Elbany Ca, De Boissieu Da,
MD, Karila Ca, MD, Alyanakian MA,
MDb, Ponvert C, MD, PhDa, Lageix F,
MDa, and Lezmi G, MD, PhDa,c.
- Service de Pneumologie et Allergologie Pédiatriques, AP-HP, Hôpital
Universitaire Necker-Enfants Malades, Paris, France
- Laboratoire d’Immunologie, Hôpital Necker-Enfants Malades, AP-HP,
Paris, France
- Faculté de Médicine, Université Paris Descartes, Paris, France
Keywords : lysozyme, anaphylaxis, egg allergy
Lysozyme (gal d4) is a minor allergen of hen’s eggs, with sensitization
to lysozyme demonstrated in up to 35% of children with hen’s-egg
allergy1. Specific IgE (sIgE) against lysozyme is
generally not useful in clinical practice for the diagnosis of egg
allergy or to monitor its evolution. Indeed, sIgE against egg white or
ovalbumin is a better predictor of hen’s-egg allergy2.
The labelling of lysozyme in packaged food products as an egg allergen
may be misleading and its recognition may be difficult for patients, as
it appears as the additive “E1105 (lysozyme)”, “conservator
(lysozyme)”, or “lysozyme (egg protein)”. Lysozyme is also present in
numerous drugs, including antiseptics and nasal sprays. Thus,
egg-allergic patients may be
frequently unknowingly exposed to small amounts of lysozyme in various
industrial food products, including cheese, pesto sauces, and pre-packed
dishes, such as pizza, ravioli, or salads, or in drugs, without such
exposure evoking an allergic reaction3. Here, we
report an unusual case of anaphylaxis induced by the lysozyme-containing
over-the-counter-drug Lysopaine® in a nine-year-old child with hen’s-egg
allergy.
A nine-year-old poly-allergic male child developed anaphylaxis after
ingesting Lysopaine®. He was followed in our department for an
IgE-mediated hen’s egg allergy, confirmed by a positive open oral food
challenge (OFC) to baked egg, associated with sensitization to eggs
(Table 1). He is also allergic to wheat and fish, both allergies having
been confirmed by the presence of sIgE and a positive open OFC. In
addition, he has allergic rhinitis to birch pollen and has presented
with asthma and atopic dermatitis in the past. He now tolerates cow’s
milk but previously presented with an IgE-mediated cow’s milk allergy,
to which the resolution was confirmed at the age of four years by a
negative open OFC to fresh milk. At the time of the reaction, he was
following oral immunotherapy to baked egg. He was avoiding fish, wheat,
and eggs in his diet and, despite being tolerant to cow’s milk, he was
avoiding dairy products because of an aversion to such products.