BERNAMA/DPA – It could be a perfect day if not for the mosquitoes by the lake, eagerly feasting on you, or the bees and wasps in the field, ready to sting if you dare walk barefoot.
We consulted an allergist to understand what happens when an insect bites or stings, and how to alleviate the resulting symptoms.
HOW DOES THE BODY REACT TO INSECT BITES OR STINGS?
Female mosquitoes bite because they need the protein in blood to develop eggs.
To draw the blood freely, “they secrete saliva into the bite site containing substances that prevent clotting”, said director of the Department of Dermatology and Allergology at the University Hospital of Giessen and Marburg in Germany Dr Thilo Jakob.
Mosquito bites are bothersome because humans are allergic to some of the proteins in mosquito saliva, which actives mast cells – a type of white blood cell – in response.
“They’re under the skin and part of our immune system,” Dr Jakob said.
These cells release chemicals such as histamine, widening blood vessels to facilitate the arrival of immune system agents, as well as causing inflammation and itching.
WHAT ABOUT THE STINGS OF BEES OR WASPS?
They’re not aimed at tapping our blood, but at protecting themselves and/or their colonies.
“They inject venom into our skin, their goal being that we leave them alone,” said Dr Jakob.
Because the venom is a substance foreign to our body, there’s an immune reaction here too.
You feel a sharp pain, and the sting site reddens, swells and itches.
HOW SHOULD YOU TREAT A BEE OR WASP STING?
If the stinger is still stuck in your skin, you’ve been stung by a bee.
The Berlin-based Health Knowledge Foundation recommends removing it as quickly as possible.
You can find a helper in your wallet: Using the edge of a plastic card, carefully scrape off the stinger.
It’s important not to squeeze the sting site with your fingers.
Otherwise, you could put pressure on the venom sac, which may still be attached, and thereby inject more venom into your skin.
Next, you should cool the affected area, which helps to slow the spread of the venom.
It’s also a good idea to disinfect the site.
Getting stung in your mouth by a bee or wasp is serious and cause to call your local emergency number.
Severe swelling of your tongue or oral mucosa can result in life- threatening difficulty in breathing.
It’s essential to cool the area until help arrives, e.g. by sucking on an ice cube or wrapping a cold compress around your neck.
CAN SPIT ALLEVIATE THE SYMPTOMS OF INSECT BITES AND STINGS?
Yes, but not because of any special substances it contains.
“Saliva is nothing more than a fluid you’ve always got with you, and which cools the sting,” explained Dr Jakob.
The cooling effect comes from the evaporation of moisture on the skin, dissipating heat to the environment.
Cooling inhibits the inflammation that results from insect bites and stings, and inflammation is what’s behind their unpleasant symptoms.
A cooling effect incidentally, is what many home remedies for insect bites and stings have in common, be it the application of cucumber slices, white cabbage leaves, quark or onions.
Caution should be exercised in regard to onions though, advised Dr Jakob, as their acidity can burn the skin.
“We’ve seen patients who put a thick bandage filled with onion slices on their skin and leave it there for 24 hours,” he said.
This is too much of a good thing.
WHAT ELSE HELPS?
If a mosquito bite is still fresh, the application of heat with an electronic heat pen can ease itching.
Pressed against the skin, the device gives off temperatures of 50 degrees Celsius or more.
“This is meant to deactivate the proteins that the mosquito has secreted into the skin,” Dr Jakob said.
What’s more, the slight pain caused by the pen covers up the itch as it were, since both signals are transmitted over the same nerve fibres.
Applying an antihistamine on the skin can bring relief as well.
Antihistamines are a class of medications that commonly treat allergy symptoms.
“I recommend an antihistamine gel, since it also cools,” he said.
SCRATCHING THE BITE OR STING SITE CLEARLY ISN’T GOOD. BUT WHY?
You might end up with a skin infection if you do, Dr Jakob warned.
“Bacteria could settle and multiply in skin that’s been scratched open, preventing the bite or sting from properly healing.”
If you think you may have a skin infection, you can get advice at a pharmacy, where over the-counter antiseptic creams are available.
And if you do have an infection and it doesn’t get better, Dr Jakob advises seeing a dermatologist. Consulting a doctor is also advisable if redness around the bite or sting site continues to spread, and is perhaps accompanied by fever and chills.
This can indicate erysipelas, a type of skin infection caused by Streptococci bacteria.
“It’s rare, however,” he said. “But when it does occur, it requires medical treatment.” – Ricarda Dieckmann
