Aspirin provocation of patients with Systemic Mastocytosis

Systemic mastocytosis (SM) is a myeloproliferative disease in which aberrant
mast cells accumulate. Patients with SM experience more anaphylaxis than
healthy persons because of the large amount of mast cells. For this reason, the
use of certain medications that theoretically could trigger mast cell
degranulation is discouraged in SM patients. Among these medications are
radiologic contrast media, anaesthetics, opioid analgesics and nonsteroidal
anti-inflammatory drugs (NSAID*s). However, SM patients could benefit from some
of these drugs in their daily life. Acetylsalicyl acid (ASA) is a proven remedy
for flushing in some patients. Moreover, since osteoporosis is a frequent
complication of SM, they are more often in need of analgesics due to fractures
etc. Officially, the only *allowed* analgesic is acetaminophen. For these
reasons, it would be of great importance to explore the real prevalence and
severity of aspirin-induced anaphylaxis in SM patients. Aspirin can be used as
a model for all NSAID*s.
Please see the complete procotol for a more extensive review of the literature.

To determine the prevalence and severity of ASA-related allergic reaction in SM
patients.

Double-blind, placebo-controlled intervention study.

Provocation with ASA
1 day of 4 hours, patients will receive three placebo tablets
1 day of 4 hours, subjects will receive ASA in three ascending dosages

Patients will have to spend 2 separate days of 4 hours in the hospital. During
these days, we will collect blood and urine samples on two occasions.
Questionnaires and minor physical examination will be performed every hour to
screen for anaphylactic symptoms.
We do not expect the patients to experience any other discomfort. However, they
will be at theoretical risk for anaphylaxis during the provocation test. We
expect a low incidence and minor severity of anaphylactic symptoms. However, a
medical doctor and trained nursing staff will be available at all times to
monitor symptoms and treat anaphylaxis if necessary. Facilities for admittance
of patients for longer observation is available if necessary.
As argumented before in this protocol, participation in this study has direct
benefit for subjects; they will be informerd whether they can safely use
NSAID's in the future. ASA can be used to treat flushing, a symptom that has
large influence on their quality of life. Secondly, up to 40% of SM patients
develop osteoporosis which can be accompanied by pain, which can be treated
with NSAID's.