What's the root cause of unexplained swollen lips?

Q I am a 43-year-old man. My lips started to swell about eight months back.

When I woke up to wash up one morning, my lower lip suddenly felt numb and swollen.

The swelling was mild and subsided after a couple of hours. So, I did not pay much attention to it.

A few weeks later, after a dinner at home, my upper lip immediately felt numb and started to swell.

The swelling was more severe than the first time and lasted almost till the next morning.

As I had a homecooked meal with no monosodium glutamate (MSG), I did not connect it with a food allergy.

I consulted a doctor and he suspected it was some type of food allergy. He prescribed oral medication.

The swelling did not appear again for about a month. Then, when I was having seafood with beer one day, my lips started swelling immediately after my meal. I suspected that it was linked to my food.

The next day, I consulted an ear, nose and throat specialist. He did a blood test to see if I am allergic to food such as shellfish and nuts. The results did not indicate any allergy to those types of food.

After that, my lips swelled more and more often. I started to take antihistamine every alternate day and my lips did not swell even when I ate shellfish or consumed alcohol.

However, if I skipped taking the medication, my lips will start to swell every second or third day and it usually happens at night. I do not know what is causing my lips to swell. Is there any way I can find out the root cause and not be dependent on long-term medication?

A What you are experiencing is called angioedema.

Like urticaria or hives (raised, itchy bumps on the skin), it is the result of fluid accumulation in the skin.

But unlike hives, the fluid accumulates in the deeper part of the skin.

Thus, it is associated with some discomfort (the numbness that you described) and it lasts longer than hives, even up to few days. It has a preference for certain parts of the body, such as lips and eyelids.

In severe cases, internal organs such as the tongue and airway can be affected, causing debilitating and even life-threatening situations.

Food allergy can certainly cause angioedema, but this should have happened in your younger days.

Certain naturally occurring or synthetic food ingredients and preservatives can also cause angioedema, but that is difficult to prove.

Certain types of medication can cause angioedema, notably angiotensin-converting enzyme inhibitors - a class of drugs for high blood pressure.

The commonest cause of recurrent angioedema is idiopathic (unknown cause), in which attacks come in various frequencies. Stress and infection are believed to be triggers for these attacks.

Very rarely, angioedema may be associated with serious underlying medical conditions such as lymphoma (cancer of white blood cells called lymphocytes) and systemic lupus erythematosus (an autoimmune condition in which the body's immune system mistakenly attacks healthy tissue).

You may wish to consult a dermatologist to undergo re-evaluation and relevant investigations.

In the meantime, avoid things that may make you more susceptible to developing angioedema, such as alcohol and painkillers like aspirin.

You may continue taking antihistamine on a regular basis to prevent angioedema.

It is possible that you may need to take it for months to years before the condition "burns out" on its own.

DR DERRICK AW, senior consultant at the University Dermatology Clinic at the National University Hospital

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