Supporting members with allergies
What is an allergy?
An allergy is caused by the body's reaction to a substance that it recognises as "foreign". This foreign substance is called an allergen (antigen), or allergenic substance.
Common allergens include
- Food such as nuts, eggs, milk, fish and shellfish;
- Medications such as antibiotics (penicillin);
- Environmental allergens such as pollen, house dust and animals. Although not an allergen, chemical fumes can exacerbate asthma;
- Insect bites such as from bees, wasps and hornets;
- Other compounds including rubber (latex).
The body responds to an allergenic exposure by releasing chemicals, particularly histamine, which cause inflammation of the body tissues. The amount of histamine, and where in the body it is released, accounts for the different types and degrees of allergic reactions encountered.
The effects of exposure to allergens can be very varied.
Typical reactions include:
- Skin itching or flushing
- Skin wheals (Urticaria, commonly called "hives" or "nettle rash")
- Swelling of the face and tongue
- Itching/watering nose or eyes
- Shortness of breath or difficulty breathing
- Dizziness or light-headedness
- Collapse and loss of consciousness
- Nausea/feeling sick and vomiting
- Stomach cramps
Not all allergies result in someone having all of the above reactions. For example, an asthma sufferer may notice an increase in their wheeziness during the hay fever season from exposure to pollens, and someone with eczema may develop worsening skin rash and itching from a change in their usual environment, e.g. bedding, detergent. However, even these longstanding allergic responses may get dramatically worse with exposure to a high level of allergen.
A sudden exposure to a high level of allergen, or exposure of even small levels of allergen in a very sensitive person, can trigger a massive allergic response resulting in many of the above reactions occurring together. This can be life threatening, and is termed anaphylaxis.
Anaphylaxis can kill very rapidly.
In such individuals the histamine release from exposure to an allergen is massive and wreaks havoc in the body, creating a severe state of inflammation showing itself in many of the reactions listed above. Prompt treatment is vital in stopping the reaction and reversing the problems arising from it. If not, death can occur.
Some people know if they suffer from anaphylaxis, but an anaphylactic reaction can be triggered in someone who has previously never had such a reaction.
Known anaphylaxis sufferers often wear Medic-Alert type bracelets or medallions to warn others of their susceptibility, and their likelihood of having a severe allergic reaction.
Adrenaline, also known as epinephrine, is a medicine that can halt the worsening of symptoms during a severe allergic reaction, and many anaphylaxis sufferers also carry auto-injectors of adrenaline in case of an emergency. Auto-injectors are special penlike injection devices that are designed to inject a fixed dose of adrenaline into the thigh muscle. These are commonly referred to as the EpiPen or AnaPen.