Anaphylaxis (Pediatric) Disease Background

Introduction

Anaphylaxis is a serious generalized or systemic hypersensitivity reaction that is rapid in onset and potentially fatal. 

Anaphylaxis (Pediatric)_Disease Background

Epidemiology

It is estimated that the incidence of anaphylaxis in children ranges from 1 to 761 per 100,000 person-years, with a risk of recurrence of reactions as much as 26.5-54.0%. Current data show that the incidence of anaphylaxis has increased, mainly due to the increases of food allergies in infants and children. Fortunately, despite the noted increases in incidence and hospitalizations secondary to anaphylaxis, the mortality remains low, 0.05-0.51 per million people per year for drugs, 0.03-0.32 for food, and 0.09-0.13 for venom induced anaphylaxis.  

Though majority of reports of anaphylaxis are from Western countries, studies in Asia show that its incidence in this region is also increasing. In Korea, the incidence of childhood anaphylaxis rose from 6 in 2008 to 22 per 100,00 person-years in 2014, quadrupling in young children aged 0-9 years old. While in Taiwan, incidence of anaphylaxis grew at an average of 5% annually from 2001 to 2013.  

Pathophysiology

Anaphylaxis involves immunological response with IgE, high-affinity IgE receptors, mast cells, basophils, release of cytokines, chemokines, and chemical mediators of inflammation (eg histamine and tryptase). IgG-mediated anaphylaxis has been reported in humans after administration of dextran or monoclonal antibodies. Non-immunological mechanisms are also involved and termed as non-allergic anaphylaxis or anaphylactoid reaction. This is relatively uncommon in children. 

Etiology

Common Causes  

Food allergy is the most common cause in the community setting. Common allergens include cow’s milk, egg white, shellfish, peanuts, tree nuts, and wheat. Medications such as penicillins, beta-lactams, cephalosporins, nonsteroidal anti-inflammatory drugs (NSAIDs), muscle relaxants, anticancer chemotherapy drugs, biological modifiers, monoclonal antibodies (eg Omalizumab) and latex are common allergens in the hospital setting.  

Food-induced anaphylaxis associated with exercise usually affects teenagers. This is characterized by anaphylaxis occurring when exercise takes place within 2 to 4 hours of ingestion of a specific food. This may be food-independent or food-dependent; may be encountered after ingestion of celery, shellfish, and wheat.  

Idiopathic anaphylaxis occurs when the trigger of the anaphylaxis is unknown or cannot be identified despite thorough history, allergen skin tests, IgE levels, and provocation tests. Allergen immunotherapy and insect sting are also common causes of anaphylaxis.