Food Allergy
The child described in the vignette has classic symptoms of
anaphylaxis: respiratory difficulties,
urticaria,
and generalized discomfort. Many patients who experience anaphylaxis
describe an impending sense of doom.
Studies have demonstrated that patients
who do not have an urticarial
rash are at much higher risk of death than those who have one.
The most likely cause of this child's anaphylaxis is a food allergy. Because she
has been receiving amoxicillin for several days, it is unlikely that the
reaction is due to that medication. The history of disliking eggs and usually
not eating them provides a clue to the potential food allergy;
many children who have a food allergy
will refuse to eat the offending food long before the food is identified as an
allergen.
The primary cause of anaphylaxis in
children is foods; bee stings and drugs are much less likely causative
agents. The primary food
allergens in infants and toddlers are eggs, milk, wheat, and soy. Among older
children, shellfish, fish, nuts, and peanuts are also common triggers.
The mainstay of therapy for anaphylaxis is administration of
subcutaneous epinephrine. Studies
have demonstrated that patients in whom administration of the initial
epinephrine is delayed have a higher mortality rate than those who are promptly
given epinephrine. Patients usually have
symptoms within 10 minutes of ingestion, but may not develop all the symptoms of
anaphylaxis for up to 2 hours after the ingestion. Accordingly,
epinephrine should be given at the first
sign of symptoms, and the child should be transferred promptly to a
medical facility.
Food poisoning does not cause respiratory difficulties or urticaria. Serum
sickness can cause urticaria and general discomfort, but it is not abrupt in
onset and does not have respiratory symptoms. Viral urticaria is not seen
acutely in a previously well child.
References:
deShazo RD, Kemp SF. Allergic reactions to drugs and biologic agents.
JAMA. 1997;278:1895-1906
Lieberman P. Anaphylaxis and anaphylactoid reactions. In: Middleton E
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Allergy: Principles and Practice. 5th ed. St Louis, Mo: Mosby-Year
Book, Inc; 1998:1079-1092
Sampson HA, Mendelson L, Rosen JP. Fatal and near-fatal anaphylactic
reactions to food in children and adolescents. N Engl J Med.
1992;327:380-384
Sampson HA. Adverse reactions to foods. In: Middleton E Jr, Reed CE,
Ellis EF, Adkinson NF Jr, Yunginger JW, Busse WW, eds. Allergy:
Principles and Practice. 5th ed. St Louis, Mo: Mosby-Year Book, Inc;
1998:1162-1182
Sampson HA. Food allergy. JAMA. 1997;278:1888-1894