What are the side effects of egg lysozyme?

December 21, 2025 •

3 min read

Lysozyme, a natural enzyme with antibacterial properties found abundantly in hen egg whites, is commonly used as a food preservative. However, for a small percentage of the population, specifically those with an egg allergy, this additive can trigger adverse reactions ranging from mild rashes to severe, life-threatening anaphylaxis.

Quick Summary

Lysozyme, an egg white enzyme used as a food preservative (E1105), can cause severe allergic reactions in individuals with egg allergies. Adverse effects include skin rashes, respiratory distress, and anaphylaxis, necessitating careful label reading and consultation for sensitive individuals.

Key Points

Allergic Reactions: The main side effect of egg lysozyme is triggering allergic responses, which can include skin rashes, hives, and swelling, particularly in individuals with pre-existing egg allergies.
Anaphylaxis Risk: For highly sensitive individuals, exposure to egg lysozyme can result in anaphylaxis, a severe and potentially life-threatening allergic reaction affecting breathing and blood pressure.
Respiratory Symptoms: Less severe allergic reactions may include respiratory issues such as sneezing, a runny nose, wheezing, and coughing.
Digestive Upset: Gastrointestinal side effects like abdominal cramps, nausea, and vomiting can also occur in response to egg lysozyme exposure.
Mandatory Labeling: Due to its allergenic properties, egg-derived lysozyme (E1105) requires clear labeling on food products in many countries to inform consumers with egg allergies.
Non-Allergic Alternatives: For medical or sensitive applications, non-egg sources of lysozyme exist, offering a low-immunogenic option for individuals with egg allergies.

Egg Lysozyme and Its Allergenic Potential

Egg lysozyme (E1105) is a naturally occurring enzyme derived from hen egg whites, prized in the food industry for its antimicrobial properties. It is particularly effective against Gram-positive bacteria, which helps extend the shelf life of various products. Despite being widely considered safe for the general population, its origin from eggs makes it a known allergen for sensitive individuals. This allergenic potential is the primary concern regarding its side effects and has led to mandatory labeling in many countries to protect consumers.

Allergic Reactions: The Primary Side Effect

For those with a pre-existing egg allergy, exposure to egg lysozyme can cause a range of allergic symptoms. These reactions are not a sign of toxicity in the traditional sense but rather an immune system overreaction to the egg protein. The severity can vary significantly among individuals, from mild and localized symptoms to severe systemic responses.

Common Allergic Symptoms

Skin reactions: This is one of the most frequently reported side effects. Symptoms include urticaria (hives), skin rashes, swelling, and eczema flare-ups.
Respiratory issues: Inhalation or ingestion can cause allergic rhinitis, leading to symptoms like a runny nose, stuffiness, and sneezing. More severe cases may involve asthma-like symptoms, including wheezing, coughing, and shortness of breath.
Gastrointestinal problems: Digestive upset can manifest as abdominal cramps, nausea, vomiting, or diarrhea.

Anaphylaxis: A Life-Threatening Risk

The most serious and life-threatening side effect of egg lysozyme for highly sensitive individuals is anaphylaxis. This severe allergic reaction is a medical emergency and can occur rapidly after exposure. Symptoms of anaphylaxis can include:

Tightening of the airways and a swollen throat, making it difficult to breathe.
A sudden and severe drop in blood pressure (shock), which can cause dizziness or fainting.
A rapid heart rate.

Healthcare professionals advise anyone at risk to carry an epinephrine auto-injector and seek immediate medical attention if anaphylaxis symptoms occur.

Other Potential Reactions and Considerations

While allergic reactions are the main risk, other potential side effects associated with lysozyme-containing products or supplements have been reported, although they may not be directly tied to the egg-derived version or food additive use. Some of these are observed in specific clinical contexts and may include:

Gastrointestinal discomfort
Exacerbation of autoimmune conditions, in theory
Drug interactions
Bacterial resistance, in cases of long-term use

These are important considerations, especially when dealing with lysozyme in a medicinal or high-concentration context, but the primary concern for consumers of egg-derived lysozyme is the allergic response.

Comparison of Egg Lysozyme and Non-Egg Lysozyme

Not all lysozyme is derived from eggs, and the potential for side effects differs significantly based on the source. Below is a comparison of key aspects.


Feature	Egg Lysozyme (Hen Egg White)	Non-Egg Lysozyme (e.g., microbial, human)
Source	Hen egg white	Bacteria, yeast, plants, human sources
Allergenicity	Known allergen due to egg protein content	Considered low immunogenic and hypoallergenic
Application	Food preservative (E1105) in cheese, wine, and other products	Used in pharmaceuticals, specialized foods, and cosmetics
Regulation	Requires specific labeling in many regions for allergen status	Generally safer for egg-allergic individuals, depending on source purity
Side Effects	Primarily allergic reactions for sensitive individuals	Different side effects depending on application and source, but no egg-related allergy risk

Conclusion

In summary, the primary side effect of egg lysozyme is its potential to trigger allergic reactions in individuals with an egg allergy. While a harmless and beneficial antimicrobial for most people, its presence in foods like cheese and wine requires clear labeling to prevent adverse events in a susceptible population. For those with known egg hypersensitivity, vigilance in reading food labels is crucial. Consultation with a healthcare provider is recommended for anyone with concerns about lysozyme or egg-containing products. Research continues into non-allergenic lysozyme alternatives to minimize this risk.

Frequently Asked Questions

Egg lysozyme is a natural enzyme with antibacterial properties derived from hen egg white and used as a food preservative (E1105). It is commonly added to certain cheeses, wine, and other processed foods to inhibit bacterial growth and extend shelf life.

Only individuals with a pre-existing egg allergy or hypersensitivity are at significant risk of experiencing side effects from egg lysozyme. It is a known allergen derived from egg protein.

Common allergic symptoms include skin reactions like hives, rashes, and swelling, as well as respiratory issues such as sneezing and wheezing, and digestive problems like nausea and cramping.

Yes, for highly sensitive individuals, egg lysozyme can cause anaphylaxis, a severe, life-threatening allergic reaction. Symptoms can include airway tightening, a rapid heart rate, and a dangerous drop in blood pressure.

You can avoid egg lysozyme by carefully reading food labels and looking for "egg white lysozyme" or the food additive code E1105 in the ingredient list. Since it is derived from eggs, its presence must be declared.

Lysozyme hydrochloride is a type of lysozyme salt, often derived from egg whites, and used in some pharmaceutical products. The potential for allergic reactions from egg-derived lysozyme remains the same regardless of its form.

If you suspect a reaction, stop consuming the product and consult with a healthcare professional or allergist. For severe symptoms like trouble breathing, seek emergency medical care immediately.