(Mast cell activation disorders, SAMA)

Relatively new entity (first published in 2007). Immune pathology in which mast cells  inappropriately and excessively release the chemical mediators contained in their granules [histamine, heparin, prostaglandins, Platelet Activating Factor, angiotensin-converting enzyme, leukotrienes, proteolytic enzymes, cytokines, TNF alpha]. This causes chronic and/or recurrent symptoms, including  anaphylactic shock or similar conditions. Unlike  mastocytosis, where patients have an increased number of mast cells, patients with SAMA have a normal number of these cells, but these are defined as "hyperreactive". 

The causes are:

• idiopathic
• congenital (so-called clonal form) following a mutation in the KIT gene. The stem cell factor or  c-Kit ligand is an essential growth factor for the development and differentiation of mast cells from hematopoietic progenitors.
• hereditary alpha-tryptasemia syndrome (see this term), causing a multiplication of the TPSAB1 gene  coding for alpha-tryptase
• secondary to an allergy (bite of hymenoptera insect for example),
• secondary to an autoimmune pathology.

The main symptoms can fluctuate in their type, severity and duration. Many manifestations and symptoms are the same as those of mastocytosis.

Common symptoms are:

• Dermatological
• hot flushes
• skin redness
• chronic itching
• recurrent urticaria

• Cardiovascular
• dizziness, vertigo, syncope
• blood pressure drops, postural tachycardia

• Gastrointestinal
• diarrhea or constipation, cramps, intestinal discomfort, bloating, reflux
• nausea, vomiting

• Psychological and Neurological
• headaches, migraines
• concomitant with the release of mast cell mediators in the brain: panic attacks, depression, aggressiveness,

• Respiratory
• nasal congestion, coughing, wheezing, asthma,

• Urological
• dysuria, polyuria, nocturia

• Constitutional
• general fatigue and malaise
• various and varied intolerances to foods, certain pharmaceutical and chemical products (such as medicines, perfumes)
• disorders of the body temperature regulation (excessive sensations of heat or cold)

• Musculoskeletal
• Osteoporosis  and  osteopenia,  which is common in mastocytosis, is not found in idiopathic SAMA but appears to be associated with clonal SAMA
• muscle and joint pain

• Anaphylactic or anaphylactoid shock .

Symptoms can be caused or aggravated by triggers, which vary widely and are specific.

Common triggering factors are:

• certain foods and beverages (especially alcohol, and foods with a high histamine content)
• temperature changes, shower
• odors, including perfumes or smoke
• exercise or physical exertion
• emotional stress
• drugs: non-steroidal anti-inflammatory drugs, codeine, ...

Treatment: mainly symptomatic

• mast cell stabilizers, including sodium cromoglycate
• H1 anti-histamines, such as cetirizine or ketotifen
• H2 antihistamines, such as famotidine
• anti-leukotrienes, such as montelukast
• avoid triggers specific to the patient.

Anesthetic implications:

increased risk of anaphylactic reaction; although no cases of anesthetic management have been described, it is sound to apply the same recommendations as in case of mastocytosis (see this term).

References :

Updated: September 2021