Angioedema is a swelling underneath the skin. This is usually reaction to a trigger such as something you are allergic to or a medication.  In normal cases this condition is not serious. But for some people this can be a recurring problem. Also there are very occasionally cases when it is life – threatening condition if it affects the breathing. Treatment of angioedema can usually keep the swelling under control.
Symptoms of angioedema
The main symptom of this condition is swelling that usually develops below the surface of the skin. Here are the most common symptoms of angioedema:
Swollen skin: The swelling which is caused by this condition can develop suddenly or it can come on gradually over a few hours. Normally, this symptom lasts a few days. The swelling most often affects the: genitals, lips and tongue, area around the eyes, feet and hands. There are some rare cases when the inside of your throat or bowel can be affected.
Rash: Often, the swelling occurs with a raised and itchy rash which is known as hives (urticaria). This rash will usually settle in a few days. Otherwise, the skin over the swelling may feel tight and painful but it looks normal.
Other symptoms: There are less common symptoms of angioedema which are including:
- Feeling sick
- Tummy (abdominal) pain
- Red, irritated eyes (conjunctivitis)
- Difficulty breathing
If you have episodes of swelling that affect your skin or lips and you are not certain of the cause, then you should talk with your doctor about this problem. You may need to make some tests to determine the cause for angioedema.
Causes for angioedema
This condition can have several different causes but in many cases the exact cause of it is not known. Here are some of the main causes of angioedema:
Allergies: In many cases angioedema is result of an allergic reaction. This is where our bodies mistake a harmless substance such as a certain food, for something dangerous. It releases chemicals into our bodies which are attacking the substance and this lead to swelling of the skin. Allergic angioedema is angioedema caused by allergies.  This condition can be triggered by an allergic reaction to:
- Latex which is a type of rubber used to make medical gloves, balloons and condoms 
- Insect bites and stings – particularly wasp and bee stings
- Some types of medication – including some antibiotics, aspirin and non – steroidal anti – inflammatory drugs (NSAIDs) such as ibuprofen [3,6]
- Certain types of food – particularly nuts, shellfish, milk and eggs [4,7]
Genetics: There are rare cases when angioedema is caused by a genetic fault which you have inherited from your parents. This fault affects the gene responsible for the production of a substance called C1 esterase inhibitor. If you do not have enough of this, then your immune system occasionally can “misfire” and it can cause angioedema.  The swelling can happen randomly or it can be triggered by:
- Certain medications such as contraceptive pill
- Surgery and dental treatment
- An injury or infection
Medication: There are some medications which can cause angioedema even if you are not allergic to the medication. The swelling can happen soon after you have started taking a new medication or possibly months or even years later. [3,6] Here are medications which can cause angioedema:
- Angiotensin – 2 receptor blockers (ARBs) such as andesartan, irbesartan, losartan, valsartan and olmesartan – another medication used to treat high blood pressure
- Ibuprofen and other types of NSAID painkillers
- Angiotensin – converting enzyme (ACE) inhibitors such as enalapril, lisinopril, perindopril and rampiril which are used to treat high blood pressure
Unknown cause: There are some cases when it is not known the real cause for angioedema. There is one theory in which is said that an unknown problem with the immune system may cause it to occasionally misfire. There are certain triggers which can lead to swelling such as
- Strenuous exercise 
- Hot or cold temperatures
- Minor infections anxiety or stress 
 Tarbox JA, Bansal A, Peiris AN. Angioedema. JAMA. 2018;319(19):2054.
 Binkley HM, Schroyer T, Catalfano J. Latex allergies: A review of recognition, evaluation, management, prevention, education, and alternative product use. Journal of Athletic Training. 2003;38(2):133–40.
 Kalambay J, Ghazanfar H, Martes Pena KA, et al. Pathogenesis of drug induced non-allergic angioedema: A review of unusual etiologies. Cureus. 2017;9(8):e1598.
 Steiner UC, Kolliker L, Weber-Chrysochoou C, et al. Food as a trigger for abdominal angioedema attacks in patients with hereditary angioedema. Orphanet Journal of Rare Diseases. 2018;13: 90.
 Banday AZ, Kaur A, Jindal AK, et al. An update on the genetics and pathogenesis of hereditary angioedema. Genes & Diseases. 2020;7(1):75-83.
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 Kivity S, Sneh E, Greif J, et al. The effect of food and exercise on the skin response to compound in patients with food-associated exercise-induced urticaria-angioedema. Journal of Allergy and Clinical Immunology. 1988;81(6):1155-8.
 Savarese L, Bova M, De Falco R, et al. Emotional processes and stress in children affected by hereditary angioedema with C1-inhibitor deficiency: a multicenter, prospective study. Orphanet Journal of Rare Diseases. 2018.