Have you ever experienced itchy, swollen hands and legs immediately following a long walk, hot shower or vigorous exercise? If you know what I’m talking about, you know how uncomfortable it can be to put up with that even for a few minutes.

Now imagine those symptoms going on for hours at a time combined with abdominal cramping, loss of your voice and even life-threatening airway closure.

This type of attack is a daily worry for somebody suffering from hereditary angioedema, a serious and rare immune disorder that is acquired genetically.

Hand with signs of hereditary angioedema

To sufferers of hereditary angioedema, swollen hands could be the onset of a very dangerous medical outbreak.


What causes hereditary angioedema?

Hereditary angioedema (or HAE) is caused by either a lower level or improper function of the C1 inhibitor protein.

The C1 inhibitor is an important protein found in the blood which helps to regulate internal functions like the flow of bodily fluids in and out of cells.

When a genetic disorder causes this protein to be either insufficiently produced or not functioning properly, it can have a major effect on your blood vessels and lead to a seriously life-threatening attack.

These attacks can be set on by sickness, surgery, menstruation in women, dental work or trauma. Pretty much any condition, event, or state that disrupts the body’s usual stasis is liable to cause an attack.


Who suffers from hereditary angioedema?

Anybody, male or female, can receive the trait from a parent. Current estimates for the disorder place its incidence at 1 out of every 10,000 to 50,000 people in the United States of America and Canada, making it a rare disorder.

Approximately 15,000 to 30,000 emergency visits a year are connected with hereditary angioedema. The mortality rate is a moderately-high 15-33% with the majority of deaths coming from swelling in the larynx (edema) or trachea (asphyxiation).


How do I know if I have hereditary angioedema?

Because hereditary angioedema is a genetically dominant disorder, if one of your parents has it you are 50% likely to carry or suffer from the disease as well.

Unfortunately, it has gone unnoticed in previous generations as parents, grandparents or ancestors may have had the condition misreported as simply a premature death due to unknown causes.

Symptomatically, hereditary angioedema is like a prolonged version of hives, with symptoms of an attack including: rapid swelling of feet, face, arms, legs, voicebox, windpipe (trachea) or intestines. There is NO hives associated with this and typically NO itching.

Often, these symptoms increase in intensity as the affected person grows into adulthood.

What happens if I get an attack?

Due to the genetic, autosomal nature of the disease, there is no cure. Treatments regularly used for angioedema (like antihistamines) are ineffective against its hereditary variety.

In case of an attack, treatment is required immediately or the victim’s trachea (windpipe) or voice box (larynx) can swell to the point of closing off, killing them by edema or asphyxiation respectively.

In this event, either a C1 inhibitor concentrate from donor blood or fresh frozen plasma (FFP – which contains the C1 inhibitor that HAE sufferers lack natively) can be used.

Though ineffective as a sustained treatment model, epinephrine (in the form of an epi-pen) can be administered as an acute emergency response to combat an attack.

Long-term treatment models involve either stimulating the synthesis of this necessary protein, or reducing its consumption by other cells and tissues. If attacks are triggered by specific stimuli or traumas, finding ways to avoid these triggers could be crucial as well to an HAE sufferer.

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