Is It Scabies?
Night itch and an itching household outweigh what the rash looks like — plus burrows, eczema, hives, bites, and the itch that is telling you something else.
Part of the Complete Scabies Guide.
Key fact: Two features together make scabies far more likely than anything else: itching that is dramatically worse at night, and someone else in the household itching too. Neither is proof, but together they outweigh what the rash looks like.
The scabies signature
- Itch dramatically worse at night, often waking the person — the mites are more active when the skin is warm
- Someone else in the household is itching, frequently starting at a different time
- The distribution: finger webs, wrists, elbows, armpits, waist, buttocks, groin, nipples — and sparing the head and neck in adults
- A rash out of proportion to the cause — widespread spots from a dozen mites, because it is an allergic reaction
- It does not settle with emollients or a mild steroid cream, which is often what has been tried first
- Weeks of build-up rather than a sudden onset
Burrows
The one finding that is genuinely specific to scabies. A burrow is a fine, slightly raised, greyish or silvery wavy line, usually 2 to 10mm long, sometimes with a tiny dark speck at one end.
- Look in the finger webs first, then the sides of the fingers and the inner wrists
- Good light and, if possible, a magnifier — they are small and easily missed
- Scratching destroys them, which is why they are often absent by the time anyone looks
- In men, a burrow or itchy lump on the penis or scrotum is highly suggestive
- Not finding one does not exclude scabies, and finding one settles it
Eczema and dermatitis
The commonest misdiagnosis in both directions, and the two frequently coexist because scratching scabies produces eczematous skin.
| Points to eczema | Points to scabies |
|---|---|
| A long history, often since childhood | New, developing over weeks |
| Flexures — inner elbows, behind the knees | Finger webs, wrists, waist, genitals |
| Itchy at any time, worse when hot | Dramatically worse at night |
| Nobody else affected | Household members itching too |
| Improves with emollients and steroid cream | Does not improve, or worsens, with steroid alone |
Scabies treated as eczema with a steroid cream gets worse in a particular way. The steroid damps the allergic reaction, so the itch eases briefly and the rash becomes less typical while the mites multiply unchecked. A rash that improves slightly on steroid then spreads is a reason to reconsider, not to increase the steroid.
Hives and drug reactions
- Urticaria — raised weals that come and go within hours, each individual weal lasting less than a day, moving around the body. Scabies spots stay put
- A drug rash — usually symmetrical, widespread, starting days after a new medicine, and involving the trunk more than the finger webs
- Neither spares the head and neck in the way scabies does, and neither spreads to other people
Insect and flea bites
- Flea bites — clustered around the ankles and lower legs, often with a central punctum, and there is usually a pet
- Bed bugs — bites in rows or clusters on exposed skin, appearing overnight, worse after nights in a particular bed
- Both are discrete lesions rather than the diffuse, spotty, burrow-containing eruption of scabies
- Neither favours the finger webs and genitals
The other causes of a whole-body itch
- Dry skin — particularly in older adults and in winter, with scaly rather than spotty skin
- Dermatitis herpetiformis — intensely itchy blisters on elbows, knees and buttocks, linked to coeliac disease
- Liver, kidney or thyroid disease, or iron deficiency — generalised itch with no rash of its own
- Lymphoma and some blood disorders — a rare but recognised cause of persistent unexplained itch
- Medication — opioids in particular
- Pregnancy — itch in later pregnancy, especially of the palms and soles without a rash, needs assessment in its own right
Itching with no rash at all
Scabies almost always produces something visible, even if only scratch marks. A truly generalised itch with entirely normal skin points elsewhere — commonly dry skin, and sometimes an underlying medical cause worth a blood test.
Persistent unexplained itch with no rash, particularly with weight loss, night sweats or swollen glands, should be assessed rather than treated as scabies.
When it has become infected
Scratching breaks the skin, and broken skin gets infected. Golden-crusted sores appearing among the scratch marks are impetigo, and they need their own treatment alongside the scabies.
Get assessed if the skin is weeping, crusted or has golden crusts; there is spreading redness, heat and swelling; there is fever or the person feels unwell. Treating the mites alone leaves the bacterial infection running, and impetigo treatments covers what that needs.
How it is confirmed
- Usually on the history and the pattern — night itch, distribution, and affected contacts
- Finding a burrow confirms it
- Dermoscopy — a magnified look, which can show the mite at the end of a burrow
- Skin scrapings examined under a microscope, used less often in general practice
- A trial of treatment is reasonable where the picture fits, given how specific the night-itch-plus-contacts combination is
Once you are reasonably confident, the thing that decides the outcome is how the treatment is applied — see scabies treatment, step by step.
A widespread raised rash or spots, often with scratch marks, affecting the finger webs, wrists, elbows, armpits, waist, buttocks, groin and around the nipples, and usually sparing the head and neck in adults. The specific finding is a burrow: a fine, slightly raised, greyish wavy line a few millimetres long, most often in the finger webs. The mites become more active when the skin is warm, and there are fewer distractions at night. Itching that is dramatically worse at night, particularly if it wakes you, is the most characteristic feature of scabies and is one of the two things that most strongly separate it from eczema. Very often, in both directions, and the two frequently coexist because scratching produces eczematous skin. Eczema tends to have a long history and affect the inner elbows and behind the knees; scabies is new, favours the finger webs, wrists, waist and genitals, is much worse at night, and affects other people in the household. Almost always something is visible, even if only scratch marks. A truly generalised itch with entirely normal skin usually points elsewhere, commonly to dry skin, and sometimes to an underlying medical cause such as liver, kidney or thyroid disease, or iron deficiency. Golden-crusted sores appearing among scratch marks are usually impetigo, a bacterial infection of skin broken by scratching. It needs its own treatment alongside the scabies, because treating the mites alone leaves the bacterial infection running.Frequently Asked Questions
What does scabies look like?
Why is scabies itching worse at night?
Can scabies be mistaken for eczema?
Does scabies always cause a rash?
What are the crusty sores among my scabies rash?
References
- NHS. Scabies. nhs.uk
- National Institute for Health and Care Excellence. Clinical Knowledge Summary: Scabies. cks.nice.org.uk
- Nottinghamshire Area Prescribing Committee. Scabies: guidance for primary care. nottsapc.nhs.uk
- IUSTI. European guideline for the management of scabies. iusti.org
- UK Health Security Agency. Health protection in children and young people settings, including education. gov.uk
Medical disclaimer: This article is for informational purposes only and does not constitute medical advice. Scabies treatment must be applied to the whole body and repeated after 7 days, and everyone in the household needs treating at the same time. Always read the leaflet supplied with your own product. Always consult a qualified healthcare professional for diagnosis and treatment. In a medical emergency, call 999.