How to Check for Bed Bugs: What to Look For and Where to Find Them

You found something on your mattress. A tiny dark spot. Maybe a few of them along the seam. Or maybe you woke up with a line of small red welts on your forearm that weren’t there last night. Your first thought is a mosquito bite — but it’s March, and there are no mosquitoes.

So you Google it. And now you’re here, wondering if you have bed bugs.

This guide will walk you through exactly how to check — what to look for, where to look, and what to do if you find them. No panic, no fluff. Just the information you need to know right now.

What bed bugs actually look like

Adult bed bugs are about the size and shape of an apple seed — flat, oval, reddish-brown. After feeding, they swell and turn a darker red. They’re visible to the naked eye, but they’re good at hiding, so you’ll usually find evidence of them before you find the bugs themselves.

Nymphs (juveniles) are smaller, translucent to pale yellow, and much harder to spot. Eggs are tiny white ovals, about 1mm long — roughly the size of a pinhead. You’ll usually find them in clusters in crevices.

The five signs to check for

1. Dark spots on your mattress

This is usually the first thing people notice. Bed bug fecal stains look like someone dotted the fabric with a fine-tipped marker — small, dark brown or black spots, often in clusters. Check the mattress seams first, then the piping, tags, and any folds in the fabric. Pull the fitted sheet back and look along the top edge of the mattress where it meets the box spring.

2. Blood stains on your sheets

Small reddish-brown smears on your sheets or pillowcases. This happens when you roll over a bed bug that just fed — you crush it and the blood spreads. The stains are usually small (the size of a pen tip to a small coin) and may not appear every night.

3. Bite marks in patterns

Bed bug bites often appear in lines or clusters — sometimes called “breakfast, lunch, and dinner” because the bug feeds at multiple spots as it moves along your skin. They’re small, red, and itchy, usually on exposed skin: arms, shoulders, neck, face. Not everyone reacts to the bites, though — about 30% of people show no visible marks at all, which means you can have bed bugs and not know it from bites alone.

4. Shed skins

Bed bugs moult five times before reaching adulthood, leaving behind translucent, shell-like skins. You’ll find these in the same places the bugs hide — mattress seams, behind the headboard, in the cracks of the bed frame. If you’re finding shed skins, it means the colony has been there long enough for bugs to grow through multiple life stages.

5. A musty smell

A heavy bed bug infestation produces a distinctive sweet, musty odour — often compared to overripe raspberries or coriander. If you can smell it, the infestation is significant. Most people won’t detect this at earlier stages.

Where to look (beyond the mattress)

Most people check the mattress and stop there. Bed bugs hide in a lot of places you wouldn’t expect:

• Headboard: Especially if it’s mounted to the wall — the gap between the headboard and the wall is prime hiding territory. Pull it away from the wall if you can.
• Bed frame joints: Where rails meet posts, any screw holes, any crack or crevice in the frame.
• Box spring: Turn it over. Check the fabric on the underside, the staples, the corner guards, and the wooden frame inside. This is one of the most common hiding spots.
• Nightstands: Inside drawers, behind the unit, any cracks in wood joints.
• Baseboards: The gap between the baseboard and the wall, especially near the bed.
• Electrical outlets: Behind outlet covers near the bed. Bed bugs love the warm, dark space behind electrical plates.
• Curtain folds: The pleats and hems of curtains near the bed.
• Furniture seams: If you have upholstered chairs or a couch in the bedroom, check the seams and cushion zippers.

A good rule: if a credit card can fit in the crack, a bed bug can hide there.

How to do a thorough check

You’ll need a flashlight and something flat like a credit card or butter knife to probe crevices. Here’s the order:

1. Strip the bed completely. Check each piece of bedding as you remove it.
2. Inspect the mattress — every seam, tag, and fold. Top, bottom, sides.
3. Flip or tilt the mattress to check the box spring. The underside fabric is a favourite hiding spot.
4. Examine the bed frame — joints, screw holes, cracks, any wood-to-wood contact.
5. Pull the headboard from the wall. Check the back surface and the wall behind it.
6. Check nightstands, baseboards, and outlet covers within 1-2 metres of the bed.
7. Use your flashlight at an angle — the shadows help reveal bugs and droppings that are hard to see under direct light.

The whole process takes about 20 minutes. If you find even one of the signs listed above, you likely have bed bugs.

What to do if you find them

First, don’t panic. Bed bugs are not a sign of a dirty home — they hitchhike in on luggage, used furniture, clothing, and from neighbouring units. They are equal-opportunity pests.

Second, don’t start spraying things. Store-bought sprays kill the bugs they touch but scatter the rest deeper into your walls and furniture, making professional treatment harder and more expensive.

Here’s what actually helps:

• Bag all your bedding and clothes from the affected room. Wash everything on hot (60°C+) and dry on high heat for at least 30 minutes. The heat kills bed bugs at all life stages.
• Don’t move furniture or mattresses to other rooms — this spreads the infestation.
• Don’t sleep in a different room. The bugs will follow your CO2 trail to wherever you sleep, and now you’ve spread them further.
• Call a professional. Bed bug treatment — especially heat treatment — is one pest problem where DIY almost never works. The bugs hide in places you can’t reach, and missing even a few eggs means the cycle starts over in 2-3 weeks.

Why heat treatment works

Professional heat treatment raises the temperature of your entire room to above 50°C and holds it there for several hours. At that temperature, bed bugs die at every life stage — adults, nymphs, and eggs. No chemical spray penetrates deep enough to reach eggs hidden inside mattress cores, behind baseboards, or inside wall outlets. Heat does.

Most heat treatments resolve the problem in a single visit. It’s more expensive upfront than chemical sprays ($300-800 per room in the GTA), but when you factor in the cost of multiple failed chemical treatments, the math usually favours heat.

When to call a professional

If you found any of the five signs described above, call sooner rather than later. A small bed bug colony can double in size every 16 days. What costs $300 to treat today might cost $1,200 next month.

We offer same-day bed bug inspections and heat treatment across the GTA — Toronto, Brampton, Vaughan, Mississauga, Scarborough, and beyond. The inspection is straightforward, the quote is upfront, and if you need treatment, we can usually do it the same day.