This blog focuses on my personal experience of mast cell disease and was never intended to provide information on the disease itself – there are some great websites out there that do that far better than I ever could (Mast Attack written by Scientist and systemic mastocytosis patient Lisa Klimas being one of the best). But from comments and questions I’ve received it seems there is a lot of confusion about histamine and mast cells so I’m including some simple information which I hope you find helpful.
Mast cells live in connective tissue all over our bodies, particularly the skin, gut, mouth, nose, lungs and brain. They are part of our immune system and are vital for health. We all have mast cells and they do an important job of protecting our bodies from harmful outside ‘invaders’ like germs and parasites. However, for reasons as yet unknown, mast cells can go haywire and react to things which they should consider ‘safe’ and just ignore. When this happens, the mast cells release over 30 chemicals into the bloodstream (known as de-granulation), including histamine which causes hives, itching, swelling and in some cases life-threatening anaphylaxis. Some of the other chemicals released include: serotonin & dopamine (neurotransmitters which affect mood and behaviour amongst many other functions); heparin (which thins the blood); prostaglandins and cytokines (which cause inflammation and swelling) – see more on mast cell mediators on the excellent Me & my mast cells website.
There are various types of diseases which involve mast cells:
- The most common are allergies, where the immune system over-reacts to specific foods or environmental triggers such as nuts, animal fur or pollen, causing mast cells to de-granulate and produce histamine.
- Mast cells are also implicated in Autoimmune diseases such as rheumatoid arthritis, where the immune system attacks the body itself.
- And then there are mast cell diseases which aren’t triggered by the immune system, but where the mast cells themselves become faulty.
There are so far two types of known mast cell disease:
This is a rare but recognised disease where the body contains too many mast cells and they are oddly shaped. Because of the number and shape of the mast cells they de-granulate too easily, releasing massive amounts of chemicals, including histamine, into the body.
Diagnosis includes a blood sample for a protein called Tryptase, with anything over 20 strongly indicating the disease. Many GPs can test for tryptase, or you can be referred to an immunologist or allergy specialist. If Tryptase is high other tests, like a skin or bone marrow biopsy, are needed to confirm the amount and shape of the mast cells and the type of Mastocytosis the patient has (systemic or cutaneous) – this is usually arranged by an Immunologist or Dermatologist who specializes in Mastocytosis.
There is no cure for Mastocytosis. Treatment includes H1 and H2 anti-histamine drugs (usually Zantac & Zyrtec), and mast cell stabilizing drugs such as Nalcrom (also known as Gastrocrom) or Ketotifen. However, sometimes much more powerful drugs may be needed.
Symptoms may, or may not, also be helped by following a low histamine diet and by supplementing with Vitamin C.
2. MAST CELL ACTIVATION SYNDROME
There are some people with all the symptoms of Mastocytosis but whose Tryptase levels are normal. These patients are diagnosed with Mast Cell Activation Syndrome/Disorder, a disease which has only been recognised in the past few years so most health professionals know nothing about it. In MCAD there are a normal number of mast cells and they are normal in shape, but they are over-active, producing the same chemicals as in Mastocytosis, including histamine. The mast cells can over-react in any number of perfectly normal situations: exposure to sunlight, heat and/or cold; a wide variety of foods and drugs; the skin being rubbed or pressed; being over-tired; and emotions like stress or excitement.
MCAD is much more common in people with Ehlers-Danlos Syndrome than the healthy population (recent figures suggest 1 in 10 people with EDS will also have Mast Cell Disease), possibly because mast cells live in connective tissue and of course the connective tissue in EDS is faulty.
Diagnosis is extremely hard to get as so little is known by the medical profession about MCAD and diagnostic criteria are still being agreed with the World Health Organisation. The only person to see in the UK is Dr Seneviratne at St Mary’s in London, though he isn’t funded to treat MCAD on the NHS so you will have to pay privately which can be very expensive.
Diagnosis is usually based on history and symptoms, and whether or not you respond to anti-histamine therapy, though there are tests available which can confirm mast cell activation. In America the tests available are: 24 hour urine Methylhistamine, 24 hour urine PD2, 24 hour urine Leukotriene, Chromoglanin A and Heparin. In Britain none of these tests are available, though the Doctor’s Lab in London can test for plasma histamine, and spot urine histamine:creatinine ratio (Dr Seneviratne will refer you). If you have the money he can also send samples to America to be tested for leukotrienes. These are all very specialist tests and the samples must be handled in very specific ways (eg frozen immediately) in order to obtain reliable results.
Treatment is the same as for Mastocytosis, eg anti-histamines, mast cell stabilizing drugs and low histamine diet, though again there is no cure.
A list of symptoms for mast cell diseases can be found on the Mastocytosis Society of Canada’s website or if you suspect you may have mast cell disease have a look at a list of suggestive symptoms on the Oregon Ehlers-Danlos support group page.
What’s in a name?
There are two terms used online for mast cell disease: Mast Cell Activation Syndrome (MCAS) and Mast Cell Activation Disorder (MCAD). Some people, even some doctors and researchers, use the term interchangeably to describe Mast Cell Activation Syndrome. However, if you wan to be technically accurate MCAD is an umbrella term for all mast cell diseases, so if you have Mastocytosis you have MCAD and if you have Mast Cell Activation Syndrome you also have MCAD, and if you have Cutaneous Mastocytosis you too have MCAD, because MCAD is an umbrella term for all the different types of mast cell diseases. Mast Cell Activation Syndrome is, therefore, a type of MCAD.
Why, then, do I use the term MCAD on my blog and not MCAS? The reason being I haven’t had other mast cell diseases ruled out, so although my Consultant said I “probably” have MCAS until I know for sure I don’t have another type of mast cell disease I use the term MCAD to cover all my bases
Histamine Intolerance (known as HIT) isn’t a mast cell disease but can share many symptoms with both Mastocytosis and MCAD. HIT involves low levels of certain enzymes in the stomach, the most known about is an enzyme called Diamine Oxydase (DAO). Everyone needs histamine to digest food, and histamine is also present in the foods we eat (though some foods are higher in histamine than others). When DAO is low, histamine released during digestion and also from the food we eat isn’t dealt with effectively, causing histamine toxicity to build up throughout the body.
Diagnosis is, again, very difficult to obtain and certainly not available within the NHS in the UK. Dr Seneviratne is the only Consultant I know in the UK who diagnoses HIT. He will refer you to the private Doctor’s Lab in London to have your DAO levels tested.
Most people with HIT manage their symptoms solely with a low histamine diet, though there are supplements, eg, DAOSIN, which claim to help increase levels of DAO in the gut (do bear in mind, however, that the side effects and long term effects of taking DAOSIN aren’t known). Anti-histamine drugs, particularly H2 blockers which control stomach acid, can also be useful.
I wrote a research paper on mast cells and how they could be implicated in M.E.. See The Canary blog post (which also contains some general info on mast cell activation) and follow up post The Canary Q&A.
Please also see my Links & Resources page for further information on Mast Cell Disease.
Tags: Mast Cell Disease, Mastocytosis, Mast Cell Activation Disorder, Histamine Intolerance, diagnosis, treatment, referral