Mosquito bites: resisting the urge to scratch

We filled you in last Wednesday on the most effective mosquito repellents. Today: What to do if the blood-thirsty bugs still manage to chomp on your hide.

Don't scratch mosquito bites — they'll just get worse. You already knew that, but how do you avoid scratching when the itch is driving you crazy?

If the mosquito hordes of summer consider you a tasty tidbit, even with repellents, you could find yourself in the market for a good itch fighter. Several commercial products and home remedies may help.

First, though, this advice from experts: Keep your fingernails and your children's trimmed and clean to help prevent infection if scratching does occur.

Here are some possible anti-itching aids:

Commercial products

They come as creams, lotions, gels, sprays, patches and pills. Some, such as Bite Relief, come in pen-shaped containers with a dispensing point to rub directly on the bite.

Most important, though, are the active ingredients, intended to reduce itching, swelling, pain or infection. Some are quite effective, others less so. Look for active ingredients on the label, along with instructions and precautions. Some advise against use on infants.

The following active ingredients are most likely to offer relief, some experts say, though the responses of individual users may vary:

Hydrocortisone (including Aveeno, Cortizone-10, Cortaid). Reduces itching by constricting blood vessels. Available in many brands.

Calamine (several brands, such as by Band-Aid). Also works by constricting vessels, but is probably less effective than hydrocortisone, says Allan Ellsworth, University of Washington professor of pharmacy and family medicine.

In addition to brand-name products, you can buy less-costly generic calamine lotion.

Like hydrocortisone and calamine, a cold, wet washcloth placed over a bite also constricts vessels and can relieve itching at least briefly, Ellsworth said.

Antihistamines (best known: Benadryl). These come in topical and oral forms and vary in effectiveness. Overall, Ellsworth believes hydrocortisone is more effective than antihistamines against itching.

Some oral antihistamines cause drowsiness. Unfortunately, says Ellsworth, the ones that make you sleepy are the ones that best work against itching. "Nonsedating ones are no good for itch."

The sedating, but more effective, products are generally available over the counter, the nonsedating ones by prescription.

Ellsworth favors oral antihistamines over topical ones. He said some people develop sensitivity to topical antihistamines, which contain an ingredient related to certain anesthetics, including dental Novocaine. As a result, he said, they could have an allergic reaction to Novocaine in the dentist's chair.

For the same reason, Ellsworth advises against anti-itch products containing benzocaine — Bite Relief and others — which are not antihistamines, but pain relievers. He said benzocaine also is related to Novocaine.

Home remedies

Even though commercial hydrocortisone products get the vote of our pharmaceutical expert, many vouch for home remedies as well. Applying these to bites may help fight the itch, though scientific data is skimpy:

• Soap or ice.

• A paste of baking soda and water or vinegar, or meat tenderizer and water or vinegar.

• A wet Alka-Seltzer tablet.

• Witch hazel, available in bottled form.

Judith Blake: jblake@seattletimes.com.