Conjunctivitis, also known as pink eye, is inflammation of the outermost layer of the white part of the eye and the inner surface of the eyelid. It makes the eye appear pink or reddish. Pain, burning, scratchiness, or itchiness may occur. The affected eye may have increased tears or be "stuck shut" in the morning. Swelling of the white part of the eye may also occur. Itching is more common in cases due to allergies. Conjunctivitis can affect one or both eyes.
Allergies, also known as allergic diseases, refer to a number of conditions caused by the hypersensitivity of the immune system to typically harmless substances in the environment. These diseases include hay fever, food allergies, atopic dermatitis, allergic asthma, and anaphylaxis. Symptoms may include red eyes, an itchy rash, sneezing, coughing, a runny nose, shortness of breath, or swelling. Note that food intolerances and food poisoning are separate conditions.
An allergen is a type of antigen that produces an abnormally vigorous immune response in which the immune system fights off a perceived threat that would otherwise be harmless to the body. Such reactions are called allergies.
Allergic rhinitis, of which the seasonal type is called hay fever, is a type of inflammation in the nose that occurs when the immune system overreacts to allergens in the air. Signs and symptoms include a runny or stuffy nose, sneezing, red, itchy, and watery eyes, and swelling around the eyes. The fluid from the nose is usually clear. Symptom onset is often within minutes following allergen exposure, and can affect sleep and the ability to work or study. Some people may develop symptoms only during specific times of the year, often as a result of pollen exposure. Many people with allergic rhinitis also have asthma, allergic conjunctivitis, or atopic dermatitis.
Rhinitis, also known as coryza, is irritation and inflammation of the mucous membrane inside the nose. Common symptoms are a stuffy nose, runny nose, sneezing, and post-nasal drip.
Prednisolone is a corticosteroid, a steroid hormone used to treat certain types of allergies, inflammatory conditions, autoimmune disorders, and cancers. Some of these conditions include adrenocortical insufficiency, high blood calcium, rheumatoid arthritis, dermatitis, eye inflammation, asthma, and multiple sclerosis. It can be taken by mouth, injected into a vein, used topically as a skin cream, or as eye drops. It has been used to treat sudden sensorineural hearing loss (SSNHL); SSNHL has sometimes occurred after a covid infection, and has been treated with prednisolone.
Tetryzoline is a drug used in some over-the-counter eye drops and nasal sprays. Tetryzoline was patented in 1954, and came into medical use in 1959.
Omalizumab, sold under the brand name Xolair, is a medication used to treat asthma, nasal polyps, and urticaria (hives).
Cromoglicic acid (INN)—also referred to as cromolyn (USAN), cromoglycate, or cromoglicate—is traditionally described as a mast cell stabilizer, and is commonly marketed as the sodium salt sodium cromoglicate or cromolyn sodium. This drug prevents the release of inflammatory chemicals such as histamine from mast cells.
Allergic conjunctivitis (AC) is inflammation of the conjunctiva due to allergy. Although allergens differ among patients, the most common cause is hay fever. Symptoms consist of redness, edema (swelling) of the conjunctiva, itching, and increased lacrimation. If this is combined with rhinitis, the condition is termed allergic rhinoconjunctivitis (ARC).
Allergen immunotherapy, also known as desensitization or hypo-sensitization, is a medical treatment for environmental allergies, such as insect bites, and asthma. Immunotherapy involves exposing people to larger and larger amounts of allergen in an attempt to change the immune system's response.
Olopatadine, sold under the brand name Opatanol among others, is a medication used to decrease the symptoms of allergic conjunctivitis and allergic rhinitis. It is used as eye drops or as a nasal spray. The eye drops generally result in an improvement within half an hour.
Ketotifen, sold under the brand name Zaditor among others, is a second-generation noncompetitive H1-antihistamine and mast cell stabilizer. It is most commonly sold as a salt with fumaric acid, ketotifen fumarate, and is available in two forms. In its ophthalmic form, it is used to treat allergic conjunctivitis. In its oral form, it is used to prevent asthma attacks or anaphylaxis, as well as various mast cell, allergic-type disorders.
Levocabastine (trade name Livostin or Livocab, depending on the region) is a selective second-generation H1 receptor antagonist which was discovered at Janssen Pharmaceutica in 1979. It is used for allergic conjunctivitis.
Nedocromil sodium is a medication considered as mast cell stabilizer which acts to prevent wheezing, shortness of breath, and other breathing problems caused by asthma. It is administered by an inhaler under the brand name Tilade, and as an eye drop under the brand name Alocril. The effects of nedocromil versus asthma are gradual rather than fast-acting and it is not indicated for acute respiratory distress compared to fast acting bronchodilators like albuterol or other well-known inhaler medications. Liquid preparations of nedocromil are available in the UK under the name Rapitil for use for allergic eye reactions. Nedocromil sodium has been shown to be effective in alleviating symptoms of allergic conjunctivitis.
Azelastine, sold under the brand name Optivar among others, is a H1 receptor-blocking medication primarily used as a nasal spray to treat allergic rhinitis (hay fever) and as eye drops for allergic conjunctivitis. Other uses may include asthma and skin rashes for which it is taken by mouth. Onset of effects is within minutes when used in the eyes and within an hour when used in the nose. Effects last for up to 12 hours.
Egg allergy is an immune hypersensitivity to proteins found in chicken eggs, and possibly goose, duck, or turkey eggs. Symptoms can be either rapid or gradual in onset. The latter can take hours to days to appear. The former may include anaphylaxis, a potentially life-threatening condition which requires treatment with epinephrine. Other presentations may include atopic dermatitis or inflammation of the esophagus.
Loteprednol is a topical corticosteroid used to treat inflammations of the eye. It is marketed by Bausch and Lomb as Lotemax and Loterex.
Allergic inflammation is an important pathophysiological feature of several disabilities or medical conditions including allergic asthma, atopic dermatitis, allergic rhinitis and several ocular allergic diseases. Allergic reactions may generally be divided into two components; the early phase reaction, and the late phase reaction. While the contribution to the development of symptoms from each of the phases varies greatly between diseases, both are usually present and provide us a framework for understanding allergic disease.
Mast cell stabilizers are medications used to prevent or control certain allergic disorders. They block mast cell degranulation, stabilizing the cell and thereby preventing the release of histamine and related mediators. One suspected pharmacodynamic mechanism is the blocking of IgE-regulated calcium channels. Without intracellular calcium, the histamine vesicles cannot fuse to the cell membrane and degranulate.
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