Mastocytosis, what is it? Causes, Symptoms and Treatment

Mastocytosis is a disease characterized by the presence in too large numbers of a kind of white blood cells in the tissues, the mast cells. These can give manifestations on the skin but also in the deep organs and generalized reactions sometimes formidable.

Definition of mastocytosis

Mastocytosis is a rare disease characterized by an excess of mast cells in the skin and / or other organs.

Mast cells are white blood cells that play a role in inflammation and allergy because they deliver mediators such as heparin, histamine, cytokines (such as TNFα) into the tissues … the tissues, dilate the blood vessels …

The clinical manifestations of mastocytosis are related, on the one hand, to the accumulation of mast cells in the tissues and, on the other hand, to the effects of the mediators that they release, which are responsible for inflammatory manifestations and allergy.

These events are classified according to the affected organs:

Cutaneous mastocytosis: pigmentary urticaria, dermographism, redness
Systemic mastocytosis: blood manifestations (anemia, increase or decrease of white blood cells, increase or decrease of platelets, malignant diseases of the blood …), neurological manifestations (headaches, syncope, vertigo, convulsions, anxiety, depression, dementia .. .), cardiovascular manifestations (palpitations, hypotension, etc.), respiratory involvement such as interstitial fibrosis or laryngeal lesions leading to respiratory problems, especially difficulty breathing …
Gastrointestinal mastitis: abdominal pain, diarrhea, nausea and vomiting …
Bone mastitis: bone, joint pain

Causes of mastocytosis

Mutations of the c-Kit gene located on chromosome 4 are found in many mastocytoses. These mutations cause the production of protein Kit that stimulates proliferation of mast cells.

Who is affected by mastocytosis?

Mastocytosis is a disease that can occur at any age, with no predisposition for sex.

Diagnosis of mastocytosis

The diagnosis of mastocytosis requires a biopsy of the skin (on an area not previously traumatized to prevent degranulation of mast cells that would make their recognition more difficult and without epinephrine in the local anesthetic or after cold anesthesia) in order to evidence of a mast cell infiltrate in the dermis whose density is greater than 15 cells per field at magnification 40.

The doctor may ask for a tryptase blood test: the normal level is less than 5 ng / ml, patients with cutaneous mastocytosis often have a level below 20 ng / ml, whereas those with systemic mastocytosis often have a rate greater than 20 ng / ml. In addition, the presence of a level greater than 75 ng / ml, would be systematically associated with the presence of the disease.

Evolution and possible complications of mastocytosis

Mastocytosis of the skin evolves by congestive flares with redness and plaque swelling.

In profuse deep or cutaneous mastocytosis, the manifestations can be serious (respiratory disorders, articular osteo involvement …).

In children, mastocytosis is often benign and often regresses in a few years.

In adults, however, there are often fears of systemic and reactive damage or even progression to malignant diseases:

Myeloproliferative or myelodysplastic syndromes (lymphomas, acute or chronic leukemias …).
aggressive mastocytosis, gradually invading all organs
Mast cell leukemia: fortunately exceptional, it is the malignant form of mastocytosis invading bone marrow and blood.

Symptoms of mastocytosis

Mastocytosis of the skin

Pigment urticaria is the most common form of skin manifestations of mastocytosis, causing small swellings of red-brown skin, the friction of which increases swelling and redness, especially in children (this is the sign of Darier). Urticaria pigmentosa disappears spontaneously at puberty in more than 50% of cases.
Mastocytomas are more common in infants: they are balls embedded in pink-brown skin, the friction of which accentuates the swelling and reddening (sign of Darier). Mastocytomas have a good prognosis and usually resolve spontaneously in a few years.
Telangiectasia macularis eruptiva perstans is a rare form of mastocytosis occurring in adults, causing small red patches covered with telangiectasia (small red-purplish vessels) on the trunk, often accompanied by deep signs.

Deep mastocytosis

Many organs can be invaded by mast cells or the target of manifestations related to mast cells, most often in addition to skin disorders (urticaria pigmentosa, diffuse cutaneous mastocytosis …).

Blood mast cell disease: anemia, increase or decrease of white blood cells, increase or decrease of platelets, malignant diseases of the blood …
Neurological mastocytosis: headache, syncope, vertigo, seizures, anxiety, depression, dementia …
Cardiorespiratory mastocytosis: palpitations, hypotension, interstitial fibrosis, laryngeal involvement …
Gastrointestinal mastitis: abdominal pain, diarrhea, nausea and vomiting …
Bone mastitis: bone, joint pain

Reactions

These are manifestations related to the release of mediators by mast cells under the influence of external factors, most often

drugs (anesthetics of the family of curare or opiates, aspirin, anti-inflammatories, codeine, morphine, polymyxin B, hydralazine, amphotericin B, quinine, scopolamine, reserpine, pilocarpine, macromolecules …)
food (peanuts, citrus, fish and shellfish, fermented cheeses, fermented and alcoholic beverages, smoked foods, tomatoes, spinach, bananas, spices, strawberries …),
physical (local traumatisms and friction, stress and emotions, temperature variation during baths, or efforts, bites of snakes or bites of Hymenoptera, surgical interventions …)

They are type of

congestive attacks of cutaneous lesions,
itching,
dermographism (when lightly rubbing the skin, it swells and grows on the rubbed areas, you can even write or draw on the skin)
general signs (headache, redness, digestive pain, diarrhea, nausea, palpitations, hypotension or even cardiovascular shock, breathing difficulties …).

Risk factors for Mastocytosis

Mastocytosis is a rare but non-exceptional disease that occurs most often without sex predisposition at any age.

The opinion experts

The prognosis is very different depending on the age and organs affected. The mastocytosis of the child, often very anxiety-provoking for the parents, is fortunately generally benign, confined to the skin and spontaneously regressive, whereas the mastocytosis of the adult is often accompanied by deep signs.

The treatment of mastocytosis is poorly coded and relies more on experience than on high-level scientific studies. In addition to treatment, preventive measures of congestive manifestations must always be well known to the patient and those around him.

Prevention

Mastocytosis cannot be prevented.

However, the triggering factors for congestive

Physical factors

Local trauma and friction
Stress and emotions
Variation of temperature (baths, efforts)
Bites of snakes or bites of Hymenoptera
Surgical interventions

Food

Peanuts, citrus fruits, fish and crustaceans, fermented cheeses, fermented and alcoholic beverages, smoked foods, tomatoes, spinach, bananas, spices, strawberries …

pharmaceuticals

Anesthetics of the curare family or opiates, aspirin, anti-inflammatories, codeine, morphine, polymyxin B, hydralazine, amphotericin B, quinine, scopolamine, reserpine, pilocarpine, macromolecules … Moreover, beta-blockers contraindicated because they decrease the effectiveness of adrenaline

Treatments of Mastocytosis

The treatment of mastocytosis consists of preventing the reaction manifestations and treating them.

Prevention of reaction thrusts

Limitation of physical factors

rubbing of the skin, especially when washing infants or children;
burns or local trauma
bites of Hymenoptera (bees, wasps …)

Avoid histamine-depleting foods

Peanuts, citrus fruits, fish and crustaceans, fermented cheeses, fermented and alcoholic beverages, smoked foods, tomatoes, spinach, bananas, spices, strawberries …

Avoid certain drugs

general anesthesia is often the cause of severe reactions. It is therefore always necessary to prevent the anesthesiologist who will avoid the curares and the opiates and will prescribe antihistamine before the intervention.
in the case of injection of iodinated contrast material before an X-ray or CT scan, antihistamines should also be prescribed
the other drugs against indicated are: aspirin, anti-inflammatories, codeine, morphine, polymyxin B, hydralazine, amphotericin B, quinine, scopolamine, reserpine, pilocarpine, macromolecules … and beta-blockers (by diminution of the efficiency of the adrenaline)

Treatment of reaction thrusts

Anti histamines

Antihistamines block histamine receptors, one of the mediators released by mast cells. They reduce the allergic symptoms (itching, swelling of the skin …) but do not modify the mast cell proliferation.

Anti histamine H1 (Aerius (desloratadine), Clarityne (loratadine), Kestin , Telfast , Tinset , Virlix (cetirizine), Xyzall (levocetirizine), Zyrtec (cetirizine) …) are often associated with anti-H2 (ranitidine, famotidine, cimetidine)

Anti degranulants

These are molecules that limit mast cell degranulation (disodium cromoglycate and ketotifen)

Shock

The occurrence of anaphylactic shock is based on emergency epinephrine injection.

Treatment of mastocytomas in small numbers

Single lesion

In case of solitary mastocytoma, surgical excision is proposed in case of functional discomfort.

Pigment urticaria

Cream with cortisone: it is used mainly on the urticaria pigmentosa
Ultra Violets: the doctor delivers Ultra-Violets in the cabin three times a week (UV therapy) because UV decreases the number of mast cells and their synthesis of mediators.