- Allergic conjunctivitis/rhinitis are associated with considerable morbidity when undertreated.
- The diagnosis of allergic conjunctivitis/rhinitis is often missed or delayed.
- Complications of allergic conjunctivitis/rhinitis include exacerbation of asthma, sinusitis, middle ear infections and effusions, and sleep disturbances.
- There are multiple medical modalities for the treatment of allergic conjunctivitis/rhinitis.
Patients with symptoms related to common allergies are frequently treated in emergency departments. Often, the specific diagnosis of an allergic reaction is missed. This is especially true in the pediatric patient, in whom upper respiratory infections, which have clinical manifestations similar to allergic presentations, are extremely common. Recognizing and either initiating treatment or referring pediatric patients with allergic diseases for further follow-up is important because undertreatment of these illnesses can result in long-term morbidity. It is becoming increasingly well studied and appreciated that the symptoms of uncontrolled allergic symptoms have significant negative impact on the quality of patients' lives. Common allergic presentations in the emergency department include asthma, eczema, allergic conjunctivitis, and allergic rhinitis. Current literature emphasizes the interrelationship and overlap between these illnesses, especially allergic conjunctivitis and rhinitis: the two diseases are often discussed together as allergic rhinoconjunctivis.1–5 Asthma and eczema are discussed in detail in other chapters; this chapter will focus on allergic conjunctivitis and allergic rhinitis.
Allergic illnesses are most commonly seen in patients with a history of atopy, which is defined as a genetically determined hypersensitivity to environmental antigens.6 The most common form of hypersensitivity, type 1, is associated with IgE antibody and is the cause of most of the allergic presentations seen in the emergency department. Contact of IgE antibody with mast cells triggers mast cell degranulation, which results in the release of multiple inflammatory mediators; early-phase reactants include leukotriene C4 and prostaglandin D2. The late-phase response involves the recruitment of neutrophils, eosinophils, and macrophages. Histamine released on mast cell activation can cause pruritis, bronchospasm, increased vascular permeability, and vasodilation.6 Asthma, hay fever, allergic conjunctivitis, and allergic rhinitis can all be triggered by type 1 responses to environmental antigens. The most severe manifestation of a type 1 reaction is anaphylaxis, which can be fatal. Anaphylaxis is discussed in a separate chapter. Common indoor allergens include house dust mites, cockroaches, and pet allergens; these often cause persistent, perennial symptoms. Outdoor allergens include pollen from grass and trees—these tend to cause seasonal symptoms.1–5
The conjunctiva in a mucosa is similar to the nasal mucosa and possesses a relatively large surface area that reacts to the same allergens. The conjunctiva is connected to the nose via the lacrimal ducts; in this sense, it is part of the airway. The association of allergic conjunctivitis with allergic rhinitis is such that some authors group the two together under the heading “allergic rhinoconjunctivitis.” There are several specific classifications of allergic conjunctivitis.7
Seasonal allergic conjunctivitis (SAC) implies that patients have symptoms for ...