Sports Medicine: Just the Facts

226 SECTION 3 • MEDICAL PROBLEMS IN THE ATHLETE

ANAPHYLACTIC AND
ANAPHYLACTOID REACTIONS

PATHOPHYSIOLOGY

•Anaphylaxis is an acute, life-threatening, systemic
reaction mediated through IgE antibodies and their
receptors. It requires previous sensitization and subse-
quent reexposure to an allergen.

• Anaphylactoid reactions are clinically indistin-
  guishable from true anaphylaxis. Both are caused by
  massive release of potent chemical mediators from
  mast cells and basophils. The differences are: ana-
  phylactoid reactions are not mediated by IgE anti-
  bodies, they do not require prior sensitization, and
  they are less commonly associated with severe
  hypotension and cardiovascular collapse. Both are
  managed with the same treatment measures dis-
  cussed here.
  •Anaphylaxis includes cutaneous signs or symptoms
  accompanied by obstructive respiratory symptoms
  and/or hemodynamic changes. Additional features
  include gastrointestinal complaints and experienc-
  ing a “sense of impending doom” (see Table 37-6).

The onset of symptoms typically begins seconds to

minutes after the inciting cause. More rarely, symp-

toms may be delayed for up to 2 h.

• Approximately half of cases have a uniphasic
  course with abrupt, severe onset, and death within
  minutes despite treatment. Up to 20% of cases have
  a biphasic presentation. After the acute stage and a
  1–8 h asymptomatic period, a late phase reaction
  ensues with recurrence of severe symptoms. The
  late phase symptoms can be protracted, persisting
  for several hours in 28% of individuals (Kemp,
  2001).

EVALUATION

• The diagnosis of anaphylaxis is affected by variability
  in the standard case definition. Obtaining as much
  information from the affected athlete and any wit-
  nesses will define the time course, severity of the
  reaction, and the potential cause.
  •Anaphylaxis triggers include: food, medications, and
  insect stings (see Table 37-7). Any food exposure prior
  to the onset of symptoms should be documented. Of
  special concern would be exposure to the most
  common food allergens, which include eggs, peanut,
  cow’s milk, nuts, fish, soy, shellfish, and wheat.
  Several medications have been known to cause ana-
  phylaxis with the most common being beta-lactam
  antibiotics. Documenting exposure to prescription
  medications as well as over-the-counter medications
  and supplements is important. Bee-sting sensitivity

TABLE 37-6 Symptoms and Signs of Anaphylaxis

Psychologic

“Sense of impending doom”

Cutaneous

Tingling/Pruritus

Generalized erythema

Urticaria

Angioedema

Upper Airway

Nasal Congestion
Rhinorrhea
Sneezing
Globus sensation
Throat tightness
Dysphonia
Dysphagia
Lower Airway

Dyspnea

Wheezing

Cough

Cardiovascular

Lightheadedness

Syncope

Palpitations

Shock

Gastrointestinal

Abdominal cramps

Bloating

Nausea/Vomiting

TABLE 37-7 Causes of Anaphylaxis

Idiopathic

Medications

Antibiotics

IV and local anesthetics

Aspirin/NSAIDs

Chemotherapeutic agents

Opiates

Vaccines

Allergy immunotherapy sera

Radiographic contrast media

Blood products

Latex

Hymenoptera envenomation

Foods

Eggs

Peanut

Cow’s milk

Nuts

Seafood

Soy

Wheat

Exercise