Insect bites: when to go to the emergency room

• Most insect bites are mild, but some need medical attention; Dr. Vania Tareco of Mass General Brigham explains when to go to the emergency room.

Insect bites and stings are a common but irritating part of life, especially in warmer months. Most bites and stings cause mild symptoms and go away within a few days. However, some need medical attention and can even be life-threatening.

Thousands of people go to the emergency room every year because of insect bites, and around 100 die each year from fatal reactions to bites and stings. In the Dominican Republic in particular, mosquito bites are most common between May and November, during the rainy season.

“Most bites are mild and can be treated at home,” says Vania Tareco, DO, an emergency medicine physician at Mass General Brigham Urgent Care. “However, they can become serious if an allergic reaction or infection develops.” She offers several tips to help you decide when to see a doctor about an insect bite.

When to go to the emergency room for an insect bite

Allergy to mosquito bites is a global public health problem according to the World Health Organization (WHO), with an estimated prevalence of 10% to 20% of the population. More than 3 million people in Latin America and the Caribbean are estimated to have allergic reactions to mosquito bites each year.

Dr. Tareco recommends going to the emergency room immediately if you have any signs of a severe allergic reaction or infection.

Symptoms of an allergic reaction to an insect bite

Signs and symptoms of an allergic reaction include:

• Hives or a rash (often itchy) on other parts of the body, not just at the site of the bite.
• Swelling of the lips, tongue or throat.
• Difficulty swallowing, breathing or speaking
• Abdominal pain or cramps, nausea, vomiting or diarrhoea
• Loss of consciousness, dizziness, light-headedness or confusion.

A larger-than-expected reaction in part of the body (for example, you are bitten on the ankle but your whole leg swells).

“If you have symptoms of an allergic reaction, you should seek emergency care in person immediately,” says Dr. Tareco. “Go to the nearest emergency department or call 911, depending on how severe your symptoms are.” The emergency department can give you antihistamines, corticosteroids, epinephrine (adrenaline) or other treatments to help you breathe.

Even if you have used an epinephrine auto-injector (an EpiPen®), you should seek medical care, says Dr. Tareco. “During an allergic reaction, an EpiPen can make you feel better quickly, but you are at risk of your symptoms coming back,” she explains. “In severe reactions, patients may need additional doses of epinephrine and other medicines. Delaying care could put you at greater risk of complications.”

Signs of an infected insect bite

If you scratch the skin where you have a bite or sting, you can create an opening for bacteria to get in. Infection usually appears a couple of days after the initial bite or sting, and signs include:

• Fever
• Pus
• Red streaks on the skin spreading from the bite area
• Worsening redness, pain or warmth around the bite area.

Another possible infection related to insect bites is ticks and Lyme disease. Dr. Tareco advises seeking medical care if you notice a tick or a bite and:

• A bull’s-eye rash appears (although not everyone with Lyme disease gets this rash).
• You have a fever, headache, neck pain or flu-like symptoms.
• You have widespread joint pain in the days or months after the bite.
• The area is very swollen
• You think a tick has been attached for 36 hours or more.

“It’s very important to start antibiotics as soon as possible if the bite is infected. And if you’ve been bitten by a tick, you should talk to your doctor about whether you should be tested for Lyme disease or receive prophylactic (preventive) treatment.”

If you notice any of these signs or symptoms, call your primary care provider (PCP). Your doctor’s office can recommend next steps and help with any urgent problems. Many Mass General Brigham adult and paediatric primary care practices offer same-day visits, in person and virtually.

When to go to urgent care for insect bites

People with insect bites and stings often do not need the high level of acute care provided in the emergency room. However, you may still want to see a doctor. If you do not have a primary care provider or no appointments are available, you can go to an urgent care centre.

Another useful option is Mass General Brigham Virtual Urgent Care. It is open to all patients aged 3 and over, even if they have never seen a Mass General Brigham provider before. New and existing patients can schedule a same-day or next-day virtual urgent care visit in Mass General Brigham Patient Gateway.

During a virtual urgent care visit, you can upload photos of the insect bite or sting. The care team asks several questions, such as whether you know what bit you, when it happened and what symptoms you have. They quickly determine whether you need immediate in-person care.

“We’ll make sure you’re okay, check you for allergic and infectious symptoms and make sure you’re comfortable and stable,” says Dr. Tareco. “If there is any cause for concern – for example, if we need to check your vital signs or give you medication right away – we’ll tell you exactly where to go for urgent care.”

If you don’t need urgent care, the team can:

• Make a diagnosis
• Recommend strategies to relieve symptoms at home
• Prescribe medication or recommend over-the-counter medicines to relieve symptoms and prevent infection
• Tell you what to look out for and when to seek further medical care.

Treating an insect bite at home

If an insect bite is mildly irritating but you have no serious symptoms, you can usually treat it at home. Dr. Tareco recommends several strategies.

“First, remove any stingers, ticks or insect fragments from your skin. An over-the-counter tick removal tool can be useful,” she says. “If you see remains of a possible foreign body, it must be removed completely. Then clean the skin and disinfect it properly.”

Gently wash the area with soap and water. (Hydrogen peroxide and alcohol can also be used.) Apply a damp cloth, cold water or an ice pack to the area for 10 to 20 minutes to relieve symptoms.

She also notes that “calamine lotion, 0.5% to 1% hydrocortisone cream or a paste made from baking soda mixed with a little water can reduce pain, swelling and redness. Over-the-counter antihistamines, such as diphenhydramine cream, Claritin® and Allegra®, can also help.”

Preventing insect bites

The Dominican Republic’s Ministry of Public Health reports that mosquito-borne diseases such as dengue, chikungunya and malaria remain a significant public health problem in the country.

By epidemiological week 18, ending 5 May 2024, 13,542 cases of dengue, 1,874 cases of chikungunya and 312 cases of malaria had been reported, with the Metropolitan, Enriquillo and Cibao Norte regions the most affected, and children under 15, pregnant women and people with chronic diseases at greatest risk.

The best treatment is to avoid insect bites in the first place. To do so, Dr. Tareco recommends the following precautions:

• Apply insect repellent to your skin and clothing when outdoors. Avoid sweet-smelling products such as perfumes, lotions and deodorants.
• Avoid areas with standing water and always cover rubbish bins, as they can attract insects.
• Avoid going out at dawn and dusk, when mosquitoes and other insects are most active.
• Dress appropriately outdoors. Consider wearing long sleeves, trousers and closed shoes for activities such as hiking or gardening.
• Keep windows and screens in good repair to stop insects getting into your home.
• Keep food and drinks covered when eating or drinking outdoors. Insects are often attracted to them.

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