pathogens. 2012;8(3):e1002545. doi:10.1371/journal.ppat.1002545.
[14] Salehi M, Mardaneh J, Niazkar HR, et al. Prevalence and Subtype Analysis of Blastocystis hominis Isolated from Patients in the Northeast of Iran. J Parasitol Res. 2021;2021:8821885. Published 2021 Jan 13. doi:10.1155/2021/8821885
[15] Zuel-Fakkar NM, Abdel Hameed DM, Hassanin OM. Study of Blastocystis hominis isolates in urticaria: a case-control study. Clin Exp Dermatol. 2011;36(8):908-910. doi:10.1111/j.1365-2230.2011.04127.x
[16] Biedermann T, Hartmann K, Przybilla B. Hypersensitivity to non-steroidal anti-inflammatory drugs and chronic urticaria cured by treatment of Blastocystis hominis infection. British Journal of Dermatology. 2002;146(6):1113-1114. doi:10.1046/j.1365-2133.2002.473212.x.
[17] Rossignol JF, Kabil SM, Said M, Samir H, Younis AM. Effect of nitazoxanide in persistent diarrhea and enteritis associated with Blastocystis hominis. Clin Gastroenterol Hepatol. 2005 Oct;3(10):987-91.
[18] Rajamanikam A, Hooi HS, Kudva M, Samudi C, Kumar S. Resistance towards metronidazole in Blastocystis sp.: A pathogenic consequence. PLoS One. 2019;14(2):e0212542. Published 2019 Feb 22. doi:10.1371/journal.pone.0212542
[19] Sugiyama A, Nishie H, Takeuchi S, Yoshinari M, Furue M. Hashimoto’s disease is a frequent comorbidity and an exacerbating factor of chronic spontaneous urticaria. Allergol Immunopathol (Madr). 2015;43(3):249-253. doi:10.1016/j.aller.2014.02.00
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Note: Originally published in September 2015, this article has been revised and updated for accuracy and thoroughness.
