Delayed response to allergen, also known as a “late phase reaction,” is an allergic response that occurs several hours after exposure to an allergen. This type of allergic reaction is most commonly seen in people with asthma, eczema, and allergic rhinitis.
Symptoms of a Delayed Response to Allergen
The symptoms of a delayed response to an allergen can vary from person to person, but typically include:
• Skin reactions such as itching, hives, or swelling
• Wheezing or difficulty breathing
• Runny nose or sneezing
• Coughing
• Watery eyes
• Fatigue
• Headache
• Abdominal pain
• Nausea
Causes of a Delayed Response to Allergen
The cause of a delayed response to an allergen is not fully understood, but it is believed to be the result of a complex interaction between the body’s immune system and the allergen. When an allergen is encountered, the body’s immune system produces antibodies (also known as immunoglobulins) which then bind to the allergen. This triggers a reaction in the body’s cells which results in the release of various chemicals, including histamine. Histamine is the chemical responsible for the allergic symptoms.
Treatment for a Delayed Response to Allergen
Treatment for a delayed response to an allergen usually involves avoiding the trigger allergen and using medications to reduce the symptoms. If the allergen is known, avoiding it can help to reduce or prevent the reaction. If the allergen is not known, then an allergy test may be needed to identify the cause.
Medications such as antihistamines, corticosteroids, and bronchodilators may be used to reduce the symptoms of a delayed response to an allergen. In severe cases, an epinephrine injection may be needed to treat a severe allergic reaction.
In some cases, immunotherapy may be recommended to desensitize the body to the allergen. This involves regularly exposing the body to small amounts of the allergen in order to reduce the body’s sensitivity to it.
