Air and Breathing
Nose Inflammation --Rhinitis
The ear, nose, and throat are the most common target organs for air and food allergens. Congestion or inflammation of the nose (rhinitis), sinuses (sinusitis), and throat (pharyngitis) may be due to infection, airborne irritants and allergens; food allergy may be the undiagnosed cause of these common problems.
Rhinitis means inflammation in the nose. Rhinitis may be intermittent or persistent. The cause of intermittent rhinitis is sometimes obvious; symptoms only occur at a specific time and place. Allergic rhinitis is one of the most obvious environmental diseases. Hay fever is the prototype of Type I allergy. The mechanism was thought to be a straight forward histamine-mediated response to inhaled antigen. Drugs that block histamine are effective in relieving hay fever symptoms. The early, immediate response is sneezing and anterior nasal discharge, often profuse.
The cause of persistent rhinitis is often concealed and some patients with this problem are treated with drugs and never discover the cause. Allergic responses in the nose are more easily studied than in the lung. There is reason to believe that there are similarities. Allergic rhinitis and asthma go together in attack patterns when the allergen is airborne. Food allergy is suggested by these respiratory symptoms: nasal stuffiness, snoring, increased mucus flow in nose and throat and recurrent sore throats. Recurrent middle ear "infections" are very common in the first five years of life and may be eliminated by proper diet revision. Milk, wheat, and egg white allergy are the most common cause of respiratory symptoms, but other foods can do this.
Infection: The nose, middle ear and sinuses are colonized by bacteria, fungi and sometimes host resident viruses. Some microprobe populations are well behaved and cause no symptoms. Other microbe populations are latent pathogens that expand and infect when conditions shift in their favor. These microbes also travel into the throat and into the lower airway; they may infect the bronchi (bronchitis) and lung (pneumonia). Even non-aggressive microbes living on the surface of the nasal cavity may induce immune-mediated hypersensitivity responses ( delayed pattern allergy).
Hay Fever and Allergy Ads
Hay fever is the most clear-cut case of allergy. Ads for antihistamines proclaim the simplest mechanism of allergy:
A similar reaction in the throat produces soreness, mucus flow, swelling, and difficulty in swallowing and breathing (pharyngitis, laryngitis). A similar reaction in the lungs produces cough, mucus obstruction to airflow, and asthmatic wheezing (bronchitis, asthmatic bronchitis).
The clinical practice of "Allergy" as a specialty has tended to restrict the definition of allergy to one pattern of immune reactivity described as "Atopy" by Coca and Cooke in 1925. The term "atopy" simply meant "strange disease". Allergists noticed connections among the "'strange diseases" including hay fever (seasonal allergic rhinitis and conjunctivitis), asthma and eczema - the three members of the atopic group. Study of atopic hypersensitivity revealed a common immune mechanism which further confirmed the allegiance of many allergists to atopy, with the exclusion of other allergic diseases from their field of interest. It was found that a single antibody species, IgE or "reaginic antibody", was responsible for some of the typical manifestations of atopy. An inherited tendency to make excessive amounts of IgE antibody is one characteristic of atopic individuals.
Nose Reactions and Skin Tests A convenient correlation between nose-reactive IgE and skin-reactive IgE was discovered. By introducing tiny amounts of suspected antigens into the skin, a local wheal and flare reaction, like a mosquito bite, is produced if reactive IgE is present on skin mast cells. The association of hay fever, asthma, and skin tests with allergy practice was further confirmed by the relative success of "allergy shots". These shots came to characterize the allergist's office; other aspects of allergy practice often were neglected.
Allergy shots are immunological treatments. The immune response to any reactive substance can be modified by giving repeated challenges of the reactive substances. Allergy shots for hay fever start with a serum containing the pollen antigens which caused positive skin responses. The antigens are administered in increasing concentrations by regular injections under the skin. It remains unclear how the shots work. One response to the injected antigen is the production of a second antibody population of the IgG class. These IgG antibodies are thought to compete with IgE antibodies, "blocking" the allergic response. It is also possible that the antigen injections stimulate suppressor T-cells or inhibit helper T-cells and reduce production of IgE.
Allergy shots have limited therapeutic application. The hay fever sufferer and some asthmatics with specific inhalant reactions to grass pollens do well with desensitization. Immunotherapy also protects patients who have had anaphylactic reactions to bee and wasp stings. Patients with complex reactivity, food reactions, and drug reactions do not do well with allergy shots, and the shots are not recommended.
Drugs Oral antihistamines and intranasal steroid sprays are the two best options. An inhaled steroid, Flonase, has been approved in the US for over the counter sales.
Food Allergy & Chronic Rhinitis
Food allergy causes chronic rhinitis with middle ear involvement in children. In infants and young children, nose congestion may present as mouth-breathing, sniffing, snuffling, snorting or snoring, and nose rubbing (sometimes known as the "allergic salute" - pushing the nose up with the palm of the hand until a crease develops across the skin of the nose). Increased mucus flow in nose and throat, ear-plugging with muffled hearing and ringing in the ears, recurrent middle ear "infection", recurrent sore throat, swelling of the neck lymph nodes (glands), chronic or recurrent cough, episodes of chest pain, "tightness", and/or wheezing with shortness of breath.
Food antigens arrive in the respiratory track by surface contact and via the circulation. Food proteins are processed by macrophages in the responding tissue. Antigen presenting cells continue to activate helper T-lymphocytes that continue to secrete lymphokines which may stimulate in turn the proliferation of IgE producing plasma cells and promote local infiltration of mast cells and eosinophils. In the nose and lung, eosinophils tend to accumulate and secrete major basic protein and free radicals that are toxic to the epithelium. This activity can prime the IgE-mediated, mast-cell response and the tissue activity combines immediate and delayed immune responses. Similar tissue events occur in the lungs. While antihistamines may be successful in blocking discrete acute phase responses, only steroids will inhibit the delayed reactions that cause chronic rhinitis and asthma.
Food allergy causes thick mucus secretion in the throat; many patients are bothered by the need to frequently clear their throats - this leads to unpleasant sounds, interrupted speech, and can seriously hamper the careers of singers, actors and people who must speak fluently and clearly in their work assignments. The extra mucus can hamper breathing at night and is associated with snoring. Patients often say they have recurring colds or sinus infections and often take antibiotics with the hope of stopping the symptoms. Chronic or recurrent cough, episodes of chest pain, "tightness", and wheezing with shortness of breath are symptoms of lower respiratory tract involvement. Sore throats can be caused by food allergy and may be acute- coming on with contact with a food or chronic- soreness which persists for weeks of months. Swelling of the neck lymph nodes ("glands") may be associated.
Pelikan reviewed the role of food allergy and noted that skin tests and IgE RAST tests had a low correlation with oral provocation of symptoms, suggesting that food allergy produced rhinitis via a non-IgE mechanism. Rhinitis responses to foods occur in a triphasic pattern - immediate within 20 minutes; late, 4-6 hours, and delayed 24-48 hours. Rhinitis was often associated with other symptoms, typical of systemic food allergy; general malaise, headache, middle-ear fluid, sinus pressure and urticaria were common. The patients with delayed onset rhinitis had more headaches and general malaise than the immediate reacting group.