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In this Article

• Who are the "players" in the allergic cascade?
• What about a more detailed look at the "players?"
• What are cytokines?
• What is the "early phase" of an allergic reaction?
• What is the "late phase" of an allergic reaction?
• What are the consequences of the allergic cascade?
• How does understanding the allergic cascade help?
• Allergic Cascade At A Glance
• Allergic Cascade Glossary
• Allergic Cascade Index

How does understanding the allergic cascade help?

How can we put this new understanding of allergic reaction to good use? By looking closely at the complex steps involved in this chain of events, scientists have been able to find new and innovative treatments for common and troublesome allergic illnesses.

The most basic, and best, approach to caring for allergies is avoidance of the substances causing them, the allergens. Some allergens such as pet dander, foods, and medications are relatively easy to avoid. However, many other allergens, such as dust mites, molds, and pollens are more difficult to evade. Measures to reduce exposure to them, however, are still essential for the optimal treatment of allergies.

The most convenient approach to the treatment of allergies involves taking various medications. A classic example of an allergic medication is the standard antihistamine. The importance of histamine in allergic disease is illustrated by the effectiveness of antihistamines (medically termed H1 receptor blockers) in preventing certain allergic symptoms. They are effective in curtailing itching, sneezing, and runny nose. However, the more severe allergic reactions and symptoms of asthma require different treatments. Anti-inflammatory medications, such as steroids and leukotriene antagonists, may be required. Medications that widen the airways through the lungs (bronchial dilators) have also been a mainstay in the treatment of asthma and are particularly useful in controlling the immediate or early phase reaction. Current research is aimed at finding medications that are targeted at specific steps in the allergic cascade.

The last approach to the management of allergies attempts to interfere with the allergic antibody immune response. Allergy shots (immunotherapy) involve desensitizing a patient by injecting increasing amounts of the allergens to which the person is allergic. Over time, the immune system becomes less reactive to these allergens, generates less IgE in response to them, and becomes more tolerant upon re-exposure to them.

The Allergic Cascade At A Glance

• The allergic response is usually very selective for specific allergens.
• T- and B-lymphocytes play important roles in the allergic reaction.
• Mast cells and basophils release a variety of chemical mediators and cytokines that cause allergic inflammation.
• The immediate or "early" phase allergic reaction is subsequently followed by a more prolonged "late" phase reaction.
• Histamine is an important chemical mediator that causes many of the common allergic symptoms.
• Knowledge of the allergic cascade has resulted in effective treatments for allergy. Future research is aimed at finding new agents that intervene at specific levels of the allergic reaction.