October 3rd 2016
Are you a mosquito bite magnet?
August 10th 2016
If so, here are the mosquito repellents you need and facts you need to know for keeping the bugs at bay...
Mosquito bites can be the bugbear of many a holiday maker. However, are some people more susceptible than others? According to Dr Anjali Mahto, Consultant Dermatologist and British Skin Foundation spokesperson, the myth of the ‘mosquito magnet’ could indeed be more fact than holiday fiction.
“An estimated 10-20% of people are highly attractive to mosquitoes and consistently get bitten more often than their counterparts,” she explains. “While genetics are thought to count for up to 85% of our susceptibility to insect bites, scientists have a number of ideas as to why some of us are more prone to being ravaged by mosquitoes than others.” Here are the factors which could be making you a walking target...
1. Blood type
Yes it’s true - it seems some people’s blood can in fact be tastier than others, providing the perfect day-end tonic for many a stressed out mosquito. Like honey to a bee, what makes some types more appetising than others? “A large number of the population secrete saccharides or sugars through the skin dependant on their blood type that mosquitoes are able to sense,” explains Dr Mahto. “Studies as early as 1972 suggest that mosquitoes seem to prefer those with Type O blood. Mosquitoes land on skin with Type O blood nearly twice as often as those with Type A. People with Type B blood fall somewhere in between this range.
“We do not know the exact cause for this but study investigators have suggested that those with Type O blood may secrete a certain chemical signal through their skin which may be more attractive to mosquitoes.”
2. Certain toiletries
Like a dusting of chocolate sprinkles on a cupcake, there are certain cosmetics that can pique the taste buds of many a mosquito and make skin all the more bite-prone. “Floral fragrances in perfumes, deodorant and skincare products containing AHAs (alpha hydroxy acids) such as lactic acid, have been shown to attract mosquitoes,” explains Dr Mahto. “It may be helpful to avoid these in your usual day to day skincare if possible.” If there was ever an excuse to streamline our holiday skincare regime or swap floral for woody in the fragrance department, this might well be it.
If toiletries are the sprinkles, than our natural skin bacteria can arguably be seen as the icing. “Large numbers of bacterial species naturally inhabit human skin,” explains Dr Mahto. “Researchers have shown that certain bacterial subtypes present in large numbers e.g. Staphylococcus epidermidis, make individuals more attractive to mosquitoes while others, e.g. Pseudomonas aeruginosa, appear to have the opposite effect. It also seems that having a wide diversity of bacterial types living on the skin makes it less attractive.”
However unlike toiletries, the bacteria are best left alone, with other remedies proving a healthier alternative to reducing our bite vulnerability. “It would not be advisable to start altering the skin’s natural microbiome until we have a better understanding of the processes taking place at the molecular level,” cautions Dr Mahto. “Increasing or decreasing levels of normal commensal bacteria that live on the skin may leave the immune system vulnerable in as yet, unrecognised ways.”
4. Carbon dioxide
As seen with blood type, there are factors that aren’t within our immediate control that can increase our likelihood of mosquito bites. Another is the size of our physique and the effect of it on our breath-size. “Mosquitoes are attracted to exhaled carbon dioxide via receptors in an organ known as the maxillary pulp and can detect their prey from up to 50 metres away,” explains Dr Mahto. “Consequently, those that exhale more gas, i.e. often larger people with increased body habitus, are more likely to get bitten.”
“Aside from carbon dioxide, mosquitoes also rely on other substances, often at close range, to home in on their targets. These include chemicals and compounds secreted in skin and sweat, including lactic acid, uric acid, ammonia, steroids and cholesterol to name a few,” Dr Mahto explains. “Strenuous exercise can result in a build-up of lactic acid which may make individuals more susceptible. Genetic factors are likely be involved in the composition of these substances that are naturally secreted by our bodies.”
Floral fragrances in perfumes, deodorant and skincare products containing AHAs (alpha hydroxy acids) such as lactic acid, have been shown to attract mosquitoes
A cold bottle of beer by the beach is often regarded as the perfect seaside tipple; and it seems mosquitoes couldn’t agree more with its appeal attracting humans and insects alike - to a degree. “Drinking beer may increase the risk of mosquito bites, but the evidence is small,” says Dr Mahto. “Researchers have hypothesised this maybe because beer increases body temperature and the amount of alcohol in sweat. These findings have not been extended to other forms of alcoholic beverages though.” (We’ll order a Mai Tai to go in that case).
It seems a bum deal, but according to Dr Mahto, a baby bump could increase our predisposition to bites. “Pregnant women are more susceptible to bites than their non-pregnant counterparts however, this is likely to be due to the fact that they exhale relatively more carbon dioxide and have a higher resting body temperature,” says Dr Mahto.
8. Dark clothes
It may seem counterintuitive, but it appears the lighter the clothes we wear, the harder it’ll be for mosquitoes to spot us. “Mosquitoes are attracted to dark colours such as black and navy blue as they use vision along with scent to locate their targets,” says Dr Mahto. “It is best to dress in light colours such as white or pastels to reduce the risk of this.”
The best ways to reduce your risk of mosquito bites
1. Mosquito repellent
It seems obvious, but the right ingredients could make all the difference between a bite here and there and a back that's bumpier than Covent Garden Piazza. “Diethyltoluamide (DEET) is probably the most effective chemical repellent available and has a good safety record,” recommends Dr Mahto. “Research has shown that a repellent containing approximately 20% DEET will protect the wearer for about 5 hours. It has a good safety record and weaker formulations of 10% or less are safe to use on infants from the age of 2 months.”
“Other chemical agents available include picaridin and IR3535. They differ slightly in their effectiveness and characteristics but all work in the same way, producing an odour that is unpleasant to mosquitoes.”
If however you’d prefer to go down the DEET-free route, there are other options. “There are a number of plant based chemicals that can offer some protection against mosquito bites,” says Dr Mahto. “They are not as effective as DEET and are not recommended as the only protection in areas that are endemic to malaria though. These include citronella, lemon eucalyptus and neem to name a few.” Lemon eucalyptus has garnered attention as of late after providing particularly positive results in some recent studies. That being said though, it isn't Dr Mahto's first choice and if you are travelling to a high risk malaria-zone, the NHS recommends using mosquito repellent together with the recommended antimalarial tablets for the area and even a mosquito net too to increase defences.
Our pick of the best mosquito repellents
Containing 50% DEET and plant extracts, this high strength mosquito repellent gives noticeably less bug for your buck.
Incognito Insect Repellent, £9.99
If you’d rather go DEET-free, this particular pick containing PMD (recommended by Public Health England and the NHS) packs a punch and is also Vegan Society approved too.
2. Layer up
If we’re the trifle, thin sleeves and light long trousers are our cellophane. While this may be the last thing you’d want to do when it’s baking outside, it could be the perfect partner to the above in case you’re particularly bite inclined.
3. Stick to areas with A/C or fans
Knock ‘em off their feet with the aid of some extra ventilation. Essentially, the harder you make it for them to land on you, the less likely they are to bite you. Plus, you’ll be cooler too.
The best mosquito bite remedies
Sod’s law dictates that no matter how vigilant we are about our mosquito repellent, they’ll find the one millimetre patch of skin that we’ve unwittingly left exposed. Whether on the tip of our toes or our armpit (yep, it’s happened and it was ridiculous), there are steps we can take to deliver some instant post-bite relief. “Insect bites can commonly cause lumps (papules), itching (pruritus), and wealing (urticarial) of the skin. Occasionally, small blisters (bullae) may develop but there are a number of things that can be done to minimise discomfort,” says Dr Mahto. She recommends the following:
1. Antihistamines – “Taking oral antihistamines will relieve the itching and swelling, e.g. cetirizine 10mg once or twice a day.”
2. Mild steroid cream – “Hydrocortisone 0.5-2.5% applied twice daily for a few days can reduce inflammation and itching.”
3. “Calamine lotion - apply to affected areas.”
4. “Cooling the skin, e.g. with a cold compress.”
Our Sense and Sensitivity columnist Judy Johnson is a huge fan of Anthisan Cream, £4.09, antihistamine-wise and Care+ Aqueous Calamine Cream, £2.35, for targeting redness and inflammation. If you’re looking for a natural remedy, Bug Balm, £7.95, could be worth a try due to its high concentration of liquorice root extract, an ingredient touted for its anti-inflammatory properties.
“The bites should usually settle within a few hours to a few days,” says Dr Mahto. “However, it is important to avoid scratching the skin as this increases vulnerability to developing infection at the site of the bite. One of the many functions of skin is to act as a barrier to the outside world. If the skin becomes broken e.g. as a result of scratching, infection is much more likely to develop.
“If you notice pus or discharge in or around the bite, increased pain, redness or swelling or swollen glands, then suspect infection. This may require treatment with oral antibiotics (usually flucloxacillin unless there is an allergy to penicillin), so attend your local doctor.”