Fungal Infections, Histamine Intolerance, and Mast Cells

October 16, 2014  |  Blog, Histamine Intolerance

Fungal infections, histamine intolerance, and mast cells have a crucial connection which is often overlooked as one source of histamine intolerance.

It is common to talk about mast cells as part of an allergic (even anaphylactic) reaction. But their role in allergic reactions is only a small part of the job of the mast cell. Another crucial role mast cells play is in identifying and treating pathogen; such as bacteria, viruses, parasites and fungi.

Mast cells reside strategically through-out the body in tissues that are commonly exposed to the external environment, such as the skin, airways and the gut. There they are one of the first cells to make contact with pathogens.

For this life-saving task, the mast cells are perfectly equipped. They are heavily armed with mediators (molecules such as histamine, TNF and interleukins), that can be released upon contact with pathogens.


The mast cell is designed to identify pathogens. When they identify pathogens they trigger the acute inflammatory mediators which call more cells into the infected site. Histamine, for instance, increases blood flow to the damaged site and make the vessels “leakier”. This leakiness allows the other inflammatory mediators access. There they combine forces with free radicals to “eat” the infection.


Mast cells are able to identify molecules on the surface of bacteria. These molecules bind to receptors on the surface of mast cells and trigger the release of inflammatory mediators including histamine. Also, mast cells release molecules (proteases and cathelicidins) that can directly kill bacteria.

Viral Infections

When it comes to viral infections, the process is very similar. Mast cells can be activated by viruses via a specific cell surface receptor, which triggers the release of mediators (mainly interferon) that elicit an antiviral immune response. However, there is evidence that mast cells can also be harmful in viral infections. One study showed that in response to respiratory virus, mast cells could exacerbate or lead to the development of asthma.


The same principles apply to parasitic infections. Mast cells are preferentially located in tissues targeted by parasites, e.g., the skin and gut. These mast cells express receptors that identify specific parasitic components. Upon activation, mast cells release several inflammatory mediators that trigger the immune response, necessary to get rid of the parasites.

Fungal Infections

The role of mast cells in fungal infections is a lot less clear. Similarly to parasites, fungi enter the body via mast cell rich organs (skin, gut and airways), and it is also known that mast cells have receptors that can recognise fungi and trigger anti-fungal responses. Mast cells produce several molecules (interleukins, interferon and more) that have been shown to be involved in protective host responses to fungal pathogens. Although there is a lack of scientific studies on fungal infections it’s highly likely that mast cells are also important players in the fight against fungal infections.

Histamine Intolerance

The gastrointestinal tract, as well as the skin, have the highest amount of mast cells (in a normal state). During an infection the number of mast cells will rapidly increase in the gut. As the mast cells increase, and interact with the pathogens, they release more inflammatory mediators (including histamine). If the histamine load exceeds the ability to degrade it then the result will be histamine intolerance.

Candida and Food Allergies

Studies show that if your gut is colonised with the fungus Candida you are likely to become sensitive against food antigens (food allergy), because of the increased number of mast cells, and the hyper permeability of the gastrointestinal mucosa (which is caused by histamine release).

If you have histamine intolerances and food allergies it is very important to test for pathogens. As a minimum they can be contributing to the histamine load if you have a histamine related disease. They could also just be the cause.

Further Reading

Saluja R, Metz M, Maurer M, “Role and relevance of mast cells in fungal infections,” Front Immunol. 2012 Jun 13;3:146.

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  • Dot SLady

    Can you explain the difference between a fungal infection (yeast?) and candida; I thought they were the similar and/or the same.

    • Hi Dot there are many types of fungus. Not all of them are Candida. Candida is just one type of yeast. For example, I know the doctors data 3 day stool test distinguishes between Candida and other forms of yeast. As I understand it, where there are low levels of good bacteria, the yeast is opportunistic, and moves in to occupy the space. Getting up good bacteria as a general principle deals with non Candida based yeast.

      • Dot SLady

        I’m finally getting the Doctor’s Data 3-day stool test Alison! Thanks for the heads up. Do patients with dysbiosis all have symptoms of one sort or other?

        • Awesome. Its so worthwhile. Gut. Liver. Methylation. is general sequence.

  • Philip Clax

    I have sebbhoreic dermatitis which is a type of fungal problem, I wonder if this could also be linked to my histamine issues.

    • LyndaF

      I know this is a rather belated reply, but my sebhoric dermatitis seems to be a histamine intolerance symptom. When I eat low histamine it goes away, high histamine food brings it back. Also, Head and Shoulders helps partly because its active ingredient works against histamine on the scalp. Other antifungal shampoos(without that ingredient) did nothing at all for me.

      • Philip Clax

        Thanks so much Lynda, is there a particular head and shoulders you use? I’m going to try it. My dermatitis definitely gets much worse too when my diet is bad.

        • LyndaF

          Hi Philip,
          I don’t think it has to be the brand name as long as it has 1%pirithione zinc. I use the 2 in 1 for itchy scalp but the regular version helps too.
          I have just started taking oral Lamisil for a toenail fungus so I am curious to see if lowering my fungal load will affect my histamine intolerance.

  • Olya Konovalova

    So HIT is related to candida overgrowth and parsites? But it can’t be treated as usual by ingesting probiotics and cultured food since it’s high in histamines. What to do then?

    • Olga not all HIT is caused by candida and parasites. Also not all probiotics are high in histamines. Many people take histamine reducing probiotics very successfully

      • Olya Konovalova

        Yes, makes sence. I read that bifidobacterium are usually suitable for people with histamine intolerance.

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  • disqus_6DbrMJ2WvJ

    HI Alison, How can I confirm that histamine or candida are the cause of my problems? I feel like I’ve been chasing rabbit trails and I want to finally do something that makes a difference. – Julie

    • You are welcome to make an appointment with me. I can help you get the necessary testing and confirmation, and assist with a treatment protocol.

      • disqus_6DbrMJ2WvJ

        How much do you charge? Do you take TriCare Insurance?

        • Unfortunately i dont take insurance perhaps you can fiind a functional docyor or naturopath near you who does. I am also able to consult with them.

  • Rhonda Heath-Cowan Riker

    how do i ask for Pathogen test?

    • You will need to work with a functional practitioner. I can order tests for you if you are my client or you would need to find a functional doctor.

  • Luxie Ryder

    I’ve got so much going on that I don’t even know what kind of help I need. I’ve had some serious health issues that could be linked to HIT, which I think might have been caused by a serious mould infestation in my home after a very wet autumn in 2015. I suddenly developed hyperthyroid symptoms, even though I was taking the same dose of thyroid meds for my hypothyroidism that I’d been on for five years. I developed awful reflux, headaches, insomnia, etc. Worst of all, I got pulmonary issues that the docs reckon are idiopathic but I know came on suddenly (at the same time as everything else). I was tachycardic at 130bpm (at my worst) and could barely walk across the room without getting breathless. The mould in my home wasn’t visible on the walls/ceilings so I didn’t know how bad it was until about a month ago when I found it growing inside my sofa/armchair and on my mattress! That probably means my feather pillows and duvet, as well as my carpets, are full of it too. Do you think I am on the right track thinking that the mould could have triggered this? The doc has referred me to an immunologist but my appt isn’t until Jan 2017. I’ve had regular right heart catheterisations to check my arterial pressures and the only time they have gone down was in July this year, 4 months after I bought a dehumidifier! Coincidence? I don’t think so. I know I am not a client but I just want some confirmation from somebody who knows what they are talking about, that I am on the right track in getting to the bottom of what happened to me. I also need to know where to start getting help and who to get it from. Any advice would be gratefully received.

    • Mould can cause histamine type issues in people with certain genetic types. I have Chronic Inflammatory Response from mould which was due to a water damaged house. You can take a Visual Contrast Test to determine whether your body is able to detoxify mould at: If you fail the test then you can consult one of the physicians listed on that site who can determine whether that is in fact the case and help you to detox the mould from your body. I hope that helps. Trust yourself but get tested.

      • Luxie Ryder

        Hi – thanks so much for the reply. I did that test a month or so ago and failed. Can’t remember the score now. I am in the UK with limited funds, so not confident to enlist the help of someone just to have to tell them I can’t afford X,Y,Z tests. My flat is owned by a housing association and I’ve managed to get them to offer to replace my mattress, clean my furniture and fix some of the probs that lead to the mould. I am also trying to get them to move me. I figure I will know for sure then if it was making me ill. Thanks again for your help.

  • Ross

    can the mast cell response be reversed once you eliminate parasites and candida (if you have both)? how long does it take?

    • Ross it depends if the mast cell response is primarily from that. In my experience mast cell activation is ‘reversed’ or at least put into remission when all the stressors are attended to this often extend beyond parasites and candida are attended to. Eliminating parasites takes about 60 days. Eliminating candida takes about 60 days. Repairing the damage can take quite a bit longer – but the symptoms are greatly improved initially. with thanks Alison

      • Ross

        thanks Alison! i am hearing how it can take 1-2 years to eliminate candida (on Nystatin) which freaks me out since I am so underweight now and cant afford to cut out carbs completely for that length of time. so youve seen patients improve in 60 days? are you for or against complete removal of carbs?

        • Yeast is opportunistic – it moves in where other things dont occupy the space. So you can eliminate the yeast on a 60 day protocol but need to only do so after addressing parasites and bacteria all the time working on gut flora. I believe some people need carbs (especially for neurotransmitters) others dont. So the answer is bioindividual.

          • Ross

            thats another huge debate to best support commensals while on meds. Some say regular probiotics, some say spore forming strains and some say prebiotic fibers. i myself cant tolerate any fibers now and i dont do so well with the soil based probiotics like prescript assist / megaspore. in your experience what has worked best for you? so much confusing conflicting information out there