ALLERGIC RHINITIS (NOSE)

Allergic Rhinitis (Nose)

Non-allergic Rhinitis
Some people, especially adults, suffer from persistently blocked sinuses and runny noses with episodes of sneezing. But when they have a skin test, the results are negative. Even though the inflammatory response within the nose looks the same as it does in allergic rhinitis, no offending allergen can be found. The reasons for this are not clear. Possibly the allergens have not yet been identified. Or there may be some other failure of the immune response that sets up a reaction that mimics the allergic response. Non-allergic rhinitis can be treated with avoidance of triggers if the trigger can be identified. Antihistamines and steroid nasal sprays may also be useful, as may be the antihistamine nasal spray azelastine (Astelin). (See Nasal Steroids.)
Some people have symptoms that are intermittent and provoked by irritants such as cold air, rapid temperature changes, smoke, and fragrances — a condition often called vasomotor rhinitis. These patients often test negative for an allergic response on a skin test. But in this case, because the irritant can often be identified, avoidance is a good first option. If the irritant cannot be identified or avoided, an anticholinergic drug such as nasal ipratropium (Atrovent) may help prevent these intermittent symptoms.


How Asthma Restricts Breathing

In a normal bronchus (A), muscles are relaxed so that air easily travels through the airway. Asthma causes two problems that can restrict breathing. First, the bronchial muscles contract (B), often in response to an allergen or some other asthma trigger. Second, the bronchial walls, which always have some degree of inflammation in people with asthma, become swollen and filled with excess mucus (C). Some of the cells involved in inflammation of the airways are mast cells and eosinophils, which release chemicals that cause the airways to narrow (D).

Allergic Asthma (Lungs)
Asthma is an inflammatory disease of the airways, and as such it affects how well — or not — a person can breathe. Asthma can be the result of an allergic reaction, but some people have asthma attacks that are triggered not by allergens but by irritants like smoke or even by exercise. Whatever the cause, anyone who has asthma or who lives with a family member who has asthma knows it can be a debilitating and potentially life-threatening disease.
Asthma is a major public health problem in the United States. And the disease has been on the increase for more than 20 years. The National Heart, Lung, and Blood Institute (NHLBI) estimates that asthma affects around 15 million Americans, of whom nearly 5 million are under age 18. Asthma attacks can be relatively mild or so severe they leave a person struggling for the very air needed to sustain life. When a healthy person inhales, oxygen-laden air passes easily into the lungs via the branching tubes known as bronchi and bronchioles. The destination of the inhaled air is the grapelike arrangement of small sacs called alveoli and their networks of blood vessels deep in the lung tissue. There, an exchange takes place: Oxygen passes into the bloodstream, and carbon dioxide, a waste product, enters the lungs. As you exhale, the carbon dioxide exits the same way the oxygen-laden air entered.

In asthma, the flow of air through the airways is restricted, and air cannot travel as easily as it should (see How Asthma Restricts Breathing ). Sometimes the problem is temporary; at other times it persists, and the airways are permanently damaged in a process called remodeling.

Allergic asthma is the result of what happens during an inflammatory response caused by an allergic reaction. In non-allergic asthma, which is more common in adults, some other, as yet poorly understood, mechanism accounts for the inflammation.

During an allergic reaction, inflammatory chemicals released by both mast cells and eosinophils cause inflammation in the airways. This causes the airway walls to thicken and the muscles in those walls to contract, narrowing the passage. Mucus then begins to fill the narrowed passage, and the airways become obstructed further. Should the muscles start to spasm, this exacerbates the situation. In a severe asthma attack, there’s more of everything — more inflammation, more muscle spasms, more mucus. The combination makes breathing very difficult and produces the distinctive wheezing whistle of asthmatic breathing.

Allergic Conjunctivitis (Eyes)
Allergies of the eye affect about 20% of Americans each year and are on the rise. The same inhaled airborne allergens — pollens, animal dander, dust mites, and mold — that trigger allergic rhinitis can lead to seasonal or year-round allergic conjunctivitis (inflammation of the conjunctiva, the lining of the eye). In this way, allergic conjunctivitis is a close cousin of allergic rhinitis, which makes sense because they are both IgE-mediated allergic responses. About 50% of allergic conjunctivitis sufferers, who tend to be young adults, have other allergic diseases or have a family history of allergies. The symptoms, which can be seasonal or year-round (about 80% of eye allergies are seasonal), are itchy and red eyes, tearing, edema (swelling) of the conjunctiva or eyelid, and a mucous discharge. Contact dermatitis (see Contact Dermatitis) can also affect the eyelid or the conjunctiva, but in that case the allergens are typically cosmetics, eye medications (such as topical neomycin), and preservatives (such as thimerosal). Although it can be uncomfortable, you can rest assured that uncomplicated allergic conjunctivitis is not a threat to vision.
A more serious condition, however, is atopic keratoconjunctivitis, which occurs in as many as 25% of atopic dermatitis sufferers and can result in loss of sight. Atopic keratoconjunctivitis may start in the teen years, but it most often appears between ages 30 and 50. People with atopic keratoconjunctivitis complain of itching, burning eyes, and blurred vision. Often they have a mucous discharge and are sensitive to sunlight. Vernal keratoconjunctivitis is another serious but rare eye disease that is sometimes related to allergies. The disorder appears mainly in young boys who can outgrow the condition when they reach puberty. The disorder is rare in the colder northern climes, preferring warmer, subtropical climates. If you think you have allergic conjunctivitis that isn’t responding to treatment, see your doctor or ophthalmologist.

Allergic Conjunctivitis (Eyes)
Diagnosing and Treating Allergic Conjunctivitis
Seasonal and year-round allergic conjunctivitis usually can be confirmed by your doctor based on your symptoms. Testing is not usually needed to diagnose the condition, but skin testing may help identify the allergens. If your symptoms don’t quickly respond to treatment, see your doctor in case you have a more serious eye condition.
Avoidance is the name of the game. If you are allergic to cats, avoid them. If you pet a cat, don’t touch your eyes, and be sure to wash your hands immediately afterward. Or if pollen is your nemesis, keep your windows closed and air conditioning going in pollen season. Also, don’t rub your eyes, because rubbing causes mast cells to release their histamine and other inflammatory chemicals, which worsens symptoms. Because allergic conjunctivitis can give you dry eyes, and taking the older first-generation oral antihistamines can aggravate that symptom, use artificial tears frequently for relief and because they can dilute allergens in the eye. Artificial tears are available without prescription.

As with other IgE-mediated allergic responses, allergic conjunctivitis can be treated with the newer generation of antihistamines, mast cell stabilizers, and corticosteroids. For symptoms that persist despite oral antihistamines, switch to regular use of a mast cell stabilizer (nedocromil) or an antihistamine eye drop. Eye drops also work faster than oral medications when you are having an acute attack. Several brands of eye drops, such as Opcon-A, Naphcon A, Vasocon-A, and Visine-A, are available over the counter. Your pharmacist will be able to advise you. Some of the newer antihistamines — olopatadine (Patanol), ketotifen (Zaditor)— may also act as mast cell stabilizers, have anti-inflammatory properties, or both. Because of the potential for harmful side effects, use topical corticosteroids only under the guidance of your ophthalmologist. Left to your own resources, you risk glaucoma, cataracts, or a devastating viral infection that can lead to blindness.