Allergies [30] Allergy is a disorder of the immune system often also referred to as atopy.
Antidepressants [27] An antidepressant is a psychiatric medication used to alleviate mood disorders, such as major depression and dysthymia.
Arthritis [11] Arthritis is a group of conditions involving damage to the joints of the body.
Cancer [16] Cancer is a class of diseases in which a group of cells display uncontrolled growth
Cardio & Blood [1] Risk factors for heart disease: infections
Cholesterol [2] A fat-like substance called a lipid. It is used to build cell membranes, hormones and bile acids
Diabetes [21] The inability of the body to produce, or the inability to metabolize, the human hormone insulin; Diabetes insipidus, usually a disorder of the ...
Epilepsy [4] Epilepsy is a common chronic neurological disorder characterized by recurrent unprovoked seizures
Gastrointestinal [1] The digestive tract is the system of organs within multicellular animals that takes in food...
General Health [180] The infant, child or young person?s current health condition
Herbal [15] Herbal tea, herbal medicine
Hormonal [18] Hormones - Proteins produced by organs of the body that trigger activity in other locations.
Men's Health [1] For men on fitness, health, sex, caree
Pain relief [17] Pain management is the medical discipline concerned with the relief of pain.
Skin care [24] The skin is the outer covering of the body
Weight Loss [23] Loss of body weight by dieting or due to various easting disorders or medical conditions.
Women's Health [35] Find information on women's health issues, and lifestyle at the Women's Health
Awaiting moderation 3717 Article
|
Late-phase allergic reactions LATE-PHASE ALLERGIC REACTIONS
If an allergic patient is given a skin-prick test there will be a strong response -known as a wheal-and-flare reaction - almost immediately. This redness and itching subsides after some time, but then a different sort of reaction can set in, producing a larger, less itchy, but more painful lump. This is known as the late-phase reaction, and it is produced by the messenger substances called prostaglandins (see p28).
When a person encounters allergens in everyday life, late-phase reactions are more difficult to discern, especially if there is frequent exposure to the allergen. But such a
reaction can sometimes be observed in asthmatic patients, for example. Brief exposure to their allergen will produce an acute reaction almost immediately, followed by recovery, followed by a more insidious return of the asthma between four and 12 hours after the exposure. The late-phase reaction has usually exhausted itself by the next day.
Late-phase reactions are important, because they probably contribute substantially to the development of 'chronic' allergic reactions a long-term condition in which the patient is scarcely ever free of symptoms, although the severity of the symptoms may fluctuate. During late-phase reactions, the affected organ (eg the bronchi or the skin) tends to be more sensitive to non-specific irritants, so the symptoms may be sparked off again very easily, even if the allergen has been removed. A succession of late-phase reactions can easily lead to a situation where the organ is constantly over-reacting to minor irritants.
Certain drugs block late-phase reactions by preventing cell membranes from releasing the phospholipid molecules that would normally be used to make prostaglandins. The drugs that do this are
corticosteroids {eg prednisolone) which mimic the action of hormones produced by the body. The fact that corticosteroids are so useful in controlling asthmatic symptoms shows what an important role late-phase reactions can have in allergic illness.
Corticosteroids are not simply used for allergy treatment - they suppress inflammation generally because prostaglandins are widespread messengers, produced in a variety of ways. They therefore find a use in diseases such as rheumatoid arthritis where inflammation needs to be controlled.
*52\180\8*
Allergies
«Online Pharmacy. Cheap Prescription Drugs.»
Print Viewed: 252
| Keywords for this page: Late-phase allergic reactions |
|
|