Bites That Are Not Bed Bugs

Waking with marks and finding nothing on the mattress is a common and unsettling situation, and the internet takes everybody to the same conclusion.

In Ho Chi Minh City the realistic alternatives are numerous, and several of them are considerably more likely than bed bugs. Working through them saves both money and a great deal of anxiety.

Mosquitoes, by a wide margin

The most common answer. Bites appear on exposed skin, often on ankles and arms, tend to be individual rather than grouped, and appear within minutes rather than hours.

The reason people miss this is that Aedes bites during the day and rests indoors, so a bite acquired at four in the afternoon can be attributed to the previous night. A single mosquito in a bedroom overnight can also produce several bites that look convincingly like a pattern.

Fleas

Concentrated below the knee, particularly around the ankles, because fleas jump from floor level. Small, intensely itchy, often with a tiny darker centre.

A household with a pet is the obvious case, and a household without one is not excluded — a previous tenant\x27s pet leaves pupae that survive months and hatch when somebody walks in.

A wooden bed frame and mattress edge seen from a tiled floor.

Mites

Bird mites are a genuinely common cause here and are consistently overlooked. Pigeons nesting on an air-conditioner unit, a ledge or a balcony produce mites that enter the building when the birds leave or when chicks fledge, and they bite people because their normal host has gone.

The diagnostic clue is a bird nest within a few metres of the affected room. Removing the nest and treating the area resolves it, and no amount of treatment inside the room will work while the nest remains.

Paederus dermatitis, which is not a bite at all

The kiến ba khoang rove beetle produces a distinctive linear red rash with blistering, often appearing overnight, and it is caused by a chemical in the insect\x27s body released when it is crushed against skin rather than by any bite.

The linear streak, sometimes with a matching mark where a limb touched another part of the body, is characteristic and quite different from any true bite. It is seasonal here and associated with lights at night.

Things that are not insects

Contact dermatitis from a new detergent, fabric softener or bedding. Heat rash, which is extremely common in this climate and appears on covered skin. Urticaria from food, medication or stress. Scabies, which is a mite living in the skin rather than visiting it, and which produces intense itching that is markedly worse at night with burrow lines between the fingers.

Scabies in particular is worth mentioning because it is treated medically rather than by a pest controller, and because it is frequently mistaken for bed bugs for weeks.

A technician carrying a sprayer into a bedroom cleared of mattresses.

What separates them

Location on the body: below the knee suggests fleas, exposed skin suggests mosquitoes, covered skin suggests something in the bedding or a rash. Timing: appearing within minutes suggests mosquitoes, appearing hours later or on waking is consistent with bed bugs. Whether anyone else in the household is affected, and whether it stops when you sleep elsewhere.

That last test is the most useful single piece of information. Sleeping in a different property for several nights and having the marks stop points at the bedroom; having them continue points away from it.

What to do before booking anything

Photograph the marks with a date, note where on the body and what time they appeared, and do the ten-minute torch search of the headboard, mattress seams, frame joint and drawer runner. Then look outside the window for a bird nest.

That costs nothing and answers the question in most cases. If it does not, interceptor cups under the bed legs for a fortnight give a dated result that a single inspection cannot.

Common questions

Only one person in the house is affected. Does that rule out bed bugs?

No, and it is one of the more misleading signals. Reaction to bed bug bites varies enormously and a substantial proportion of people show no visible reaction at all, so one affected person in a shared bed is entirely consistent with an infestation. It is equally consistent with a skin condition, which is why the physical evidence search matters more than the pattern of who is affected.

Can you tell from a photograph of the bites?

Not reliably, and anyone who says otherwise is overstating. Bite reactions look broadly similar across several causes and vary between individuals. A photograph of the mattress seam, the headboard or the insect is far more useful than a photograph of your arm, which is why we ask for those instead.

We found a bird nest on the air-conditioner. Is that it?

Very possibly, and it is one of the more satisfying diagnoses because it explains bites that no bedroom inspection could account for. The nest needs removing and the area treating, and it is worth doing promptly since mites become most active in seeking a new host once the birds leave.