How to Identify Bed Bugs: Signs, Bites & Where They Hide

What Do Bed Bugs Look Like?

Adult bed bugs are small, flat, wingless insects belonging to the species Cimex lectularius. When unfed, they measure approximately 5–7mm in length — roughly the size of an apple seed — and have an oval, flattened body shape with a reddish-brown colour. After feeding on blood, the body becomes more elongated and darker red, often appearing swollen. Many people's first instinct when checking for bed bugs is to look for movement, but bed bugs are most active at night and can remain perfectly still and hidden during daylight hours.

Young bed bugs, called nymphs, go through five developmental stages (instars) before reaching adulthood. They begin at approximately 1.5mm — barely visible to the naked eye — and are nearly translucent or white-yellow in colour when unfed, which makes them extraordinarily difficult to spot against light-coloured bedding or mattress fabric. After feeding, nymphs turn a bright reddish colour. Because nymphs are so small and light-coloured, many bed bug infestations go undetected at the early stage, which is why knowing the other signs of infestation is so important.

Bed bugs have six legs, two antennae, and no wings — they cannot fly or jump, which means they spread by crawling or hitchhiking on luggage, clothing, and second-hand furniture. Under a magnifying glass, bed bugs have a distinctly segmented abdomen and small, compound eyes. They are often confused with other small insects — carpet beetles, bat bugs, and booklice are common misidentifications. If you are unsure whether what you have found is a bed bug, do not attempt treatment before confirming the pest type, as bed bug treatments differ significantly from general insect control.

The image below shows a bed bug next to an apple seed for size reference — this comparison is one of the most reliable quick checks. If the insect you have found is roughly apple-seed-sized, flat, oval, and reddish-brown, there is a meaningful chance it is a bed bug and professional inspection is warranted.

Size comparison: adult bed bug (left) and apple seed (right) — both approximately 5mm. Image for identification reference.

Common Signs of a Bed Bug Infestation

Beyond spotting the insects themselves, bed bugs leave behind a consistent set of physical evidence — learning to recognise these signs of bed bugs is often faster and more reliable than trying to find the bugs directly.

Dark Spots and Staining on Mattresses and Bedding

Bed bug excrement appears as small, dark reddish-brown to black spots — typically 1–2mm in diameter — found in clusters or streaks along mattress seams, on bedding fabric, on wooden bed frame joints, and on nearby walls or skirting boards. These spots are digested blood and do not wash out easily. On light fabric, they typically bleed slightly when wet, similar to a felt-tip pen mark. The concentration of spots gives a strong indication of infestation severity — scattered spots may indicate a recently introduced infestation, while dense clusters suggest an established bed bug colony.

Look particularly along the piping and seams of your mattress, at the corners of the box spring if applicable, under the mattress label, and on the underside of the bed frame. In heavy infestations, staining can extend to the headboard, nearby walls, and even electrical outlet covers. These dark spots remain one of the most reliable early signs of bed bugs in any Delhi NCR home.

Bed bug excrement spots on a mattress seam — one of the most reliable early signs of infestation.

Shed Skins (Exoskeletons)

As bed bug nymphs develop through their five growth stages, they shed their outer skin (exoskeleton) each time they moult. These shed skins, or exuviae, are hollow and translucent, roughly matching the shape of a bed bug but with a papery, empty appearance. Finding shed skins — particularly in clusters in hiding spots — is strong evidence of an active, developing infestation rather than a one-off encounter with a single insect. Shed skins are most commonly found in the same locations as live bugs: mattress seams, bed frame joints, behind headboards, and in the tufts of upholstered furniture.

Live or Dead Bed Bugs

Finding a live or dead bed bug is the most definitive confirmation of a bed bug infestation. Live bugs are most active between 1 AM and 5 AM when hosts are asleep and motionless, making daytime discovery less common unless the infestation is heavy or the bugs have been disturbed. If you find a dead bed bug — on the mattress surface, on the floor near the bed, or in bedding — this strongly suggests an active infestation rather than an isolated incident, as bed bugs do not enter homes individually.

Musty, Sweet Odour

A large bed bug infestation produces a distinctive musty, sweet odour described by many as similar to coriander or overripe raspberries. This odour is produced by pheromones released by the bugs and becomes noticeable when a significant population is present in one area. If you notice an unexplained sweet or musty smell in a bedroom that was not there previously — particularly if combined with any of the other signs of bed bugs above — it warrants a thorough inspection by a professional pest control team.

Blood Stains on Sheets and Pillowcases

Small reddish-brown blood stains on bed sheets, pillowcases, or mattress fabric are a common early sign of bed bugs. These stains occur when a feeding bed bug is accidentally crushed by the sleeping person's movement, or when a small amount of blood is left at the bite site. Unlike the excrement spots (which are dry and dark), fresh blood stains are bright red and may smear. Finding these stains consistently over multiple mornings is a strong indicator of active bed bug feeding and warrants immediate professional assessment.

Where Bed Bugs Hide in Your Home

Bed bugs are cryptic insects — they avoid light and activity, preferring to stay within 1–2 metres of their host's sleeping location. Understanding their preferred hiding spots makes bed bug identification and inspection significantly more effective.

Bed bug colony found inside a wooden bed frame joint during a professional inspection — one of their most common hiding spots.

Bed Bug Bites: What to Look For

Bed bug bites typically appear as small, flat or raised red welts on the skin. They are often described as similar in appearance to mosquito bites but tend to occur in a distinctive pattern — bites are frequently found in rows or clusters of three (colloquially called "breakfast, lunch, and dinner"), reflecting the bed bug's feeding pattern of sampling multiple times along a single blood vessel. Bite sites are most commonly on exposed skin during sleep: the neck, face, arms, hands, and shoulders. Identifying this pattern of bites is one useful — though not definitive — sign of bed bugs.

A critical point that causes many infestations to go undetected initially is that bed bug bites do not always cause an immediate reaction. Approximately 30% of people show no skin reaction to bed bug bites at all, and in others — particularly those experiencing their first exposure — the reaction may be significantly delayed, appearing 1–2 weeks after the actual bite. This means you may have an active bed bug infestation for weeks before the bites become visible. Children and elderly individuals tend to show more pronounced reactions than healthy adults.

It is important to note that bed bug bites alone cannot confirm an infestation — many skin conditions, allergic reactions, and other insect bites produce identical-looking marks. Diagnosing a bed bug infestation solely on the basis of bites is unreliable and frequently incorrect. The physical evidence in the bed area (dark spots, shed skins, live bugs) is always more reliable for confirmation than bite marks on skin. Always look for multiple signs of bed bugs before drawing conclusions.

Most bed bug bites resolve without treatment in 1–2 weeks. Antihistamine cream can reduce itching and mild reactions. However, seek medical attention if: you develop a widespread rash, facial swelling, or difficulty breathing (signs of an allergic reaction); bite sites become infected from scratching; or you experience significant sleep disruption or anxiety as a result of the bed bug infestation. In Delhi NCR's humid climate, secondary skin infections from scratched bites are more common than in drier environments — keeping bite sites clean and avoiding scratching is important.

What to Do If You Find Bed Bugs

Finding evidence of bed bugs is alarming, but acting correctly in the first 24–48 hours significantly affects the outcome of treatment. Here is what to do — and what to avoid.

1. 1

   Do Not Panic — But Do Act Quickly

   Bed bugs spread slowly compared to many pests, and a recently identified infestation that has not yet spread beyond the bedroom is considerably easier (and less costly) to treat than one that has been present for months. Resist the impulse to throw out your mattress immediately — this is rarely necessary with professional bed bug treatment, and moving an infested mattress risks spreading bugs to other parts of the home.

2. 2

   Do Not Spray DIY Products Yet

   Applying over-the-counter sprays (Baygon, HIT, or similar) before professional inspection almost always makes the situation worse: it kills some surface bugs while causing the surviving population to scatter deeper into the room and into adjacent areas, significantly complicating treatment. DIY sprays do not reach bed bug harborage sites, do not kill eggs, and do not provide residual protection. Hold off until you have professional advice.

3. 3

   Contain the Infestation

   Avoid carrying bedding, pillows, or clothing from the infested room to other parts of the home before treatment. Do not move furniture out of the room. If you sleep in another room to avoid bites, you risk carrying bugs on your clothing and introducing them to a new area. Your bed — uncomfortable as it is — is currently the best place to sleep until bed bug treatment is complete.

4. 4

   Document the Evidence

   Photograph any evidence you find — spots on the mattress, shed skins, or live bugs. This helps the pest control technician confirm the bed bug infestation type and severity before treatment, and ensures the correct treatment method is selected. Use your phone's macro mode or a magnifying glass to capture clear images.

5. 5

   Wash and Dry Bedding at High Temperature

   Machine wash all bedding, pillowcases, and any clothing from the affected room at 60°C or above, then dry on the highest dryer setting for at least 30 minutes. Heat above 50°C kills bed bugs at all life stages including eggs. Place washed items in sealed bags until treatment is complete. Do not return bedding to the bed before treatment.

6. 6

   Call a Professional

   Bed bugs are one of the most difficult urban pests to eliminate without professional intervention — their flat bodies allow them to hide in locations that household products cannot reach, and their eggs are naturally resistant to many chemical treatments. Niramay Pest Control provides free on-site inspection across Delhi NCR — our technician will confirm the infestation, identify all harborage sites, and recommend the most appropriate bed bug treatment (heat, chemical, or a combination).