Tolerance of camel*s milk and mare*s milk in cow*s milk protein allergy.

Cow*s milk protein allergy (CMA) is a common problem in young infants, but can
also occur in older children and adults. Camel*s milk and mare*s milk proteins
differ considerably from those in cow*s milk. Therefore they might be tolerated
by patients with CMA, as has been shown in a few small studies.

Primary: To establish the tolerance of camel*s milk and mare*s milk in
standardized food provocation tests in patients with double-blind
placebo-controlled provocation (DBPCP) proven CMA >=3 years of age. Secondary:
To determine the minimum eliciting dose of camel*s milk and mare*s milk in CMA
patients who do not tolerate these milk(s) in standardized food provocation
tests; to investigate medium-term (4 weeks) and long-term (6-12 months)
tolerance of camel*s milk and mare*s milk in CMA patients who do tolerate these
milk(s) in standardized food provocation tests; to determine the titer and
affinity of specific IgE to cow*s milk, and the titer and affinity of specific
IgE to camel*s milk and mare*s milk before introduction, and after 4 weeks of
daily ingestion in the CMA patients who tolerate these milk(s) in standardized
food provocation tests. The patients'experience with the consumption of these
milks will be analysed in a short questionnaire.

Randomized cross-over intervention trial.

Participants are randomized to receive increasing doses of either camel*s milk
or mare*s milk in a standardized provocation test. One to four weeks later the
participants who first received camel*s milk, receive mare*s milk, or the
reverse. Participants who did not show allergic reactions to one milk will
consume that milk daily for four weeks; participants who did not show allergic
reactions to both milks will be randomized to receive camel*s milk or mare*s
milk daily during four weeks, and the other milk during the four weeks
thereafter. If no allergic symptoms occur during those four weeks, participants
are advised that they can go on consuming this milk if they want to. At 6-12
months after study entry, participants who had been advised they could go on
consuming one or both milks will be asked to answer a questionnaire on their
experiences with these milks.

Patients who should be considered as high-risk for DBPCP are excluded from
participation. A maximum of five study visits take place (at inclusion, during
the 2 provocation tests for camel*s milk and mare*s milk in the day care
hospital, and - if applicable - after the four weeks of daily camel*s milk and
mare*s milk consumption). Venepuncture is performed 0-3 times, depending on the
presence of left-over material before the study, and the reactions in the
provocation tests (when both are positive, the study stops). A diary is
completed daily to record symptoms during 2-10 weeks.