Scabies is contagious from roughly one to two weeks after transmission, so well before you notice anything yourself, until about twelve hours after you start treatment. Those twelve hours come from the RIVM LCI guideline, provided you follow the hygiene measures.
The itch afterwards is not a yardstick.
Many people keep itching for weeks when there is no live mite left on their skin. That is an after-effect of the allergic reaction, not a sign that you are still contagious.
From when are you contagious?
You are contagious once adult mites are walking on your skin and able to cross over, usually one to two weeks after transmission. The itch starts much later, after two to six weeks with a first infestation. That gap between being contagious and having symptoms is what makes scabies awkward.
You pass it on before you know.
With a second infestation the order reverses. Your immune system already knows the mite, so the itch can appear within one to four days (RIVM).
How long are you contagious after treatment?
About twelve hours after the first treatment you are in practice no longer contagious, provided you applied the cream correctly and use clean clothing and bedding. That does not mean you are finished: the second round after a week still belongs to the course.
| Moment | Contagious? | What is happening |
|---|---|---|
| Week 0, the contact | No | Mites arrive on the skin, too few and too young |
| Week 1 to 2 | Yes | Mites are adult and can walk across |
| Week 2 to 6 | Yes | Itch begins, often only now is it noticed |
| First 12 hours of treatment | Yes | Mites are dying, but not all of them yet |
| From 12 hours after starting | No | Provided correct application and clean textiles |
| Week after treatment | No | Itch may persist, an allergic after-effect |
The second-to-last row is the row people come looking for. The last row is the one that reassures them.
Why does the itch continue after treatment?
The itch comes from an allergic reaction to the mite and its droppings, and that material is still in your skin once the mites are dead. Your immune system needs time to settle. Two to four weeks of after-effect is not unusual.
Unpleasant, but not a failure.
New burrows or new bumps appearing after treatment are a reason to go back to your GP. The difference lies in new skin lesions, not in the sensation.
When can you have sex again?
After twelve hours the transmission risk is small, but there is little point resuming before your partner has been treated too. Otherwise you simply hand the mite back. The guideline therefore advises treating partners and household members at the same time.
Simultaneous matters more than fast.
Why scabies sits in the STI guideline without being a classic STI is explained in is scabies an STI.
How long does the mite survive off the body?
Away from human skin the scabies mite survives roughly two to three days, depending on temperature and humidity. That is why washing recent clothing and bedding at 60 degrees is enough, and why anything unwashable can simply be set aside for a few days.
You do not need to throw out your mattress.
The rare crusted form is different, because it carries up to 4,700 mites per gram of skin flake and textiles do play a major role (RIVM). That form mainly occurs in people with reduced immunity.
And what does this mean for testing?
For scabies itself it means nothing, because no lab test exists. The diagnosis is made by looking. What does matter is that prolonged skin contact often coincides with sexual contact, and that brings infections which are measurable.
The RIVM guideline says as much: consider STI testing if the infestation was probably acquired through sexual contact.
Chlamydia and gonorrhoea can generally be shown reliably from around two weeks after the risk, for example with a combined test for chlamydia, gonorrhoea and trichomonas. How this connects to parasitic skin complaints is covered in our main article on pubic lice. Discuss any result with your GP.
References
- RIVM, LCI guideline scabies. lci.rivm.nl
- Rosumeck S, Nast A, Dressler C. Ivermectin and permethrin for treating scabies. Cochrane Database of Systematic Reviews, 2018. PMID 29608022
- Patel PU, Tan A, Levell NJ. A clinical review and history of pubic lice. Clinical and Experimental Dermatology, 2021. PMID 33811771
- Richtlijnendatabase, Multidisciplinary guideline on sexually transmitted infections, scabies module. richtlijnendatabase.nl
Every blood test result includes a professional assessment from a BIG-registered doctor. For treatment decisions, discuss your results with your GP.
الكاتب
Discreettest
Dr. Naimi، طبيب مسجل في سجل BIG الهولندي، يشرف على المعايير الطبية لمحتوانا وتقييماتنا. اقرأ سياستنا الطبية
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