When an insect like a mosquito bites, it injects saliva containing foreign proteins into the skin. The itching sensation begins as the body’s immune system recognizes these proteins as invaders and mounts a defense. This localized immune response involves the release of histamine. Histamine increases blood flow to the area, causing swelling and redness, and it also sends signals to nerve endings, which the brain interprets as the intense desire to scratch.
Immediate At-Home Remedies
Quick relief from the itch can often be found by using simple items already available in the household. Applying a cold compress or an ice pack constricts the blood vessels, reducing swelling and limiting the spread of histamine, while the reduced temperature also temporarily numbs the nerve endings. Concentrated heat can neutralize the proteins responsible for the irritation, though it must be done carefully to avoid burns. A paste made from baking soda and water can also be effective because the alkaline nature of sodium bicarbonate helps to neutralize the acidic compounds in the insect’s saliva. For multiple bites, soaking in a lukewarm bath with colloidal oatmeal can be soothing, as oatmeal contains anti-inflammatory avenanthramides.
Over-the-Counter Topical Treatments
When household remedies are not enough, store-bought treatments can offer targeted relief. Topical antihistamines, such as those containing diphenhydramine, work by blocking the effects of the histamine released at the bite site, reducing the itching sensation. Combining oral and topical antihistamines containing diphenhydramine is generally not recommended. Creams containing hydrocortisone, a mild corticosteroid, are highly effective because they directly reduce inflammation and suppress the localized immune response, which calms the redness and swelling. Skin protectants like calamine lotion create a physical barrier and help to dry out bites, offering a cooling sensation that distracts from the itch.
Managing the Itch-Scratch Cycle
The itching leads to a cycle where scratching the area worsens inflammation. Scratching causes micro-abrasions, releasing more inflammatory chemicals and intensifying the itch, which also increases the risk of introducing bacteria and infection. To manage this cycle, keep the affected area clean by washing it gently with soap and water. Covering the bite with a small bandage serves as a physical reminder not to scratch, especially during sleep. While most bites resolve naturally, excessive swelling, radiating redness, warmth, or pus requires immediate medical attention, as these are signs of infection.
Future Bite Prevention
The most effective way to eliminate itching is to prevent bites. Chemical repellents registered with the Environmental Protection Agency (EPA) are effective and contain DEET, picaridin, or oil of lemon eucalyptus (OLE). DEET creates a vapor barrier that deters insects, and concentrations between 10% and 35% provide adequate protection. Picaridin is another strong repellent option that is nearly odorless and less likely to damage plastics or synthetic fabrics than DEET. Wearing long-sleeved shirts and loose-fitting pants serves as a simple physical barrier, and eliminating sources of standing water around the home reduces the local insect population.