Swellings affecting skin, mucous membranes, eyelids, lips, genital organs, hands and feet, burning sensation in arms and legs – is this a case of angioedema?
Our skin is made up of three layers: epidermis, dermis and hypodermis (or subcutaneous layer). Angioedema – also known as Quincke’s oedema or angioneurotic oedema – means accumulations of fluid in the subcutaneous tissue that lead to swelling. Two basic forms of angioedema can be distinguished: mast cell-mediated and bradykinin-mediated angioedema.
Most cases of angioedema that occur spontaneously are mast-cell-mediated (also known as mast cell mediator-mediated). The causes of activation of the mast cells are diverse: e.g. allergic reactions, viral or bacterial infections, medications or even stress factors.
Bradykinin is a tissue hormone that increases vessel permeability. The protein C1-inhibitor regulates the formation of bradykinin. If C1-inhibitor is available in insufficient quantities, if it is deficient or too much of it is consumed, the result is an excess of bradykinin. This also happens if degradation of bradykinin is blocked. This excess leads to angioedema. Subforms of this group are:
Swellings occur in both forms of angioedema, often combined with a feeling of pressure or a burning sensation in different parts of the body, e.g.
In mast cell-mediated angioedema, itchy hives (urticaria) may appear on the body at the same time.
In hereditary angioedema (HAE) swellings frequently occur in the gastrointestinal tract (especially in the small and large bowel), which can result in severe abdominal pains, nausea, vomiting and diarrhoea even lasting several days. Swellings in the airways can be very dangerous. However, life-threatening situations can be averted in most cases because effective medicines are available nowadays.
If the swelling is visible, the clinical diagnosis is relatively straightforward. On the other hand, searching for the cause is often a challenge, which is why it is important for the doctor to question the individual thoroughly when investigating the symptoms. In addition, specific laboratory tests (e.g. measurement of the level of C1-inhibitor) can provide further information to help clarify matters. A symptom diary kept by the sufferer may prove helpful to the doctor when making the diagnosis. This diary should detail the times when the swelling appears and contain information about pain, itching and accompanying symptoms (such as possible skin rashes, joint pains, breathlessness or abdominal pains). Photographs of the swellings are also very useful to the doctor.
If the angioedema is induced by allergy, the trigger should be avoided as far as possible. If a medication is responsible for the reaction, the individual should stop taking the drug. If a bacterial infection or some other illness is the cause, it is important to treat this appropriately.
In most cases – irrespective of the cause – antihistamines and cortisone preparations are used to relieve the symptoms. In the case of life-threatening swellings, these drugs are also used as emergency medication, if necessary combined with an adrenaline pre-filled syringe.
In hereditary angioedema (HAE), the primary aim should also be to avoid the triggers. In addition, there is a possibility of preventive therapy with certain drugs. The protein C1-inhibitor and icatibant (active ingredient) – a bradykinin receptor antagonist – can be used to treat an acute angioedema attack.
In acquired angioedema it is important to ensure that the underlying disease is treated. Similarly in drug-induced angioedema via bradykinin, the drugs that cause the angioedema must be withdrawn. If necessary, they can be replaced by medicines from a different class of active substance.