You wake up with a few itchy welts on your arm and don't think much of it. A mosquito, maybe a flea from the dog. By the next morning, the same marks are back in the same spot.
Bed bug bites are easy to miss. They look like other insect bites, and in some people they take days to show up. The Centers for Disease Control and Prevention notes that reactions can take up to 14 days to develop.
Below are eight signs the itchy welts on your skin, or the strange smell in the room, may be coming from bed bugs rather than something else.
Clustered bites in groups of three or more
The clearest skin pattern is a small cluster. The Asthma and Allergy Foundation of America describes groups of typically three or more bites spaced a few centimeters apart.
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The American Academy of Dermatology adds that the bites inside a cluster often form a zigzag shape.
Bite marks arranged in a straight line
The CDC says the marks may be random or appear in a straight line. The pattern forms when a bug feeds in one spot, then moves and bites again on the same stretch of skin.
Red itchy welts on uncovered skin
Bites usually appear on parts of the body left uncovered during sleep. The AAFA points to the upper body, especially the face, neck and arms. The welts tend to be red, slightly swollen and itchy, close in appearance to a mosquito bite.
Marks that only appear days later, or not at all
Most people do not notice bite marks until one to several days after being bitten. The CDC says some reactions take up to 14 days to develop, while others never produce any visible mark.
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The delay is one reason people often blame the wrong insect. Industry research in the trade publication Pest Control Technology has put the share with no reaction close to 30 percent, and higher among adults over 65.
Blisters at the bite site
The AAFA notes that the affected area may swell and a blister may appear. The Cleveland Clinic lists round bumps containing clear fluid as one of the possible reactions.
A blister is a signal to stop scratching and have the spot checked.
Enlarged welts hives or signs of allergy
The CDC says allergic symptoms can include enlarged bite marks, painful swellings at the bite site, and in rare cases anaphylaxis, a severe whole-body reaction.
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The AAFA notes that anaphylaxis requires immediate treatment with epinephrine, a shot of adrenaline used to stop severe allergic reactions.
Signs of a secondary skin infection
Intense itching can lead to excessive scratching and a skin infection, the CDC warns.
The US Environmental Protection Agency lists impetigo and lymphangitis among the infections tied to bed bug bite reactions. Impetigo is a crusting bacterial skin infection, and lymphangitis is an inflammation of the lymph channels.
A bite that becomes tender, red or starts to ooze needs a doctor's attention.
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A sweet musty odor in the room
Not every clue sits on your skin. The CDC lists a sweet musty odor among the signs of a bed bug infestation. The smell comes from chemicals the insects release and is usually noticeable only once an infestation is well established.
If a bite grows, feels painful or shows pus, the CDC and the AAFA both recommend seeing a healthcare provider rather than waiting the reaction out.
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This article is made and published by Aksel Kryhlmand, who may have used AI in the preparation.