C. Range of Adverse Effects The clinical manifestations of food allergic reactions range from mild irritation to severe, life-threatening respiratory distress and shock. Specific signs and symptoms may involve the skin (e.g., pruritis, erythema, urticaria, angiodemia, eczema), eyes (e.g., conjunctivitis, periorbital swelling), nose (e.g., rhinitis, sneezing), oral cavity (e.g., swelling and itching of lips, tongue, or palate), or gastrointestinal tract (e.g., reflux, colic, abdominal pain, nausea, vomiting, diarrhea). In more severe reactions, involvement of the respiratory tract (e.g., cough, asthma, difficulty breathing, swelling around the larynx and vocal cords) and cardiovascular system (e.g., faintness, hypotension) can lead to loss of consciousness, asphyxiation, shock, or death. The term “anaphylaxis” is used to describe multisystemic severe reactions to an allergen requiring immediate medical intervention (Jackson, 2003).
Table II-1 provides a summary of the signs and symptoms that may be experienced during an allergic reaction. Allergic reactions usually occur within a few minutes to hours after ingestion of an offending food and often progress on a continuum from mild to severe, with higher doses causing more severe reactions (Sampson et al., 2005). Once exposure occurs, individuals may experience immediate numbness or pruritis at the site of contact or experience general uneasiness. These symptoms are characterized as “subjective” since they cannot be observed by others. As the effects progress, “objective” signs such as flushed skin, hives, or swelling of the lips and face may occur. These signs are often mild and short-lived. However, in some cases, they may be associated with more severe responses involving the respiratory and/or cardiovascular systems. Such responses can lead to hospitalization or death, even with appropriate medical intervention. Not all severe, or anaphylactic, reactions are necessarily preceded by milder signs and not all reactions are immediate. In some cases, anaphylactic reactions may be delayed by a few hours after the initial response (Sampson et al., 2005).
Anaphylaxis is a poorly defined condition representing a severe or multisystemic allergic reaction (Sampson et al., 2005). Allergic reactions described by objective signs involving the respiratory or cardiovascular systems would be considered severe and managed as an anaphylactic reaction by most clinicians. In some classifications, reactions involving two or more of the categories shown in Table II-1 (e.g., cutaneous, gastrointestinal, respiratory), would also be classified as anaphylaxis, if they are relatively mild. Anaphylactic “shock” denotes a consequence of anaphylaxis where heart irregularities and leakage of blood vessels leads to extreme blood volume loss (usually greater than 25% of resting blood volume) and extreme hypotension.
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