Alergias A Medicamentos

C l i n i c a l P re s e n t a t i o n s
of Food Allergy
Darlene K. Mansoor,

MD, MS,

Hemant P. Sharma,

MD, MHS*

KEYWORDS
 Food allergy  Symptoms  Classification

The clinical presentations of food allergy are diverse. In addition to symptoms of
immediate hypersensitivity, there are other more subacute or chronic ways in which
food allergy may manifest. In this article, theauthors first distinguish food allergy
from nonimmunologic adverse food reactions and then discuss the diverse clinical
presentations of food allergies as categorized by their underlying immunopathology.
DEFINITION OF FOOD ALLERGY AND DIFFERENTIAL DIAGNOSIS

Food allergies or hypersensitivities are defined as adverse immune responses to food
proteins.1 It is important to distinguish foodallergies from nonimmunologic adverse
food reactions, which are considerably more common than true food allergies.
Although 20% to 30% of the general population report food allergy in themselves or
their children, the prevalence of true food allergy is only 6% to 8% in young children
and 3% to 4% in adults.2–5 Therefore, many nonimmune adverse food reactions are
incorrectly assumed to beallergic.
Examples of nonimmunologic reactions to foods include host-specific metabolic
disorders, such as lactose intolerance, galactosemia, and alcohol intolerance. In
lactose intolerance, a deficiency in the enzyme lactase results in an inability to digest
the carbohydrate lactose found in milk and dairy products. Characteristic symptoms
include abdominal pain, bloating, gas, diarrhea, andnausea.6 Responses to pharmacologically active components or toxins in foods constitute another group of nonimmune adverse food reactions. For example, in scombroid poisoning, histaminic
chemicals found in spoiled dark-meat fishes, such as tuna, mackerel, and sardines,
result in allergic symptoms on ingestion, including flushing, urticaria, angioedema,
nausea, abdominal cramping, and diarrhea.7Although the symptoms resemble those
of an allergic reaction, the underlying mechanism of scombroid poisoning is nonimmunologic. Another example of a pharmacologically active food component causing an
adverse reaction is tyramine, found in aged cheeses and pickled fish, which can
trigger migraine headaches because of the aromatic amine content. Finally,
The authors have nothing to disclose.Division of Allergy and Immunology, Center for Cancer and Blood Disorders, Children’s
National Medical Center, 111 Michigan Avenue, North West, Washington, DC 20010, USA
* Corresponding author.
E-mail address: hsharma@cnmc.org
Pediatr Clin N Am 58 (2011) 315–326
doi:10.1016/j.pcl.2011.02.008
pediatric.theclinics.com
0031-3955/11/$ – see front matter Ó 2011 Elsevier Inc. All rights reserved.316

Mansoor & Sharma

psychological disorders, such as anorexia nervosa, food aversions, and food phobias,
may also cause nonimmunologic food reactions, as can neurologic disorders, such as
auriculotemporal syndrome (facial redness or sweating after eating tart foods) and
gustatory rhinitis (rhinorrhea after eating particularly hot or spicy foods). Box 1
summarizes the differentialdiagnosis of nonimmunologic adverse food reactions.
CLASSIFICATION OF FOOD ALLERGIES

Given that food allergies are immunologically mediated, it is helpful to conceptualize
them into 3 categories based on their underlying immunopathology: (1) IgE-mediated
reactions, (2) mixed IgE- and cell-mediated reactions, and (3) cell-mediated reactions
(Table 1). The following sections of this article discussthe clinical manifestations of the
specific food-induced allergic disorders belonging to each of these 3 broad categories.
IgE-MEDIATED FOOD ALLERGIES

IgE-mediated food allergic reactions are characterized by the acute onset of symptoms,
usually minutes to 2 hours after ingestion. The rapid time course is because of the
Box 1
Differential diagnosis of nonimmunologic adverse food reactions...