Hereditary angioedema

The inflammation that hereditary angioedema causes does not present associated itching and may last for 1 to 5 days. These symptoms are developed as a result of the malfunction of certain proteins that help maintain the normal flow of fluids through the blood vessels (arteries, veins and capillaries).

The seriousness of the disease shows a significant degree of variance. Angioedema episodes may be extremely incapacitating and have a serious effect on the patent’s quality of life. When it occurs in the region of the mouth or neck, the sufferer may die of asphyxia if they are not given preventive treatment.

In most cases symptoms start to manifest in childhood and/or puberty and continue throughout adult life.

There are different types of hereditary angioedema and they are classified according to whether or not they present a deficiency of the C1 component of the complement (C1-INH).

Symptoms

Swelling of the subcutaneous tissue in any part of the body, although it is most commonly found in:

• the extremities (hands, fingers, feet or toes)
• the genitals (labia or scrotum or penis)
• the gastrointestinal tract (abdominal pain may be very intense and may be accompanied by vomiting, diarrhoea or abdominal distension)
• the face (lips, eyelids)
• the oropharyngeal region (mouth or upper respiratory tract)

Depending on the affected area, the symptoms may range from local discomfort to invalidity of the affected extremity, discomfort or pain when swallowing, voice changes, loss of voice, or dyspnoea (shortness of breath). 

At one time of their life up to 50% of patients may present an episode that affects the throat, which if not immediately treated could lead to asphyxia.

Who is affected by the disease?

Hereditary angioedema affects people who exhibit a mutation in certain genes, such as SERPING1, F12, PLG, KNG1 and ANGPT1.  As it is a dominant autosomal disease, an affected patient has a 50% chance of passing it on to their children. Given that it is a genetic disorder, it is common to find that more than one member of the family is affected.

Depending on the type of mutation, it may affect men and women equally (types I and II) or women more frequently (HAE-nC1-INH). Cases of hereditary angioedema without C1-INH deficiency are usually associated with hyperoestrogenic states, such as pregnancy or the consumption of contraceptives that contain oestrogens.

Diagnosis

The Allergology Clinic first assesses patients who present with recurring angioedema episodes and cases in which there are family members who also suffer them. Subsequently, a blood analysis is requested to determine the levels of the components of the complement, including the inhibitor of component C1 (C1-INH) and, finally, the diagnosis is completed with a genetic study.

Typical treatment

Treatment depends on the number of attacks, the severity of the symptoms and the degree to which quality of life is affected. Treatment is always on a case-by-case basis and may be acute, which means the subcutaneous of intravenous administration of medication at the time of the angioedema attack, or preventive, to stop attacks occurring so frequently. The latter treatment is usually recommended for the patients who suffer the most episodes. 

Angioedema treatments can be self-administered by the patients.

In the case of surgery, endoscopies, tooth extractions or certain dental procedures, treatment must be given in advance to prevent an attack.

Typical tests

Blood analysis normally forms part of the diagnostic procedure. Depending on the treatment, during monitoring it may be necessary to perform an abdominal ultrasound and draw blood for analysis. 

Prevention

Factors known to possibly trigger attacks should be avoided as far as possible:

• Oral contraceptives with oestrogens
• Stress
• Injuries, knocks and bangs
• Infections
• Angiotensin-converting-enzyme inhibitors (enalapril)