Clinical immunology And Allergy: Rhinitis

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Rhinitis is an inflammation of the mucous membrane of the nose, caused by a virus infection e.g. the common cold or by an allergic reaction e.g. hay fever. It results in rhinorrhea, congestion, nasal itch, sneezing etc.  Allergic rhinitis or hay fever, occurs when the immune system overreacts to particles in the air that you inhaled. Non allergic rhinitis involves chronic sneezing or having a congested, drippy nose with no apparent cause. The symptoms of nonallergic rhinitis are similar to those of hay fever allergic rhinitis but there is no identified allergic reaction involved.

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.

The inflammation is caused by viruses, bacteria, irritants or allergens. The most common kind of rhinitis is allergic rhinitis, which is usually triggered by airborne allergens such as pollen and dander. Allergic rhinitis may cause additional symptoms, such as sneezing and nasal itching, coughing, headache, fatigue, malaise, and cognitive impairment. The allergens may also affect the eyes, causing watery, reddened, or itchy eyes and puffiness around the eyes. The inflammation results in the generation of large amounts of mucus, commonly producing a runny nose, as well as a stuffy nose and post-nasal drip. In the case of allergic rhinitis, the inflammation is caused by the degranulation of mast cells in the nose. When mast cells degranulate, they release histamine and other chemicals, starting an inflammatory process that can cause symptoms outside the nose, such as fatigue and malaise. In the case of infectious rhinitis, it may occasionally lead to pneumonia, either viral or bacterial. Sneezing also occurs in infectious rhinitis to expel bacteria and viruses from the respiratory tract.

Rhinitis is very common. Allergic rhinitis is more common in some countries than others; in the United States, about 10–30% of adults are affected annually. Mixed rhinitis (MR) refers to patients with nonallergic rhinitis and allergic rhinitis. MR is a specific rhinitis subtype. It may represent between 50 and 70% of all AR patients. However, true prevalence of MR has not been confirmed yet.

Types

Rhinitis is categorized into three types (although infectious rhinitis is typically regarded as a separate clinical entity due to its transient nature): (i) infectious rhinitis includes acute and chronic bacterial infections; (ii) nonallergic rhinitis  includes vasomotor, idiopathic, hormonal, atrophic, occupational, and gustatory rhinitis, as well as rhinitis medicamentosa (drug-induced); (iii) allergic rhinitis, triggered by pollen, mold, animal dander, dust, Balsam of Peru, and other inhaled allergens.

Infectious

Rhinitis is commonly caused by a viral or bacterial infection, including the common cold, which is caused by Rhinoviruses, Coronaviruses, and influenza viruses, others caused by adenoviruses, human parainfluenza viruses, human respiratory syncytial virus, enteroviruses other than rhinoviruses, metapneumovirus, and measles virus, or bacterial sinusitis, which is commonly caused by Streptococcus pneumoniae, Haemophilus influenzae, and Moraxella catarrhalis. Symptoms of the common cold include rhinorrhea, sneezing, sore throat (pharyngitis), cough, congestion, and slight headache.

Allergic

Allergic rhinitis or hay fever may follow when an allergen such as pollen, dust, or Balsam of Peru is inhaled by an individual with a sensitized immune system, triggering antibody production. These antibodies mostly bind to mast cells, which contain histamine. When the mast cells are stimulated by an allergen, histamine (and other chemicals) are released. This causes itching, swelling, and mucus production.

Symptoms vary in severity between individuals. Very sensitive individuals can experience hives or other rashes. Particulate matter in polluted air and chemicals such as chlorine and detergents, which can normally be tolerated, can greatly aggravate the condition.

Characteristic physical findings in individuals who have allergic rhinitis include conjunctival swelling and erythema, eyelid swelling, lower eyelid venous stasis, lateral crease on the nose, swollen nasal turbinates, and middle ear effusion.

Even if a person has negative skin-prick, intradermal and blood tests for allergies, they may still have allergic rhinitis, from a local allergy in the nose. This is called local allergic rhinitis. Many people who were previously diagnosed with nonallergic rhinitis may actually have local allergic rhinitis.

A patch test may be used to determine if a particular substance is causing the rhinitis.

Rhinitis medicamentosa

Rhinitis medicamentosa is a form of drug-induced nonallergic rhinitis which is associated with nasal congestion brought on by the use of certain oral medications (primarily sympathomimetic amine and 2-imidazoline derivatives) and topical decongestants (e.g., oxymetazoline, phenylephrine, xylometazoline, and naphazoline nasal sprays) that constrict the blood vessels in the lining of the nose.

Chronic atrophic rhinitis

Chronic rhinitis is a form of atrophy of the mucous membrane and glands of the nose.

Rhinitis sicca

Chronic form of dryness of the mucous membranes.

Polypous rhinitis

Chronic rhinitis associated with polyps in the nasal cavity.

Media contacts ,
Sana Jorge
Managing Editor
Journal of Clinicalimmunology And Allergy