Mastocytosis

And in very rare cases, mastocytosis can even appear in the form of leukemia (blood cancer). The symptoms that can occur are just as varied: for example, itching, pain, a feeling of heat, diarrhea or anxiety attacks. The diagnosis of mastocytosis is therefore not easy, even for experienced doctors. The cause of the condition is an increase and overactivity of mast cells in the body. Although there is no complete cure with medication, there are a number of effective substances that enable most sufferers to significantly reduce their symptoms.

Overview: What is mastocytosis?

Mastocytosis is a non-contagious disease that is usually benign. We distinguish between two forms:

• Cutaneous mastocytosis only affects the skin (cutaneous means: affecting the skin). It usually shows small reddish-brown spots or swellings that can itch or hurt, sometimes even blisters can develop. It used to be called urticaria pigmentosa. There are also localized forms with an accumulation of mast cells that appear similar to a birthmark (so-called mastocytomas). This form of skin disease mainly affects children and adolescents and often heals spontaneously after a while
• Systemic mastocytosis is more common in adults. It often affects the bone marrow. Internal organs such as the intestines, liver, lymph nodes and spleen can also be affected.

Both forms of mastocytosis have in common that an excess of mast cells is active in the body of those affected. These cells are formed in the bone marrow and belong to the white blood cells. They contain substances that react to pathogens and can trigger biological mechanisms. The disease is caused by a spontaneously occurring, non-inherited mutation in the mast cells, which causes them to multiply abnormally or (more rarely) grow uncontrollably (mast cell sarcoma). It is also possible that they do not adhere to their pre-programmed cell death and live too long.

Mastocytosis – frequency and age

Mastocytosis is a very rare disease. Experts estimate that in Switzerland and other European countries, fewer than ten in a million people contract the disease each year. Around two thirds of those affected by mastocytosis are children and one third are adults. Boys and girls as well as men and women are equally affected. Familial clusters are rarely found – if you suffer from mastocytosis, there are probably no other cases in your family.

Among children suffering from mastocytosis, the cutaneous form is the most common. Adults are most frequently affected by the benign (indolent) variant of systemic mastocytosis. There are also aggressive, malignant variants, but these are very rare. Such aggressive forms are usually new; it is extremely rare for a benign form to develop into a malignant form years later.

Mastocytosis: causes and risk factors

If you suffer from mastocytosis, we will not be able to say with certainty why it has affected you of all people. Your illness is not hereditary and you have not contracted it. You are probably one of the vast majority of people with mastocytosis in whom a genetic change (mutation) has occurred for no apparent reason.

Your symptoms may not appear out of the blue, but only when a certain trigger is present. There are mastocytosis sufferers who live symptom-free for years. Only when they are exposed to a certain situation do the symptoms of their illness become apparent. Trigger factors can be, for example

• Sunlight
• Cold, heat
• physical exertion
• emotional stress
• Alcohol
• certain foods or spices
• Insect bites
• Medication (e.g. anesthetics, X-ray contrast media, codeine, aspirin)

These trigger factors are by no means obligatory and are very individual: there are people with mastocytosis who tolerate physical exertion, insect bites or contrast media without any problems, while others are highly sensitive to some or all of these factors.

Mastocytosis: increased risk with other treatments

If you are planning an operation, as a person affected by mastocytosis you must inform the hospital staff of your diagnosis. In many cases, the operation can be performed without any problems. In individual cases, however, the anesthetics may cause a severe allergic reaction in you. Special medication to reduce allergic reactions as preparatory medication can prevent this.

The same applies if you are to be administered an X-ray contrast medium – in this case, also inform the doctor about your mastocytosis.

Symptoms: Mastocytosis

Mastocytosis can manifest itself in different ways in affected individuals. There are mild, moderate and very severe cases. Sometimes there is only one symptom, in other cases several symptoms occur. Which form of mastocytosis you develop depends on where and to what extent the mast cells have multiplied in your body.

The most common symptoms of cutaneous mastocytosis are brown-red patches. They often appear on the thighs, in the abdominal and chest area or in the back and pelvic area. The head and therefore also the face are usually left out. In adults, the spots are usually millimeter-sized, in children rather centimeter-sized. If you rub the spots, they usually start to itch. They often develop into swellings (wheals) after some time. The brown-red, itchy skin patches occur in around 80 percent of all mastocytosis sufferers – not just those who suffer from the isolated cutaneous (skin-related) form of mastocytosis.

Rarer symptoms are abdominal pain, nausea, vomiting and diarrhea. Headaches, joint pain and fatigue can also occur. Severe signs of illness such as shortness of breath, fever, heat attacks and circulatory collapse can also occur. Such severe symptoms occur when many mast cells are active at the same time. Psychological symptoms such as anxiety, depression, sleep problems or drowsiness can also occur.

Even rarer are the aggressive and malignant forms of mastocytosis. They do not belong to the cutaneous form, but to the systemic form of this disease. In these cases, the mast cells displace the healthy cells of organs, thereby enlarging them and hindering their work. This can be the case in the liver, spleen or lymph nodes, for example. In extreme cases, the affected organs can fail.

Cases of mastocytosis, in which there are changes in the blood count, are particularly rare. There are various manifestations here, for example the increased occurrence of certain blood cells. There is an extremely rare form of leukemia (mast cell leukemia). Symptoms in these cases often include fever, general malaise and loss of appetite and weight.

Mastocytosis: Diagnosis with us

Does your skin show the typical brown-red spots? However, these alone would not be proof of the disease. A test provides more clarity: we irritate one of the affected areas by scratching or rubbing it. If wheals then form on the skin (resulting in the so-called Darier’s sign), the diagnosis of cutaneous mastocytosis is as good as established. However, only a skin biopsy, the removal of a skin sample, is absolutely certain. If it is examined in the laboratory and an accumulation of mast cells is found, this confirms the suspicion.

However, we do not yet know which form of mastocytosis you have – the purely cutaneous form (only the skin is affected) or the systemic form (internal organs are also affected). First, we take a careful medical history, i.e. we ask about possible trigger factors or previous allergic reactions. We will also have your blood tested to determine how much of the substance tryptase it contains. Tryptase is a messenger substance that is released by mast cells. In cutaneous mastocytosis, the tryptase value is often still within the normal range, whereas in systemic mastocytosis it is usually elevated.

Recently, specialized centers, including the USZ, have also been able to search for the aforementioned mutation (c-KIT D816) in the blood; if this is detected, there is a high probability of systemic mastocytosis.

An even stronger indication that the systemic form of the disease is present is provided by taking a bone marrow sample from the pelvic bone. If the bone marrow biopsy shows an excessive number of mast cells, this is a further sign of systemic mastocytosis. Another indication: more than a quarter of the mast cells examined have an atypical shape (oval or spindle-shaped instead of round). In addition, special stains in the bone marrow can provide very differentiated information about the type of increased mast cells.

In the systemic form of mastocytosis, the liver or spleen may become enlarged. If this is suspected, an ultrasound examination of the abdomen and corresponding laboratory values are used to check this.

Mastocytosis: prevention, early detection, prognosis

There is no direct possibility of prevention. But an indirect one: If you know the trigger that causes you to develop symptoms of mastocytosis, you can avoid this triggering stimulus. Perhaps you are hypersensitive to certain foods or medications without knowing it – then you should try to identify them and avoid them.

There may be several different stimuli that play a role for you. The better you know them, the better you can try to avoid them. You will probably need patience to find these triggers – but it can be worth it. An allergological clarification is often very helpful. It is even possible that you will then live without any symptoms despite mastocytosis.

Course and prognosis of mastocytosis

If mastocytosis occurs at an early age, there is a more than 50 percent chance that the skin spots will fade or disappear completely by the age of 18. This often happens before school age, especially in isolated forms. On the other hand, systemic mastocytosis is less common in children and the signs of the disease are still present in adulthood.

If mastocytosis occurs after puberty, the symptoms do not disappear on their own in the vast majority of cases.

Very important: The vast majority of people affected by mastocytosis – more than 95 percent – have an absolutely normal life expectancy. It is shortened in less than five percent of patients suffering from an aggressive variant of systemic mastocytosis or the very rare mast cell leukemia. Around ten to 30 percent of people affected by systemic mastocytosis experience a reduction in bone density (osteopenia) or bone loss (osteoporosis) over the years.

The following applies to all mastocytosis sufferers: the disease usually progresses slowly. For example, the skin spots initially increase in size after they first appear and then do not spread any further, or they only multiply slowly. Even if your bone marrow or internal organs are affected, the course of your mastocytosis can remain stable for a long time. Progression of the symptoms cannot be completely ruled out, but is by no means inevitable.

Self-help groups

The exchange with people who are affected by the same disease can be a great support in coping with the disease. Advice on finding a suitable self-help group is available from Selbsthilfe Zürich. Self-Help Zurich and the University Hospital Zurich are cooperation partners in the national project “Health literacy thanks to self-help-friendly hospitals”.

Mastocytosis: possible treatments

Although it is not possible to cure mastocytosis completely, its symptoms can be alleviated. As already mentioned, you should first look for trigger factors yourself and avoid them if possible. Depending on your individual clinical picture, we can also administer one or more of the following active ingredients.