What are some of the differential diagnoses of anaphylaxis?

Carcinoid syndrome is a syndrome may lead on from a carcinoid tumour, which is a tumour of a certain type of cells in the intestine. 5 % of people with carcinoid tumours get carcinoid syndrome, and only if the tumour has spread to the liver. Signs and symptoms include blue-red flushing on the face and neck, abdominal pain and diarrhoea, and there may be heart problems as well. It can be treated by drugs which act against the chemicals these cells make (which ultimately leads to the signs and symptoms). Episodes of flushing and other symptoms can sometimes be mistaken for allergy.

Phaeochromocytoma is a tumour of part of the nervous system. Although they are rare, they can cause symptoms such as flushing, sweating, nausea or vomiting, a fast, slow, or irregular heart rate, as well as shaking.

Loss of consciousness for a short amount of time (syncope) can be caused by several things, the most common cause is the simple faint (known as vasovagal syncope, situational syncope, or neurocardiogenic syncope). Over half the population experience a faint at some point in their lives, particularly during childhood, youth, or pregnancy, and it is caused by insufficient blood flow to the brain. Fainting is a common response to fear, standing for long periods of time, or pain. However, the person who has fainted will usually recover in less than 2 minutes. Conditions where the heart does not beat with a proper rhythm (cardiac arrhythmias) and heart attacks can also cause loss of consciousness. In the case of a heart attack, the person will usually experience a severe pain or tightness in their chest, and possibly their shoulders and left arm as well. If someone experiences a heart attack, you must call for an ambulance. The paramedics will usually give oxygen and drugs to treat it. An abnormal heart rhythm can be caused by damage to the heart, often caused by a heart attack.

Panic attacks can cause fast breathing and a fast heart rate. The fast breathing may also cause light headedness, a tingling sensation, and occasionally loss of consciousness too. People who have suffered from a previous episode of anaphylaxis may get panic attacks if they think they have been exposed to the allergen again.

Acute severe asthma can cause many of the breathing problems seen in anaphylaxis. Asthma is caused by the airways becoming narrow and filled with mucus, making it more difficult to get air in and out of the lungs. Asthma is another type of allergy or atopy, and is dealt with in more detail in another article.

Angioedema, as well as being a feature of anaphylaxis, can have a number of causes, and can cause a blockage in the throat leading to stridor and difficulty in breathing. It is dealt with in more detail in another article.

Anaphylaxis Guide Index:

• Anaphylaxis - Introduction
• What are the signs and symptoms of anaphylaxis?
• How can you recognise anaphylaxis?

• What should be done to treat an episode of anaphylaxis or anaphylactic shock?
• What can cause anaphylaxis?
• What are some of the differential diagnoses of anaphylaxis?