Allergic rhinitis

1 - Mechanisms

This is an allergic reaction involving IgE and T helper type 2 lymphocytes. The contact of the nasal mucosa with the allergen causes the release of histamine, leukotrienes, prostaglandins.

2 - Description

Rhinitis manifests as a clear runny nose that can lead to nasal obstruction. It is associated with sneezing. The association with conjunctivitis (red eyes that cry and itchy) is common.
The evolution can be towards asthma or favor the appearance of otitis.
The symptoms can be troublesome enough to alter the quality of life to a level equivalent to that of asthma, upsetting social activities. They can also degrade school performance but the sedative effect of antihistamine drugs can also play.
An allergic cause of rhinitis must be theoretically demonstrated by a skin test (prick test) or by the search for specific immunoglobulin E in the blood. This is rarely necessary in case of seasonal allergy, more in case of perennial rhinitis.

3 - Causes

Allergy seems to be favored by various factors. Too clean, as described in the "hygienist hypothesis", could favor the appearance of allergic phenomena. In adults, alcoholism is a factor favoring rhinitis.
The allergens can be pollens (we talk about seasonal allergic rhinitis, hay fever or pollinosis), animal hair, mites, dust.

4 - Statistics

Allergy is responsible for two-thirds of the child's rhinitis and one-third of that of the adult.
More than 35% of adults suffer from allergic rhinitis.
Prevalence in childhood is increasing, although it is not found anywhere in the world.
Four-fifths of allergic rhinitis begins before the age of 20, and the incidence appears to be highest in early adolescence5. It reaches boys a little more frequently, but the ratio by sex is equalized in adulthood. It tends to decrease with age.
Allergic rhinitis is common in asthmatics and it is possible that the first favors the second disease, or at least a risk factor.

5 - Seasonal allergic rhinitis

Seasonal allergic rhinitis is also called pollenosis, "rhinoconjunctivitis allergic to pollens", or more commonly "hay fever". It is opposed to "perennial" rhinitis, which is caused by a non-seasonal allergenic substance (mites, for example).
Its main manifestations are sneezing, rhinorrhea, nasal obstruction, itchy nose and eyes, watery eyes. These symptoms occur as a result of exposure to allergenic pollens, whose presence in the air is variable depending on the season. In Western Europe, for example, they are species such as hazel and alder in late winter, followed by birch, then oak in spring, grasses in early summer, ragweed and plantain in late summer. The weather conditions also influence: the concentration of pollen in the air is higher in hot and dry weather.
Seasonal allergic rhinitis usually starts in childhood. It is rare after 65 years. Asthma is often associated with it (in about 20% of cases). Allergic rhinitis may also be associated with allergic conjunctivitis or other conditions such as sinusitis or otitis.
Complementary examinations are rarely necessary to make the diagnosis. Skin tests are only useful if desensitization is considered. There is also a long-term allergic rhinitis, which can spread over several years, it is in these cases that the desensitization is ideal.

6 - Treatments

The treatments are mainly symptomatic: possible eviction of the allergen (even if the evidences of the effectiveness of this eviction are lacking in the case of the mites), sodium cromoglicate in nasal solution (in eye drops in case of ocular symptoms), corticosteroids local, antihistamine oral or nasal. Nasal irrigation with a simple saline solution can be effective. Nasal corticosteroids appear to be more effective than oral antihistamines, the former not acting on conjunctivitis. Leukotriene antagonists are comparable in efficacy to antihistamines. Corticosteroids intramuscularly are not devoid of side effects, sometimes serious.

Desensitization involves continuously administering an allergen for several months or years, more and more. Administered subcutaneously, desensitization has proved effective, but sometimes at the cost of adverse effects (local reactions at the injection sites, urticaria), sometimes severe (bronchospasm, angioedema, asthma, anaphylactic reaction), requiring monitoring approximately one hour after each injection. It also has some effectiveness in preventing progression to asthma. Sublingual administration (lyophilisates) is an effective technique in pollen allergy but seems more controversial in other types of allergy.
Timothy grass pollen (Grazax) is a treatment that can be used orally and is not reimbursed by social security. A four-month treatment is necessary for a gain of four days of comfort. In addition, there are no comparative tests with subcutaneous desensitization. Two-thirds of the patients experienced side effects as a result of this treatment.
Acupuncture seems to have limited effectiveness.
Even if it is not a drug in France or a treatment, quercetin (quercetol) flavonoid extracted from plants such as capers, ..., sorrel, blueberries, ... seems to strongly reduce inflammatory symptoms, connective, nasal discharge and wheezing It is sometimes associated with turmeric.
Elderberry seems effective in regulating and eliminating mucus or runny nose even in very crowded noses