Allergies Health Article

Immunotherapy

Immunotherapy, also known as desensitization or allergy shots, alters the balance of antibody types in the body, thereby reducing the ability of IgE to cause allergic reactions. Immunotherapy is preceded by allergy testing to determine the precise allergens responsible. Injections involve very small but gradually increasing amounts of allergen, over several weeks or months, with periodic boosters. Full benefits may take as long as several years to achieve, and are not seen at all in about one in five patients. Patients are monitored closely following each shot because of the small risk of anaphylaxis.

Bronchodilators

Because allergic reactions involving the lungs cause the airways or bronchial tubes to narrow (as in asthma), bronchodilators, which cause the smooth muscle lining the airways to dilate, can be very effective. Some bronchodilators used to treat acute asthma attacks include adrenaline, albuterol, or other adrenergic stimulants, most often administered as aerosols. Theophylline, naturally present in coffee and tea, is another drug that produces bronchodilation. It is usually taken orally, but in a severe asthma attack is may be administered intravenously. Other drugs, including steroids, are used to prevent asthma attacks and in the long-term management of asthma.

Treatment of contact dermatitis

Calamine lotion applied to affected skin can reduce irritation. Topical corticosteroid creams are more effective, though overuse may lead to dry and scaly skin.

Treatment of anaphylaxis

The emergency condition of anaphylaxis is treated with injection of adrenaline, also known as epinephrine. Patients prone to anaphylaxis in response to food or insect allergies often carry an "Epi-pen" containing adrenaline in a hypodermic needle. Prompt injection may prevent a more serious reaction from developing.

Prognosis

Allergies may improve over time, although they often worsen. While anaphylaxis and severe asthma are life threatening, other allergic reactions are not. Learning to recognize and avoid allergy-provoking situations allows most patients with allergies to lead normal lives.

Health care team roles

Diagnosis and effective management of allergy symptoms involves cooperation and collaboration between the patient and an interdisciplinary team of health care professionals. The patient's primary care physician or pediatrician, allergy and immunology specialists, laboratory technologists, respiratory therapists, pharmacists, pharmacy assistants, and health educators are involved in helping patients and families gain an understanding of how to prevent effectively manage symptoms.

Patient education

Nurses, respiratory therapists, and health educators help patients learn how to prevent and manage allergy symptoms. They teach patients how to distinguish mild allergy symptoms from those requiring immediate medical attention. Pharmacists and pharmacy assistants may offer additional instruction about medication use and reiterate the importance of adhering to prescribed treatment.

Prevention

Avoiding allergens is the best means of limiting allergic reactions. For food allergies, there is no effective treatment except avoidance. By determining the allergens that cause reactions, most patients can learn to avoid allergic reactions from food, drugs, and contact allergens such as poison ivy or latex. Airborne allergens are more difficult to avoid, although keeping dust and animal dander from collecting in the house may limit exposure. Cromolyn sodium can prevent mast cell degranulation, thereby limiting the allergic response.

KEY TERMS

Allergen—A substance that provokes an allergic response.

Allergic rhinitis—Inflammation of the mucous membranes of the nose and eyes in response to an allergen; also known as hay fever.

Anaphylaxis—Increased sensitivity caused by previous exposure to an allergen that can result in blood vessel dilation and smooth muscle contraction. Anaphylaxis can result in sharp blood pressure drops and difficulty breathing.

Angioedema—Severe non-inflammatory swelling of the skin, organs, and brain that can also be accompanied by fever and muscle pain.

Antibody—A specific protein produced by the immune system in response to a specific foreign protein or particle called an antigen.

Antigen—A foreign protein to which the body reacts by making antibodies.

Asthma—A lung condition where the airways become constricted due to smooth muscle contraction, causing wheezing, coughing, and shortness of breath.

Atopic dermatitis—Inflammation of the skin as a result of exposure to airborne or food allergens; also known as eczema.

Conjunctivitis—Inflammation of the thin lining of the eye called the conjunctiva.

Contact dermatitis—Inflammation of the skin as a result of contact with a substance.

Delayed hypersensitivity reactions—Allergic reactions mediated by T cells that occur hours to days after exposure.

Granules—Small packets of reactive chemicals stored within cells.

Histamine—A chemical released by mast cells that activates pain receptors and causes cells to become leaky.

Immune hypersensitivity reaction—Allergic reactions that are mediated by mast cells and occur within minutes of allergen contact.

Mast cells—A type of immune system cell found in the lining of the nasal passages and eyelids, with an antibody called immunoglobulin type E (IgE) on its cell surface; mast cells release histamine from intracellular granules.