Allergy Library

The term rhinitis means inflammation of the nasal lining. It has certain characteristic features including recurrent sneezing, runny nose (rhinorrhoea), and itchy and blocked nose. Allergic rhinitis is extremely common and a global health problem. In children, boys are more likely to be affected than girls, and symptoms typically develop before 20 years of age. Children who exhibit persistent symptoms tend to grow into adulthood with the disorder, while up to 20% of children with seasonal symptoms will have resolution of the disorder by early adulthood. Allergic rhinitis may be seasonal, perennial, episodic or occupational. Some patients will experience perennial symptoms with seasonal exacerbations.

Important risk factors for developing allergic rhinitis:

Seasonal allergic rhinitis (Hay Fever)

Hay fever is medically known as seasonal allergic rhinitis. The condition is caused mainly by grass pollen in the UK and Ireland during spring and/or summer seasons. In other countries, other pollens such as; ragweed in the USA, birch tree pollen in Scandinavia, and cedar pollen in Japan, are the major cause of hay fever in these countries.

Hay fever varies in severity from mild forms, which are insignificant to a severity, which is crippling during the season, and sufferers may be unable to work or drive. The currently available treatment helps relief the symptoms so much that life during the hay fever season becomes normal again. Hay fever symptoms can affects the nose, the eyes and sometimes the chest: 

Perennial allergic rhinitis

When the allergic symptoms occur all year-round, the rhinitis is termed perennial allergic rhinitis. Triggers include allergens from animals, molds, and house dust mite. House dust mite and molds especially prefer warm, damp environment. Mites are typically found in beddings, carpets, curtains and soft toys. Molds are often present in house plants and can be isolated in piles of undisturbed papers such as old newspapers. Household pets are important causes of perennial allergic rhinitis with the major allergens found in their skin or dander and saliva. Cat allergens remain airborne for up to six hours and can be detected in household dust for several months after the animal has left.

Occupational rhinitis

Occupations associated with on the-the-job allergen exposure and may cause occupational rhinitis include Vets and laboratory workers handling animals, bakers allergic to flour, health care workers allergic to latex, etc. It is important to note that occupational rhinitis often precedes the development of Occupational asthma.

Episodic rhinitis

Episodic rhinitis occurs with intermittent exposure to allergens that do not follow seasonal or work-related trends. Episodic rhinitis is mostly related to intermittent exposure to animals or dusty environment.

Other forms of rhinitis

Infective:

Infective rhinitis may be acute or chronic. Chronic symptoms may be due to specific infection, such as fungi or tuberculosis. Chronic infection may also be the result of specific deficiencies of the immune system.

Non-allergic, non-infective rhinitis:

Allergic rhinitis: Disease mechanisms

Allergic rhinitis is an inflammatory response mediated by IgE antibodies. Patients with allergic rhinitis have allergen(s) specific IgE bound to receptors on the surface of mast cells. Within minutes of allergen(s) contact, cross-linking of adjacent IgE molecules occur leading to mast cell deregulation (emptying of granules). Mast cell granules contain a variety of chemical mediators such as histamine, leukotrienes and prostaglandins. Histamine causes the main features of allergic rhinitis including sneezing, nasal itching, and runny nose. Nasal congestion is more due to leukotrienes than to histamine. Hence antihistamines are not very effective at relieving nasal congestion.

Allergic rhinitis: Diagnosis

History

Detailed and careful history is essential in the investigation of all allergic diseases including allergic rhinitis. Key points to be reviewed when obtaining a rhinitis history include the following:

Some patients who are allergic to their pets will often deny obvious symptoms related to contact with their own pets. This is due to some sort of tolerance developed due to continuous allergen exposure. However, if they were to travel away for a few weeks, they might notice immediate reappearance of the allergic symptoms upon their return.

Nasal examination

No specific features are found exclusively in allergic rhinitis. Pale, bluish and swollen mucosa may be detected. Perhaps the most important role of examination is to look for structural causes of obstruction such as septal deviation or polyps. Other regions, which should be assessed, are the eyes (conjunctivitis), the ears (middle ear inflammation) and the skin (eczema).

Investigations

• Skin tests

• Blood tests

• Other tests are determined by the allergy specialist

Allergic rhinitis: Treatment

The most important element in the treatment of allergic rhinitis is information to the patients and, if the patient is a child, the parent should be the target for information. Successful treatment depends on the patients understanding of the nature of their disease. Broadly speaking there are three main options in the treatment of allergic rhinitis:

Allergen avoidance:

Allergen avoidance is an important measure in treating allergic rhinitis and should be encouraged. This approach is usually successful and should strictly be enforced when there is evidence of specific allergy to foods, drugs or animals. However, seasonal allergens such as grass and tree pollens have a widespread distribution, total eradication of these allergens is difficult if not impossible. It is also important to eliminate other local irritants as much as possible. The importance of a nonsmoking environment cannot be overstressed. Measures of allergen avoidance will differ depending on the nature of the allergen:

Drug treatment

Patients need medications for allergic rhinitis if avoiding the allergen is impossible or fails to control the symptoms. However, most patients will require drug treatment to obtain a substantial relief of symptoms. Patients with severe disease may require a combination of drugs to control their symptoms. Drug treatment for allergic rhinitis relies on two main classes of medications: antihistamines and corticosteroids nasal sprays.

Antihistamines will prevent and control nasal itch, sneezing, rhinorrhoea and allergic conjunctivitis. They are more effective in preventing the actions of histamine than they are at reversing the actions once established.

Intranasal corticosteroids exert anti-inflammatory effects that relieve symptoms of allergic rhinitis. These agents are considered the most effective drug treatment available for nasal allergic rhinitis symptoms.

Topical sodium cromoglycate represents an alternative anti-inflammatory agent to corticosteroids, particularly in young children.

Corticosteroids and sodium cromoglycate affect the underlying allergic process and should be used as first line treatment for most patients. Compliance may be a problem with cromoglycates, as they need to be used 3-6 times per day.

Topical anticholinergic drugs (e.g. Atrovent) and decongestants may have a part to play in defined circumstances. Topical decongestants should not be used for more than 5 days because of rebound congestion.

Antileukotriens antagonists, originally developed for the treatment of asthma, these agents have been found helpful in controlling symptoms of allergic rhinitis.

Monoclonal anti-IgE antibody (e.g. Omalizumab) forms complexes with free IgE blocking its interaction with mast cells and basophiles. Further studies are required before use can be recommended in allergic rhinitis.

Immunotherapy:

The majority of patients with seasonal and perennial allergic rhinitis may, in general, be effectively managed with a combination of allergen avoidance measures, intranasal corticosteroids and oral antihistamines. There remains a small group of subjects who, despite regular use of medication, continue to have marked symptoms or unacceptable side effects from their medication. These patients should be offered immunotherapy.