Dr. Greene`s Answer:
Cynthia, I now receive many questions each week from around the world. While I can’t possibly answer all of them, each question does make a difference. One of the unforeseen results of this website for me is being able to watch clusters of concerns arise from people who don’t even know each other. This week, I’ve received a flood of questions about mosquito bites. Those fragile little insects can be quite a nuisance. Your daughter Lauren suffers much more than most, and I trust we’ll be able to give her some relief.
Mosquitoes wouldn’t be such a problem if it weren’t for the blood-sucking habits of the females. The males (and often the females) feed on plant nectar, but the females also depend on a blood meal to get the protein they need to mature their eggs, which they then lay on the surface of still water.
Mosquitoes are delicate little insects with long, fragile-looking legs and mouthparts. Appearances deceive, however — the female is equipped with blade-like, piercing mouthparts that enable her to get what she needs for her babies.
Meanwhile, mosquitoes are known to pass blood-borne illnesses from one victim to another. They are a major health hazard and are responsible for the transmission of yellow fever, malaria, dengue fever, encephalitis, and many other serious diseases. In parts of the world where mosquito-transmitted diseases are not common, it is the bite itself which presents the greatest difficulty. More infants and children are bitten by mosquitoes than by any other insect.
When the mosquito stabs her needle-like mouthparts through the skin of her victim, she injects her saliva — teeming with digestive enzymes and anticoagulants. The first time a person is bitten, there is no reaction. With subsequent bites, the person becomes sensitized to the foreign proteins, and small, itchy, red bumps appear about 24 hours later. This is the most common reaction in young children. After many more bites, a pale, swollen hive, or wheal, begins to appear within minutes after a bite — followed by the red bump 24 hours later. This is the most common reaction in older children and adolescents.
With repeated mosquito bites, some people begin to become insensitive again, much as if they had allergy shots. Some older children and adults get no reaction to mosquito bites (unless they go for a long time without being bitten — then the process can start again). Other people, like your daughter Lauren, become increasingly allergic with repeated stings. They can develop blistering, bruised, large inflammatory reactions. For these people, avoiding being bitten is a particularly good idea.
Mosquitoes are attracted to things that remind them of nectar or mammal flesh. When outdoors, wear light clothing that covers most of the body, keeping as much of the skin and hair covered as practical. Avoid bright, floral colors. Khaki, beige, and olive have no particular attraction for mosquitoes. They are also attracted by some body odors, and for this reason they choose some individuals (me!) over others in a crowd. Avoid fragrances in soaps, shampoos, and lotions. All other things being equal, mosquitoes will choose children as their victims rather than adults. Many species of mosquito prefer biting from dusk until dawn. The problem is worse when the weather is hot or humid. Avoid playing outdoors during the peak biting times in your area. It would, of course, also help for one to stay away from still water. People who are highly allergic should avoid vacationing in the Everglades.
The Centers for Disease Control and Prevention (CDC) recommends using an insect repellent on exposed areas of skin. The most effective compounds are DEET (N,N-diethyl meta-toluamide), picaridin, and oil of lemon eucalyptus (Repel). I prefer the safe, non-toxic, plant-based oil of lemon eucalyptus. It does cause irritation if it gets in the eyes, but has otherwise proven safe. It has not been tested, though, on children under age 3. DEET-containing products should not be used on children under 2 months of age. Don’t apply repellents under clothes, or too much may be absorbed. Also, avoid applying repellent to portions of the hands that are likely to come in contact with the eyes and mouth.
30% is the maximum concentration of DEET recommended for infants and children. Lower concentrations have not been shown to be safer. The concentration of an insect repellent affects how long it will last, not how effective it will be when applied.
I prefer gentler insect repellents for children.
Other ingredients, such as IR3535 (Avon-Skin-So-Soft) or combinations of plant oils (Bite Blocker Xtreme or Burt’s Bees All Natural Herbal) can prevent bites, but not as effectively as DEET, picaridin or oil of lemon eucalyptus.
Repellents may not stop mosquitoes from landing — only from biting. If you see mosquitoes on Lauren, the repellents may still be working. If, however, Lauren is being bitten, they are not working.
Some studies suggested that taking thiamine (vitamin B1) 25 mg to 50 mg three times per day was effective in reducing mosquito bites. This safe vitamin was thought to produce a skin odor that is not detectable by humans, but is disagreeable to pregnant mosquitoes (Pediatric Clinics of North America, 16:191, 1969). It seemed to be especially effective for those people with large allergic reactions. Thiamine takes about 2 weeks before the odor fully saturates the skin. Subsequent studies have not found this to be effective. Some say that garlic may work in the same way (except, of course, the odor is detectable by humans), but I have seen no scientific studies supporting this. One recent study was unable to demonstrate that garlic was an effective mosquito repellant (Med Vet Entomol, 2005, 19(1)84-9.)
Once bitten, the mainstays of treatment are cool compresses, antihistamines, anti-itching compounds, and anti-inflammatory medicines. For a cool compress, apply an ice pack wrapped in a towel or soak a washcloth in cold water and press it on the bite. Ask your pharmacist to help you select an appropriate antihistamine for your child. Some are available by prescription only. You might have to balance strength versus drowsy side effects. Zyrtec, a newer antihistamine for children (available over the counter), usually works very well while not being very sedating. Of course, sometimes sedating is not such a bad thing…
The simplest anti-itching compound is a paste made of baking soda and water. Use just enough water to make a sticky paste, and spread it on. Calamine lotion works in a similar way, and usually the effect lasts longer. Other children prefer a menthol lotion such as Sarna. A topical anesthetic containing pramoxine (such as the prescription PrameGel or the over-the-counter Caladryl) can take away the pain and itching.
For the anti-inflammatory part of treatment, ibuprofen (Motrin or Advil) or naproxen (Aleve) can reduce redness, pain, itching, swelling and fever. Topical steroid creams of various strengths can also be useful. Occasionally, reactions to mosquito bites can be severe enough to warrant systemic steroids.
Studies suggest that some natural anti-inflammatory remedies are very effective in some people: oral evening primrose oil (Lancet, 2:1120, 1982) and papaverine (Journal of the American Academy of Dermatology, 13:806, 1985). You might find both of these in a health food store.
Stronger, experimental treatments include thymic hormones, recombinant gamma interferon, ultraviolet radiation, various chemotherapeutic agents, and immunotherapy with mosquito extract (Clinical Pediatric Dermatology, Saunders 1993, Ann Allergy Asthma Immunol, 2007 Sept:99(3):273-80), but I would only consider them if Lauren’s reactions get much worse. Probably they will instead get better over time.
It’s tempting to view mosquitoes as nothing but pests. But as my dear friend Christine Du Bois-Buxbaum reminded me, there are species of fish in the Everglades that need mosquito eggs for their diet. These fish are in turn important to the food chain in their own ways. So, although mosquitoes have been a health problem for centuries, they are also an important part of the Everglades ecosystem and of other natural habitats. Widespread destruction of mosquitoes isn’t necessarily the answer.
Still, buzzing mosquitoes are the bane of warm summer evenings. I’ve given you a lot of different solutions. You won’t need to use them all, but you may need to try several before you find what works best for Lauren. I trust you’ll soon be able to enjoy outdoor time together this summer. And autumn is just around the corner.