Allergic rhinitis (including seasonal and perennial rhinitis) is a common condition characterized by an inflammation of the nasal mucosa due to an allergic reaction in response to airborne allergens exposure.
Allergic rhinitis is one of the most widely spread allergic conditions. There are two types of allergic rhinitis distinguished. The first type is seasonal rhinitis (hay fever) occurs only in the seasons when there is a high concentration of pollens in the air (spring, summer, and early autumn). Another type is perennial allergic rhinitis is observed during the whole year in an intermittent or continuous manner without a seasonal incidence peak. Triggering allergens include pollens, dust mites, molds, and animal dander. Additionally, occupational rhinitis is diagnosed when certain occupational exposures are associated with rhinitis symptoms. It should be outlined that seasonal rhinitis is almost exclusively allergic, while perennial rhinitis may be of nonallergic etiology (up to ¼ of cases).
Allergic rhinitis develops as a type I hypersensitivity. Allergic reactions of this type are characterized by an abnormal production of specific IgE that is attached to mast cells and basophils. After exposure to specific allergens, these cells release histamine, leukotriene, and prostaglandins causing vasodilatation, increased permeability and as result edema of the mucous membranes.
- Family history of allergic diseases;
- Personal history of any allergic reactions, asthma, atopic dermatitis, food allergy, etc.;
- Smoking and exposure to air pollutants;
- Women are also more likely to develop allergic rhinitis;
Hay fever typically is caused by exposure to different seasonal plant allergens such as tree pollens (which are present in the air in spring), grass pollens (in summer) and weed pollens (present in summer and autumn). Sometimes mold spores also trigger seasonal allergic rhinitis.
Perennial rhinitis is related to chronic, all year round exposure to indoor allergens such as the house dust mites (Dermatophagoides farinae and Dermatophagoides pteronyssinus), pet dander and furs, cockroach derived proteins, mold spores, etc.
Allergic occupational rhinitis may be triggered by platinum salts, reactive dyes, acid anhydrides, any plant or animal-derived allergens, flour, latex, and many other chemical compounds and natural proteins.
Allergic rhinitis usually manifests with:
- Frequent sneezing;
- Episodes of a runny nose (rhinorrhea) with watery nasal discharge or nasal congestion;
- Itching of the nose, eyes, and skin;
- Impaired smell (anosmia) and sometimes impaired hearing;
- Sleep disturbances;
Sometimes allergic rhinitis is accompanied by conjunctivitis – inflammation of the thin mucous membrane that covers an eye characterized by excessive tearing, swollen eyelids, and red eyes.
In seasonal rhinitis, these symptoms usually develop during certain months when the allergens spread in the air. In perennial rhinitis symptoms are present throughout the year with occasional worsening. It happens due to changes in ambient temperature, exposures to smoke or air pollutants, irritating substances or small amounts of allergens. Perennial and seasonal rhinitis may coexist – the symptoms are present almost whole year and worsen during a pollen season.
- An elevated amount of eosinophils in complete blood count and increased serum IgE levels (which can be detected with a rapid test) are suggestive of allergic sensibilization;
- Skin prick testing is performed to verify the specific allergen and make a diagnosis;
- Measurement of specific IgE in the serum helps to reveal the allergens – this test is less sensitive than skin prick tests but is helpful to determine a specific allergen;
Prevention of flare-ups
Allergen avoidance is the best option to prevent disease exacerbations and lesser or eliminate the symptoms. The following measures are recommended to avoid all the possible allergens:
- Avoid allergenic foods;
- Clean the house frequently and exterminate cockroaches that may also trigger perennial rhinitis;
- Air conditioners and dehumidifiers along with HEPA filters are helpful for people prone to allergies;
- Fans can settle the dust in the air and, therefore, they should be avoided;
- Pets shouldn’t be kept at an apartment;
- Synthetic fiber pillows and impermeable mattress covers are considered hypoallergenic. It is recommended to remove all the carpets and minimize the clutter;
- Bedclothes should be washed in hot water (about 55°C/130°C);
- Mask over the nose and mouth with replaceable microfoam filters may be useful to limit exposure to inhaled allergens during a high season;
Oral antihistamines (fexofenadine, loratadine, desloratadine, cetirizine) are prescribed to minimize the symptoms, however, these drugs cannot cure the disorder. It is recommended to use antihistamines before exposure to a known trigger. In order to provide better symptoms control, these drugs should be taken during the whole pollen season.
Decongestants (vasoconstrictors) are available in the form of drops or spray and may be used from time to time during severe flare-ups. Antihistamines for intranasal administration such as azelastine and olopatadine are also effective in the treatment of rhinitis providing immediate relief.
Intranasal glucocorticosteroids (mometasone, beclomethasone) are highly effective, although their effects are not achieved immediately – they should be used for at least for 1 to 3 weeks before their effects become obvious. In severe cases, oral administration of glucocorticosteroids may be necessary.
When it is impossible to avoid the causative allergen-specific immunotherapy may be required. In general, it is more effective in seasonal allergic rhinitis than perennial rhinitis. Immunotherapy implies repeated exposure to an allergen which is administered subcutaneously or sublingually. It is considered that such kind of controlled exposure is helpful to desensitize the body and make it nonresponsive to the allergen.