Signs and Symptoms of Bed Bug Bites

Bed bug bites typically present as small, itchy, red bumps that are clustered in zig-zag patterns of three or more. The bite marks can appear one day after contact with bed bugs, or can take up to 14 days to show.

Bed bugs (Cimex lectularius) are tiny, nocturnal insects that feed on human blood. These pests tend to live within eight feet from where people are sleeping and often reside in mattresses.

Because their bite marks resemble other insect bites, it can be difficult to tell if you have a bed bug bite unless you find an infestation. Signs of an infestation may include bed bugs or their molted exoskeletons in the edges of the mattress or sheets, blood spots on the mattress, and a sweet, musty odor.

Bed bugs typically don't cause serious harm to people, but their bites can be uncomfortable and infestations can cause stress and insomnia for people. In certain cases, bed bug bites can lead to skin infections or more severe reactions.

Red or Swollen Bumps 

Bed bug bites vary in size and appearance, so it can be hard to differentiate them from other types of insect bites. Some bites may be small, with only a slight raised edge (almost like a pimple). Other bites can grow to be as large as five centimeters in diameter; these are called wheals, and they tend to be extremely itchy.

However, bed bug bites often have a red dot in the center of the bite, surrounded by raised, irritated skin. This is usually considered the original bite mark, which then swelled as a result of your body’s immune response to the insect’s saliva.

Although bed bugs can bite you anywhere during the night, the most common places to find bites are on areas of skin that are typically exposed, like the face and neck, arms, and hands. 

Itching 

When bed bugs bite you, they inject their saliva into your skin while feeding—similar to mosquitoes. The saliva helps the bed bugs get more blood more quickly, but it also causes a mild allergic reaction in most people, creating an intense feeling of itchiness. 

The itchiness can start almost as soon as you’re bitten, or it can take up to days or weeks before you feel itchy. Different people have different tolerances to the proteins in bed bug saliva that cause a reaction. Some people may experience a more severe allergic reaction to the bites, and other people may have no reaction at all.

Clustered Bites 

Bed bugs often travel during their nocturnal feedings, creating a series of bites along one area of the skin. This can cause lines of bites, sometimes in a zig-zag pattern, or clusters of three or more bites in a small area. 

In more severe infestations, it’s also possible to develop a rash or dermatitis (skin inflammation) as a result of bed bugs. This is partly because there are many clusters of bites grouped together and partly due to further skin irritation caused by scratching at existing bites. 

Skin Infections 

Some people may develop secondary skin infections from bed bug bites. Infections can occur when excessive scratching introduces bacteria into the upper layer of the skin. It can also happen if the person is extremely sensitive to bed bugs' saliva.

Signs of a skin infection include blisters, skin tenderness, oozing or pus discharge, intense redness, hives, and potentially fever.

Children are especially vulnerable to secondary infections like impetigo, which is often caused by bacteria like the group A Streptococcus (strep) being introduced through exposed areas of skin. Impetigo is treated with antibiotics, so if you think your child has developed an infection as a result of their bed bug bites, contact their pediatrician or healthcare provider as soon as possible.

Other types of skin infections caused by bed bug bites can be treated with a combination of antihistamines, topical corticosteroids, antiseptics, or antibiotics. It’s important to see a dermatologist or other healthcare provider if you have any signs of a skin infection, especially if you suspect a bed bug infestation.

Anaphylaxis 

In rare cases, some people can experience a severe allergic reaction to bed bug saliva. This is called anaphylaxis, and can present with symptoms like:

• Difficulty breathing
• Swollen tongue
• Increased heart rate

If you experience any of these symptoms, it's important to seek emergency medical attention.

When to Contact a Healthcare Provider 

Most people can treat their bed bug bites at home with over-the-counter antihistamines and corticosteroids, like topical hydrocortisone.

However, if you have a high number of bites, have a rash or dermatitis, or observe signs of a skin infection like redness, swelling, or pus discharge, you should contact a healthcare provider as soon as possible. 

If you are regularly finding bites or other swollen bumps on your skin and are sure you haven’t come into contact with bed bugs, you may want to make an appointment with a dermatologist to rule out other causes for your symptoms.

Finally, if you have bed bug bites and are experiencing any symptoms of anaphylaxis such as trouble breathing, increased heart rate, or oral swelling, you should seek urgent medical care. Anaphylaxis is a life-threatening condition.

A Quick Review 

Bed bug bites often cause intensely itchy, red, and swollen bumps on the skin, and can appear in zig-zag lines or in clusters of three or more bites. The bites can take up to 14 days after contact with bed bugs to appear.

More severe cases of bed bug bites can cause secondary skin infections, so it’s important to avoid scratching your bites as much as possible and make an effort to keep your skin clean. If you experience symptoms of a severe allergic reaction such as difficulty breathing, it's important to seek immediate medical care.