1. Egg Allergy Important food allergy in children Starts early in life
Often resolved by school age
Symptoms:
atopic dermatitis, urticaria, asthma, anaphylaxis
Sensitization may predict atopic disease later in life
Prevalence: 1-2%
Boiled/heated egg may be tolerated

2. Doctor's challenges Is there a risk for severe reactions?
Could the patient tolerate cooked egg?
Is the allergy likely to be persistent?
How should the patient best be managed?
Who needs strict avoidance?
Who needs emergency medication?

3. Common clinical practice
Patient
Previous
At 7 months
Anamnesis
At 2 years
SPT to egg
Diagnosis
Advice
At 5 years
sIgE to egg
Food challenge
Elin, 5 years
Eczema
Urticaria, asthma +5
Egg allergy
Avoid egg
25 kUA/l
No symptoms
Tolerant to egg
Nour, 5 years
Eczema
Urticaria, asthma +4
Egg allergy
Avoid egg
20 kUA/l
Urticaria, cough, rhinitis

4. Egg white components

5. Egg white components

6. Main egg allergen components
Gal d 2
Ovomucoid – Gal d 1
Ovalbumin – Gal d 2
Ovotransferrin – Gal d 3
Lysozyme – Gal d 4
Gal d 3
Gal d 1
Gal d 4
Latin name: Gal d – Gallus domesticus

7. Ovomucoid - Gal d 1 The dominant egg white component
11 % of egg white content
Highly allergenic
Stable to heat and
enzymatic digestion
Gal d 1

8. Ovomucoid and tolerance
Boiled egg may be tolerated if Ovomucoid-IgE levels are low
Persistent egg allergy is seen in patients with high Ovomucoid-IgE levels
The stability of Ovomucoid reflects the clinical picture

9. Characteristics of main egg white components

10. Using components in clinical practice
Patient
Previous
At 7 months
Anamnesis
At 2 years
SPT to egg
sIgE to egg
sIgE to Ovomucoid
Diagnosis
Advice
Elin, 5 years
Eczema
Urticaria, asthma +5
25 kUA/l
0.4 kUA/l
Tolerance likely
Low risk for reactions
Try cooked egg
Nour, 5 years
Eczema
Urticaria, asthma +4
20 kUA/l
12 kUA/l
Egg allergy
Avoid egg
Improved diagnoses and altered advice

11. What does Molecular Allergology add?
Sensitization to Ovomucoid indicates:
Risk for reaction to all forms of egg
Persistent egg allergy
Risk for systemic reactions to egg
Absence of sensitization to Ovomucoid indicates:
Tolerance to cooked egg

12. Extra slides

13. Ovomucoid – clinical utility
“-Quantification of ovomucoid antibodies could be useful in guiding the physician in the decision whether to perform a challenge or not”

14. Ovomucoid – clinical utility
“-For prediction of reaction to heated egg white, ovomucoid was superior” (to egg white) 14

15. Ovalbumin – Gal d 2 The most abundant allergen in egg white (54%)
Heat labile
Highly allergenic

16. Conalbumin = Ovotransferrin
Conalbumin – Gal d 3
12% of egg white protein
Heat labile
Present also in egg yolk
Conalbumin = Ovotransferrin

17. Lysozyme – Gal d 4 Minor allergen 3.5% of egg white protein
Used as preservative/additive
Occupational allergen (food and pharmaceutical industries)