Introduction
Cow’s milk allergy (CMA) is defined as a reproducible adverse reaction
to cow milk protein mediated by an immunologic mechanism, involving
immunoglobulin E (IgE)-mediated, non-IgE-mediated, or mixed
mechanisms[1]. IgE-mediated reactions often occur
rapidly, typically beginning within minutes to 2 hours from the time of
ingestion[2]. Clinical manifestations of
IgE-mediated cow’s milk allergy (IMCMA) include urticaria, angioedema,
rhinitis, conjunctivitis, asthma, oral allergy syndrome,
gastrointestinal symptoms, and generalized anaphylaxis. Many children
with CMA improve before school age, but in some cases, it persists even
into adulthood[3, 4]. The current standard
treatment for CMA is strict avoidance and emergency treatment of severe
adverse reactions. However, because milk is ubiquitous in store-bought
foods, and in-home and restaurant recipes, it is especially difficult to
avoid. On the other hand, it is inevitable of accidental exposure to
cow’s milk, sometimes it can be life-threatening and has a major impact
on quality of life[5]. A strict avoidance has
negative consequences in patients such as a risk of poor nutrition,
increased levels of anxiety, and possible unjustified restrictions to
further foods, with an increased immunological risk of non-acquiring
tolerance[6]. So it needs to find some new
treatments, such as oral immunotherapy (OIT). OIT can be proposed at
different ages as an effective and safe treatment[1,
7].
OIT involves the introduction of a very small amount of cow’s milk
protein and gradual increases of the dose at predetermined intervals.
The global aim is to increase the reactive threshold of allergic
patients, and finally enable them to ingest a target quantity of
allergen without any reaction throughout the treatment
(desensitization). Many studies have showed the efficacy of OIT in
desensitization, and some of them in sustained unresponsiveness.
However, there is an ongoing debate about the safety of
OIT[7-9]. Because of the increasing interest in
this topic and emerging studies, it is important to provide an
up-to-date systematic review with ongoing updates. The main objective of
this meta-analysis is to assess the clinical efficacy and safety of OIT
in children with IMCMA as compared to a placebo treatment or milk
avoidance.