Recognising severe allergic reactions

In Greek, the word “anaphylaxis” means “without guarding.” In simple terms, it is an allergic reaction that happens suddenly, affects various systems in the body, and may be fatal. It doesn’t take much to trigger anaphylaxis. A peanut or a hornet sting can cause it.

Dr Amir H.A. Latiff, a consultant paediatrician, clinical immunologist and allergist, and president of the Malaysian Society of Allergy & Immunology (MSAI) explains further.

What is anaphylaxis?

It is a severe, life-threatening hypersensitivity reaction that may involve an allergy mechanism or a non-allergy cause. Traditionally, anaphylaxis refers to an immediate type of hypersensitivity reaction known as IgE-mediated anaphylaxis. But now it also includes nonallergic anaphylaxis.

How common is it among young Malaysian children?

The actual rate among young children in Malaysia and the world is not known, but it is suggested to be around 0.05-2% overall, and the rate has been increasing over the last two decades. Apparently, this increasing trend is occurring more in the younger population than in adults.

What are some of the things that can cause anaphylaxis?

Food, drugs, insect stings, latex and biologics (medications produced through biological processes involving DNA technology) can cause anaphylaxis. Anaphylaxis can also be exercise-induced (especially when associated with food). At times, the cause is unknown. But the majority of anaphylaxis in children is caused by food, including cow’s milk, egg white, soya, and wheat, while in adolescents, peanut, tree nuts and seafood (both fish and shellfish).

What happens inside the body during an anaphylactic attack?

Chemicals are released from mast cells (a type of cell found in connective tissues) and basophils (a type of white blood cell), leading to symptoms and signs of an anaphylactic attack. These chemicals which include histamines, leukotrienes, interleukins, chemo-attractants, proteoglycans, and neutral

proteases, not only directly affect organs such as the skin, respiratory, gastrointestinal and cardiovascular systems, but also cause other reactions, thus worsening the condition.

Are there any early warning signs of an impending anaphylactic attack?

The majority of anaphylaxis involves the skin, which is presented as redness, itchiness and hives (with or without swelling of the deep, soft tissues such as those found in the eyes, mouth or throat). These may be early warning signs. And when another system, typically the respiratory system, or at times the

gastrointestinal or cardiovascular system is involved, then anaphylaxis is diagnosed. But in some cases, the skin is not affected. For example, nausea and itchiness in the oral cavity, which then rapidly progress to potentially fatal conditions where the respiratory system is involved.

What does a child feel during an anaphylactic attack?

Signs and symptoms of anaphylaxis involve various body systems:

Skin: Hives and angioedema (e.g. swollen face), flushing, itchiness.

Respiratory system: Wheezing, shortness of breath, upper airway/ throat obstruction (choking), rhinitis, stridor (noisy breathing).

Gastrointestinal system: Nausea, vomiting, diarrhoea, cramping (abdominal pain).

Cardiovascular system: Dizziness, fainting spells/collapse, low blood pressure, loss of consciousness, chest pain (may manifest as a heart attack).

What must parents do when the child gets anaphylaxis?

Parents must follow the written anaphylaxis action plan which includes immediate self-treatment and quickly calling for emergency medical assistance. The child must be placed in a lying position with his legs raised, and never be made to sit or stand up during the attack and throughout the treatment.

Medication would include immediate injection of adrenaline, followed quickly by treatment in a hospital’s emergency department.

Can anaphylaxis be prevented? If yes, what are the measures that parents can take?

An accurate diagnosis which includes the child’s clinical history, and supporting allergy diagnostic tests (blood, skin, and challenge tests) to find the cause of the anaphylaxis, need to be done. Identifying the cause will enable avoidance and prevent further anaphylactic attacks. This is followed by a written anaphylaxis action plan with medications for self-treatment, such as the use of self-injectable adrenaline in the event of an accidental exposure leading to anaphylaxis.

Anaphylaxis is a serious medical problem that can be life-threatening. Thus, one should remember the 3Rs of anaphylaxis:

- Recognise the symptoms.

- React quickly with intramuscular adrenaline injection.

- Review by an allergy specialist after an anaphylactic attack to identify the cause and to prevent future recurrence. – Article courtesy of the Malaysian Society of Allergy & Immunology