Asthma is a disease that is characterized by recurrent epi­sodes of difficult breathing and by wheezing, with periods of nearly complete freedom from symptoms. The episodes of difficulty are due to a narrowing of the bronchial tubes, swelling of the bronchial walls, and increased mucus production. Asthma symptoms may be sporadic and mild, they may occur frequently in spells of fluctuating severity, or they may become continuous and incapacitating. A variety of factors may induce an asthmatic attack in a susceptible person: Immunological These factors are allergens that can induce asthma attacks in allergic patients (see also Allergens). Nonimmunological Viral respiratory infections, aspirin and re­lated drugs, weather, air pollution, inhaled irritants, emotional responses, and exercise, among other factors, can influence or precipi­tate asthma attacks. Respiratory infections are among the most common causes of asthma attacks. Recent studies have shown that respiratory viruses are capable of causing asthma, but there is considerable doubt that bacterial infections play a significant role in the production of asthma. In the past, it was suggested that asthma symptoms are related to bacterial allergy, and patients were frequently treated with bacterial vaccines. Today, most authorities are of the opinion that bacterial allergy is not a frequent cause of asthma; therefore, immunotherapy using bacterial vaccines has, for the most part, been abandoned. Concerning the psychological factors involved, much has been writ­ten about the role of emotion in asthma and other allergies, but no convincing evidence exists that psychogenic factors actually cause allergies as such. On the other hand, there is little doubt that emo­tional factors can precipitate asthma attacks or aggravate allergies. Conversely, psychiatric disturbances may result from a chronic inca­pacitating condition such as asthma that is not treated properly. For these reasons, patients with severe allergies, like many patients with other chronic, incapacitating diseases, may require psychiatric counseling. See also Bacterial Allergy.

Systemic lupus erythematosus, abbreviated SLE, is an autoallergic disease. It frequently affects young women and may involve many different organs. In more serious cases, the kidneys and brain are often involved. Patients with SLE exhibit a variety of antibodies, which are directed against nuclear components of their cells. Detection of these antibodies (antinuclear antibodies) in the serum is helpful in diagnosis. The cause of SLE is unknown, but immunological factors acting on a suitable genetic background are believed important. There appears to be an important loss of immune regulatory function with decrease in suppressor T cell activity in SLE.

Eosinophils are certain types of blood cells often associated with asthma. Their presence in relatively large amounts in the blood, spu­tum, or nasal secretions is frequently seen in symptomatic allergic states. Pulmonary Function Tests Pulmonary function tests are helpful as indicators of the severity of the asthma, the degree of reversibility, and the likely response to certain treatments. Measuring Arterial Blood Gases Arterial blood gases are measured to evaluate the severity of the asthma. The blood is usually low in oxygen during a severe attack. At first, the patient may be breathing so fast that more carbon dioxide than usual is breathed out. A patient who becomes fatigued will retain carbon dioxide and thus risk respiratory failure.

Because tobacco smoke is noxious (that is, it consists of such gases as carbon monoxide and particulates), an asthma patient is apt to experience difficulty when exposed to it. Thus tobacco smoke should be avoided as much as possible. My seventeen-year-old-daughter is a chronic asthmatic and has been so since infancy. She is often absent from school because of her allergy, and the pressures of school build up, which greatly aggravates her condition. Is there anything I can do? A note from your physician to the principal (or, in rare cases, the school board) should help. Perhaps special arrangements can be made for tutoring at home. Since stress, as you suggest, aggravates your daughter’s condition, everything possible should be done to re­move pressures from her daily life. Our son, who is three-and-a-half, suffers from bronchial asthma. Would lowering the humidity in our house make it easier for him to breathe? Asthmatic patients generally do better in an atmosphere of constant humidity. A low-humidity environment is usually best. Even in the best-controlled patients, however, many things can precipitate an asthma attack, for example, cold air, noxious fumes, emotional stress, and infections.

See Arachidonic Acid.

No one is allergic to a substance the first time it is encountered; a period of sensitization precedes the onset of the allergy. Two years is a typical period, though some allergies appear sooner and some later.