The “breakfast, lunch, and dinner” sign is an indicator of parasites recognized by medicine, and if you’ve woken up with the tell-tale bite pattern it could mean you have bedbugs. and they're feasting on your blood. The lesions appear in this way because of the way bedbugs map the skin looking for the best lunch spots, and how they sometimes get rudely interrupted by scratching humans before reattaching again.
Bedbugs are one of the world’s major pests that love to dine on the blood of humans among other animals. The most common culprits in our homes are Cimex lectularius and C. hemipterus, and once they get in, it can be incredibly difficult to kick them out.
Parasites that subsist on bloodmeals are common across the planet, but bedbugs have earned a special place in the Hall Of Nuisance Fame owing to their preference for humans. Indicators of an infestation include blood spots on your bedding, small brown blobs (that may be poop or squished bedbugs), and a bite pattern known as the “breakfast, lunch, and dinner” sign.
It’s called this because of the way bite mark patterns are grouped together, often in threes. According to a 2018 paper, there are two key theories behind the pattern that aren’t mutually exclusive: mapping, and successive feeding.
“Before feeding, the fleas and bedbugs mark the most favorable skin area using salivary apyrase, an anticoagulant enzyme,” explained the authors. “The enzyme's action itself can already induce local hypersensitivity.”
“Once they have attached to the human´s skin, the arthropods begin their blood meal, which can be interrupted by the host´s sudden movement or clothes friction. When the meal is interrupted, the arthropods soon find another nearby site to feed, which can favor the mechanism of sequential bites.”
The “breakfast, lunch, and dinner” sign isn’t unique to bedbugs, and can also be an indicator of the kinds of fleas that love our pet cats and dogs so much. While an irritating and unpleasant symptom, it’s also a handy way to identify infestations that can be difficult to spot and eradicate.
Bedbugs are famously elusive because they hide when they aren’t feeding. That means during the day there might be little sign of them, but at night they come creeping out from crevices that they can squeeze into thanks to their flat bodies.
Down the sides of couches and chairs, in drawer joins and even inside electrical outlets are all common hiding places according to the United States Environmental Protection Agency. Bed bugs can even hide in furniture, so if you’re having a house treated you should leave your belongings behind unless you want to accidentally provide safe passage to the very parasites you’re trying to eradicate.
If you’re not in the mood for playing extreme hide and seek with a colony of blood-sucking bedbugs, looking out for signs on your bedding and furniture can be the easiest way to detect signs of an infestation. Oh, and don’t forget your breakfast, lunch, and dinner!