Learn about symptoms and causes of insect bites and stings, self-help treatment options, medication and when to seek medical help.

What are insect bites and stings?

An insect bite occurs when an insect causes a break in a person’s skin to feed. An insect sting occurs when an insect pierces the skin with a body part (stinger) and injects venom. Such insects usually sting as a means of self-defence.

Most insect bites and stings only cause minor skin irritation. Insect bites usually cause itch, while stings tend to be more painful than bites. 

Insect bites rarely cause serious allergic reactions. Some people who are allergic to insect stings can develop serious or life-threatening reactions.

What are the possible causes of this condition?

Insect bites are commonly caused by mosquitoes, bedbugs, ticks or fleas.

Mosquitoes tend to breed in dark places and stagnant water. The Aedes mosquito (which has black and white strips) is most active at dawn and dusk. A bite from an infected Aedes mosquito can cause viral infections such as dengue or Zika.

Bed bugs usually hide in bedding, linen and furniture during the day, and bite humans at night. Bed bugs can be a common problem when travelling as these insects can latch onto luggage, clothing or other personal items.

Ticks or fleas feed on the blood of animals and humans. Humans are often bitten when living with pets which are infested with either ticks or fleas.

Insect stings are commonly caused by bees, wasps or hornets.

Bees, wasps or hornets inject venom into the skin when they sting. Generally, bees leave their stingers in the skin when they sting, while wasps and hornets do not.

What are the symptoms of insect bites and stings?

The symptoms of this condition can include the following:

• Mosquitoes: raised pink bumps on the skin with itch at bite site
• Bedbugs: small bite marks typically appearing in a straight line, with intense itching
• Ticks: raised red bumps on the skin with itch at the bite site
• Fleas: small itchy red bumps often grouped together
• Bees: swelling/redness, pain, itch at sting site (stinger may be present in the skin)
• Wasps or hornets: swelling/redness, pain, itch at sting site

Insect bites or stings usually clear up in a few days without treatment. 

Occasionally some people may develop a severe allergic reaction after an insect bite or sting. 

Symptoms of a severe allergic reaction include:

• Difficulty in breathing
• Swelling of other parts of your body, other than bite or sting site 
• Itchy skin rashes over the whole body
• Dizziness
• Fast heart rate
• Nausea, vomiting, or abdominal pain

If you experience any of these symptoms, seek medical attention immediately.

What can I do to treat insect bites and stings?

Insect bites and stings can be treated in the following ways and you can approach your pharmacist to get the following medications. 

• Topical anti-inflammatory products to bring down swelling, pain, or itch (e.g. Hydrocortisone cream)
• Local anaesthetics to numb pain and itch (e.g. Lidocaine or Lignocaine cream or ointment)
• Topical anti-itch products (e.g. Calamine lotion)
• Oral antihistamines to reduce swelling and itch (e.g. Loratadine or Cetirizine tablets or liquids)
• Oral pain relievers (e.g. Paracetamol or Ibuprofen tablets or liquids)

When do I need to see a doctor?

Although insect bites and stings can be treated without a doctor’s consultation, there are times where the condition might be more serious. 

If your condition does not get better in a few days or gets worse, you should see a doctor. You should also see a doctor if you experience any of the following:

• Allergic reaction to a bite or sting 
• Previous allergic reaction to a bite or sting
• Infection of bite or sting site (e.g. pus found on bite or sting site or if fever develops)
• Bite or sting site becomes more swollen or red
• Feeling unwell after a bite or sting (e.g. flu-like symptoms develop or swollen glands)
• Been stung at your mouth, throat or near the eyes
• Been stung multiple times
• Previous history of being stung

What else can I do to manage this condition?

Other than using medications to treat the condition, insect bites and stings can also be managed by the following methods:

• If there is a stinger in the skin, remove it as soon as possible by gently scraping it off with your fingernail or the edge of a card. Do not pinch the stinger out with your fingers or tweezers as this may cause the venom to spread
• Wash the bite or sting site with soap and water
• Apply a cool compress to the bite or sting site using a clean cloth with cold water
• Avoid scratching bite or sting site (keep fingernails short)
• Avoid wearing rough or irritating clothing over the bite or sting site

The following are some suggestions to prevent insect bites or stings from happening again:

• Cover exposed skin as much as possible with clothing and socks
• Apply insect repellent (e.g. DEET, Picaridin, Lemon Eucalyptus oil) according to product recommendations
• Mosquitoes:
  • Clear stagnant water to reduce breeding areas
  • Reduce time outdoors during dawn and dusk to prevent bites
• Bed bugs:
  • Wash bedding, linen or clothing in hot water, or dry them at high heat to kill bed bugs and their eggs
  • Vacuum home regularly, including furniture to remove bed bugs and their eggs
  • Clean up clutter at home to reduce breeding spots
  • Contact a professional pest control company to clear the infestation
  • When travelling:
    • Check hotel room (e.g. mattress, linen, and headboard), and request for another room if you find signs of bed bugs
      • Signs of bed bug infestation include:
        • Specks of blood
        • Blackish specks (bed bugs’ droppings)
        • Shell-like remains (bed bugs shed their outer shell as they grow)
• Ticks and fleas: treat infested pets
• Bees, wasps, and hornets: 
  • Do not apply perfume or scented lotions when spending time outside (e.g. gardening, picnic, or barbeque) to avoid attracting them
  • Cover all food so as not to attract them
  • Contact a professional pest control company to clear any nests near your home

Disclaimers

This article is jointly developed by members of the National Medication Information workgroup. The workgroup consists of cluster partners (National Healthcare Group, National University Health System and SingHealth), community pharmacies (Guardian, Unity and Watsons) and Pharmaceutical Society of Singapore. The content does not reflect drug availability and supply information in pharmacies and healthcare institutions. You are advised to check with the respective institutions for such information.

The content above is solely for informational purposes only and is not intended as a substitute for the advice provided by your physician, pharmacist or other healthcare professional. You should not use the information for diagnosing or treating a health problem or disease, or prescribing any medication or other treatment. Always speak with your physician, pharmacist or other healthcare professional before taking any medication or supplement, or adopting any treatment for a health problem.