# Scabies

Manage suspected scabies by confirming when uncertainty changes management, treating the patient and close contacts concurrently, distinguishing crusted disease early, and reassessing persistent itch for reinfestation, application failure, dermatitis, or an alternative diagnosis.

**Clinical question:** How should physicians diagnose, treat, and prevent transmission of classic or crusted scabies?

Updated: 2026-09-15T23:46:35.694167+00:00

## What matters in practice
- Confirm scabies by identifying a mite, eggs, or feces on microscopy, dermoscopy-guided sampling, adhesive tape testing, or biopsy when diagnostic uncertainty will change therapy or infection-control actions; a negative scraping does not exclude disease because conventional microscopy is insensitive. [2][7][8][10]
- For classic scabies, select permethrin 5% topical therapy or oral ivermectin according to feasibility, patient preference, cost, and ivermectin drug-interaction considerations; ivermectin is used as 2 doses separated by 7 to 14 days. [13][18][19]
- Treat household, sexual, and other close personal contacts concurrently with the index case to reduce reinfestation; do not wait for symptoms in exposed contacts. [17][22][24]
- Suspect crusted scabies in patients with extensive hyperkeratotic disease, immunocompromise, frailty, or institutional exposure; use combined oral ivermectin and topical permethrin and institute immediate outbreak-control measures. [4][12][17][18]
- Persistent pruritus alone for 2 to 4 weeks after treatment does not establish treatment failure; new active lesions, persistent infestation on repeat testing, untreated contacts, incorrect topical use, and post-scabetic dermatitis direct the next step. [20][22][23]

## Confirm scabies when the result changes treatment or infection control

Clinical diagnosis is often sufficient when exposure and typical findings align.

Use the history of symptomatic close contacts, nocturnal pruritus, and compatible lesions to make a working diagnosis when immediate treatment is appropriate. Seek parasitologic confirmation when lesions are atypical, the differential would alter management, prior therapy has apparently failed, or a suspected case may trigger facility-wide control actions. Definitive confirmation is visualization of mites, eggs, or feces in a skin scraping or biopsy. [7][8][10][16]

Dermoscopy can direct sampling to a suspected burrow; microscopy of the resulting scraping can confirm infestation but is insensitive, invasive, and often impractical. Conventional skin-scraping microscopy has been reported to have sensitivity below 50%, so a negative result should not overrule a compelling clinical and epidemiologic presentation. [2][10]

Do not use investigational immunodiagnostic assays to rule in or rule out routine human scabies. PCR, real-time PCR, ELISA, and immunohistochemistry have been investigated, but the cited lateral-flow assay was only a small animal-sample prototype. [2]
- Escalate diagnostic certainty before repeated empiric scabicides when dermatitis from the mite or topical agent, incorrect initial diagnosis, reinfestation, or inadequate application is plausible. [20][23]
- Examine close contacts when they have suggestive findings; contact findings can strengthen a clinically uncertain diagnosis. [14]
- Assess for bacterial superinfection when excoriated lesions suggest secondary infection, a recognized complication of scabies. [16]

*Diagnostic approach for suspected scabies. [2][7][8][10][16]*

| Clinical situation | Best next action | How the result changes management |
| --- | --- | --- |
| Typical clinical syndrome with symptomatic close contacts | Treat clinically and organize concurrent contact treatment. [16][22] | Avoids delay that permits ongoing transmission. [22] |
| Atypical eruption or meaningful competing diagnosis | Perform dermoscopy-directed scraping, adhesive tape test, or biopsy for mite, egg, or feces identification. [7][8][10] | Positive visualization confirms scabies; negative microscopy does not exclude it. [2][10] |
| Persistent symptoms after treatment | Reassess application, contact treatment, environmental control, active lesions, and repeat scraping after topical scabicide washout when eradication is uncertain. [20][23] | Distinguishes post-scabetic itch or dermatitis from persistent infestation or reinfestation. [20][23] |
| Possible crusted scabies in a congregate setting | Treat as highly transmissible while arranging aggressive combined therapy and local or state health department involvement. [17][18] | Limits outbreak propagation from high mite burden and fomite transmission. [17] |

## Choose permethrin or ivermectin and eliminate the reinfestation cycle

Treatment selection is driven chiefly by topical feasibility, host factors, and exposure management.

For classic scabies, CDC lists prescription topical permethrin and oral ivermectin among first-line options. Choose between topical and oral therapy using patient preference, capacity to perform whole-body topical treatment, cost, and potential ivermectin interactions, including those listed with azithromycin, trimethoprim-sulfamethoxazole, and cetirizine. No nonprescription product has been tested and approved for treatment of human scabies. [18][19]

Permethrin 5% cream is the preferred initial agent when its safety profile is decisive, including in children older than 2 months and during pregnancy. Apply treatment carefully to all involved skin; inadequate topical application is a common cause of apparent failure. Consider application above the neck in children or older adults with significant scalp involvement. [20][24]

Oral ivermectin is useful when topical therapy is impractical, for institutional outbreak operations, and for crusted disease; it is not FDA-approved for scabies. When used for classic scabies, administer 2 doses 7 to 14 days apart. Ivermectin lacks safety data in children weighing less than 15 kg and in pregnancy; one cited guidance also does not recommend it during lactation. [13][16][24]

Treat close contacts at the same time as the index patient, including household members, sexual contacts, and other close personal contacts. Concurrent treatment addresses asymptomatic incubation and is the principal operational step to prevent immediate reinfestation after otherwise effective therapy. [17][22][24]
- Use oral therapy preferentially when a patient cannot reliably complete topical application or when coordinated mass treatment is necessary in an outbreak. [6][18][24]
- Avoid assuming that itching immediately after therapy represents viable mites: pruritus can persist for 1 to 2 weeks and may last 2 to 4 weeks after successful treatment. [20][22]
- Support persistent itch or post-scabetic dermatitis with emollients and antihistamines when clinically appropriate while reassessing for active lesions and exposure-related reinfestation. [20]

*Treatment selection for classic scabies. [13][16][18][19][20][24]*

| Option | When to favor it | Key constraints |
| --- | --- | --- |
| Permethrin 5% cream | Initial therapy when topical treatment can be completed; safety profile supports use in children older than 2 months and pregnancy. [24] | Failure commonly reflects incomplete application; consider above-neck application in children or older adults with scalp involvement. [20] |
| Oral ivermectin | Topical treatment impractical, institutional outbreak logistics, or crusted disease. [18][24] | For classic scabies, use 2 doses 7 to 14 days apart; off-label for scabies and not recommended in children under 15 kg or pregnancy in cited guidance. [13][16][24] |
| Alternative prescription scabicides | Use when first-line therapy is unsuitable or unavailable after considering availability, efficacy, cost, adverse effects, and patient preference. [18][19] | Direct comparative evidence for alternatives is limited. [18][19] |

## Recognize crusted scabies and treat it as an infection-control emergency

Crusted disease changes both treatment intensity and the scope of contact tracing.

Suspect crusted scabies in patients with extensive hyperkeratotic or crusted lesions, especially those who are immunocompromised, older, frail, or debilitated. Ordinary scabies generally carries a low mite burden, whereas crusted disease can contain up to millions of mites and is correspondingly much more transmissible. [4][17]

Unlike classic scabies, crusted scabies can spread through brief direct contact and through contaminated clothing, bedding, and furniture. In hospitals, assisted-living facilities, correctional settings, and other group facilities, act immediately: identify close contacts, begin treatment promptly, and contact the local or state health department for outbreak control. [17]

Treat crusted scabies with both prescription oral and topical agents; CDC identifies oral ivermectin plus topical permethrin as first-line combination therapy. The duration and intensity of treatment depend on disease severity, and pediatric guidance notes that multiple doses of both topical and oral therapy are typically required. [12][17][18]
- Do not manage suspected crusted scabies with a classic-scabies single-modality strategy. Combined oral and topical treatment is required. [17][18]
- Trace and treat household, sexual, and close personal contacts as soon as the diagnosis is made. [17]
- A delayed diagnosis, atypical presentation after inappropriate topical corticosteroid treatment, and inability to report symptoms are recognized drivers of institutional spread. [4]

*Classic versus crusted scabies: management-changing distinctions. [4][12][17][18]*

| Feature | Classic scabies | Crusted scabies |
| --- | --- | --- |
| Mite burden and transmission | Usually a small mite burden; transmission is primarily through direct skin-to-skin contact. [4][24] | Very high mite burden; brief direct contact and contaminated clothing, bedding, or furniture can transmit infestation. [4][17] |
| Therapeutic approach | Permethrin 5% or oral ivermectin may be selected based on patient and treatment factors. [18][19] | Use combined oral ivermectin and topical permethrin; multiple oral and topical doses are typically required. [12][17][18] |
| Public-health action | Treat close contacts concurrently to prevent reinfestation. [22][24] | Immediately identify and treat contacts; involve public health for group-facility outbreak control. [17] |

## Coordinate contacts and environmental measures rather than repeatedly retreating one patient

Most apparent recurrence is operational: untreated exposure networks or incomplete topical delivery.

When treating an individual case, synchronize therapy for the patient and close contacts rather than sequencing treatment after symptoms develop. Failure to treat contacts simultaneously, incomplete bedding and clothing decontamination, and nonadherence are common causes of recurrence or apparent treatment failure. [22][24]

For a facility cluster or a crusted index case, identify affected residents, patients, staff, and close personal contacts; combine patient and staff information efforts with coordinated treatment of affected individuals and contacts. Published outbreak strategies have used ivermectin, permethrin 5%, or benzyl benzoate to halt outbreaks, but local and state public-health guidance should direct the operational response. [6][17]

Prioritize environmental measures in crusted scabies because contaminated clothing, bedding, and furniture can contribute to spread. In classic scabies, direct contact is the principal route, so environmental efforts should support—not replace—simultaneous treatment and contact management. [17][24]
- Review every topical-treatment failure by asking who applied the medication, whether all indicated skin was covered, whether close contacts were treated simultaneously, and whether the patient had renewed exposure. [20][23][24]
- Treat a suspected crusted case aggressively before a facility outbreak is fully characterized because outbreaks are more common with crusted disease. [17]
- Avoid attributing spread to poor hygiene alone; crowding and clustered living conditions are important outbreak contexts. [20][23]

*Operational response by transmission setting. [6][17][22][24]*

| Setting | Immediate action | Escalation trigger |
| --- | --- | --- |
| Household or sexual network | Treat the index patient and close contacts concurrently. [17][22] | Recurrent active lesions after coordinated therapy should prompt reassessment for missed contacts, application failure, or diagnostic error. [20][23] |
| Hospital, long-term care, correctional, or other group facility | Identify contacts, coordinate prompt treatment, and use staff and patient information measures. [6][17] | Crusted scabies or ongoing spread warrants local or state health department involvement. [17] |
| Crusted index case | Use combined oral and topical treatment and address contaminated clothing, bedding, and furniture. [17][18] | Any exposure network in a group facility requires immediate outbreak-control actions. [17] |

## Differentiate post-scabetic itch from persistent infestation

Follow-up should focus on active lesions and exposure control, not itch alone.

Assess treatment response at approximately 2 weeks, while recognizing that pruritus can persist for up to 1 month after successful eradication. Resolution of active lesions with residual itch favors post-scabetic dermatitis or recovery rather than viable infestation; emollients and antihistamines may be used for symptom control. [20][23]

If new lesions continue to appear, exposure persists, or symptoms remain clinically concerning, first audit the regimen: incomplete topical coverage, poor penetration into hyperkeratotic skin or nails, untreated close contacts, inadequate environmental control, reinfestation, and incorrect diagnosis are more common explanations than confirmed drug resistance. [20][23][24]

When the distinction remains consequential, repeat skin scrapings after washout of topical scabicides to seek persistent mites, eggs, or feces. Confirmed persistence after a correctly applied, coordinated regimen should prompt selection of an alternative therapy and reconsideration of resistance, although the clinical importance of reported permethrin and ivermectin resistance remains debated. [20][21][23]
- Do not label persistent itching alone as treatment failure during the first 2 to 4 weeks after therapy. [20][22]
- Use repeat microscopy to support escalation when persistent infestation—not dermatitis or reinfestation—is the management question. [20]
- In crusted scabies, inspect hyperkeratotic skin and nails for poor topical penetration before declaring drug failure. [23]

*Approach to symptoms after scabies treatment. [20][21][22][23][24]*

| Follow-up finding | Most useful interpretation | Next step |
| --- | --- | --- |
| Itch persists but active lesions are resolving within 2 to 4 weeks | Post-scabetic itch or dermatitis is likely. [20][22][23] | Provide symptomatic care and avoid automatic retreatment. [20] |
| New lesions or ongoing exposure after treatment | Reinfestation, missed contacts, incorrect topical use, or inadequate environmental control is likely. [20][23][24] | Treat missed contacts concurrently and correct application and environmental failures. [22][24] |
| Persistent lesions after correctly coordinated treatment | Confirm persistent infestation and reconsider diagnosis or reduced drug response. [20][21][23] | Repeat scraping after topical washout; if infestation is confirmed, use an alternative therapy and reassess transmission control. [20][21] |
| Hyperkeratotic crusted disease does not improve | Poor topical penetration and high mite burden can sustain infestation. [12][23] | Ensure combined oral and topical treatment intensity appropriate to severity and reinforce infection control. [12][17][18] |

## References
1. Oral ivermectin versus 5% permethrin cream to treat children and adults with classic scabies: multicentre, assessor blinded, cluster randomised clinical trial — www.bmj.com — https://www.bmj.com/content/392/bmj-2025-086277
2. Development of a rapid scabies immunodiagnostic assay based on transcriptomic analysis of Sarcoptes scabiei var. nyctereutis | Scientific Reports — www.nature.com — https://www.nature.com/articles/s41598-021-85290-7
3. Ectoparasites: Scabies - ScienceDirect — www.sciencedirect.com — https://www.sciencedirect.com/science/article/abs/pii/S0190962219323850
4. Management of a family outbreak of scabies with high risk of spread to other community and hospital facilities - ScienceDirect — www.sciencedirect.com — https://www.sciencedirect.com/science/article/abs/pii/S0196655317313056
5. Crusted scabies at a tertiary care center: Case series and cautionary ... — www.sciencedirect.com — https://www.sciencedirect.com/science/article/pii/S2352512623003235
6. Control of scabies outbreaks in an Italian hospital: An information-centered management strategy - ScienceDirect — www.sciencedirect.com — https://www.sciencedirect.com/science/article/abs/pii/S0196655313013199
7. Dermoscopy of Pediatric Infectious and Inflammatory Skin Lesions ... — onlinelibrary.wiley.com — https://onlinelibrary.wiley.com/doi/10.1111/pde.12097
8. Detection of Scabies: A Systematic Review of Diagnostic Methods — onlinelibrary.wiley.com — https://onlinelibrary.wiley.com/doi/pdf/10.1155/2011/698494
9. Scabies polymerase chain reaction with standardized dry swab ... — onlinelibrary.wiley.com — https://onlinelibrary.wiley.com/doi/abs/10.1111/bjd.18017
10. The 2020 International Alliance for the Control of Scabies ... — onlinelibrary.wiley.com — https://onlinelibrary.wiley.com/doi/10.1111/bjd.18943
11. Review of Scabies Infestation and Selected Common ... — publications.aap.org — https://publications.aap.org/pediatricsinreview/article/42/1/21/35454/Review-of-Scabies-Infestation-and-Selected-Common
12. Scabies | Red Book Atlas of Pediatric Infectious Diseases — publications.aap.org — https://publications.aap.org/aapbooks/monograph/797/chapter/16871038/Scabies
13. Scabies | Red Book Atlas of Pediatric Infectious Diseases | AAP Books — publications.aap.org — https://publications.aap.org/aapbooks/book/723/chapter/10679245/Scabies
14. Insect Bites and Infestations (Chapter 277) — publications.aap.org — https://publications.aap.org/pediatriccare/book/348/chapter/5782048/Insect-Bites-and-Infestations-Chapter-277
15. Ivermectin and permethrin for treating scabies - Rosumeck, S — www.cochranelibrary.com — https://www.cochranelibrary.com/cdsr/doi/10.1002/14651858.CD012994/references
16. Evidence and recommendations on scabies - NCBI - NIH — www.ncbi.nlm.nih.gov — https://www.ncbi.nlm.nih.gov/books/NBK305419
17. Clinical Overview of Crusted Scabies - CDC — www.cdc.gov — https://www.cdc.gov/scabies/hcp/clinical-overview/index.html
18. Clinical Care of Scabies | Parasites - Scabies | CDC — www.cdc.gov — https://www.cdc.gov/scabies/hcp/clinical-care/index.html#print
19. Clinical Care of Scabies | Parasites - CDC — www.cdc.gov — https://www.cdc.gov/scabies/hcp/clinical-care/index.html
20. Infected with Scabies Again? Focus in Management in Long-Term Care Facilities - PMC — pmc.ncbi.nlm.nih.gov — https://pmc.ncbi.nlm.nih.gov/articles/PMC6473425
21. Escalating Threat of Drug-Resistant Human Scabies: Current Insights and Future Directions — pmc.ncbi.nlm.nih.gov — https://pmc.ncbi.nlm.nih.gov/articles/PMC11432065
22. Interventions for treating scabies - PMC — pmc.ncbi.nlm.nih.gov — https://pmc.ncbi.nlm.nih.gov/articles/PMC6532717
23. The Management of Scabies in the 21st Century: Past, Advances and Potentials — pmc.ncbi.nlm.nih.gov — https://pmc.ncbi.nlm.nih.gov/articles/PMC9128908
24. Scabies - StatPearls - NCBI Bookshelf — www.ncbi.nlm.nih.gov — https://www.ncbi.nlm.nih.gov/books/NBK544306

## Editorial note

Prepared from cited clinical literature using Astra's research workflow. Verify recommendations against current guidance and patient-specific factors.