Clinical Guides
Scabies
An India-contextualised, source-traceable guide to recognising, treating and containing scabies safely across households, institutions and vulnerable groups.
MedNext Academy | 13 min read
Scabies
An India-contextualised, source-traceable guide to recognising, treating and containing scabies safely across households, institutions and vulnerable groups.
Summary
Scabies is an infestation by Sarcoptes scabiei var hominis. Suspect it when intense nocturnal itch affects several household members or follows close skin contact, with burrows or papules in typical sites. The diagnosis is usually clinical; dermoscopy or microscopy can support uncertainty but a negative scraping does not safely exclude it. Treat the person and relevant household or sexual contacts together, repeat treatment when the chosen product requires it, and address clothing and bedding that had close skin contact. Explain that itch may persist for one to two weeks after successful treatment. This is not a failure signal by itself. Crusted scabies is a different level of risk: thick scale or crust, extensive disease, frailty or immunosuppression may coexist with little itch and a very high mite burden. It needs urgent clinician-led combined topical and oral treatment and infection-control planning. Secondary impetigo, cellulitis and systemic illness need separate assessment. In India, product concentration, licensing, affordability and access vary; use the current Indian label, clinician or pharmacist advice and a feasible household plan. Never use kerosene, agricultural insecticide, fumigants or unlabelled mixtures.
How Common Is It?
WHO estimates that hundreds of millions of people have scabies at any time, with the greatest burden in tropical, crowded and resource-constrained settings. A local clinic count is not a national prevalence estimate, and the apparent number of cases changes with season, household crowding, access to care and whether contacts are examined. Children, older adults, people in institutions and people living with immunosuppression may be disproportionately affected. Transmission is mainly prolonged skin-to-skin contact; ordinary brief contact and shared objects are less important in classic scabies, but fomites matter more when infestation is crusted. Symptoms can be delayed for weeks after a first infestation, so an apparently well contact may still be infected and able to transmit later. Recurrent disease may represent untreated contacts, incorrect application, reinfestation or a second diagnosis rather than resistance. Clustered cases in hostels, care homes, prisons, shelters or households require coordinated advice and sometimes public-health support. India has wide variation in housing, water, laundry facilities and medicine availability, so a control plan must be practical rather than built around expensive room decontamination.
Risk Factors
Risk rises with prolonged close contact, shared sleeping arrangements, crowded housing, institutional residence and a household member with untreated scabies. Crusted disease is particularly contagious and is associated with older age, immune suppression, neurologic disease, frailty and delayed recognition; itch may be modest despite thousands of mites. Ask about pregnancy, breastfeeding, age and weight before considering oral ivermectin, and ask about eczema or excoriated skin because an inflamed barrier can complicate examination and topical application. Previous treatment is important: record the product concentration, body areas covered, duration, whether hands were re-treated after washing, and whether close contacts were treated at the same time. Repeated over-the-counter creams, steroid combinations and home chemicals can produce irritant dermatitis and obscure the picture. Sexual partners may need contact assessment without assuming that scabies proves a sexually transmitted infection. Poverty, disability, limited water, shift work and inability to wash bedding can make adherence difficult; these are service barriers, not evidence of neglect. Consider bacterial skin infection when scratching has produced crusts, pustules, warmth, pain or fever.
Diagnosis
History
Ask when itch began, whether it is worse at night, who else itches, where the patient sleeps, and whether there has been close or sexual contact with a person with a rash. Ask about first infestation versus recurrence, previous products, pregnancy, age, weight, immunosuppression and fever.
Examination
Inspect finger webs, wrists, elbows, axillae, waist, buttocks, genitalia and breasts, while respecting privacy. Look for burrows, papules, nodules, excoriations and secondary infection. In infants and older or immunosuppressed patients examine palms, soles, scalp and the whole skin surface. Thick widespread crust suggests crusted scabies.
Investigations
Diagnosis is generally clinical. Dermoscopy may show a mite or burrow, and skin scraping microscopy can support a doubtful case, but a negative sample does not exclude scabies. Swab suspected bacterial infection when clinically indicated. Do not delay treatment of a convincing case while awaiting a test, and reassess if the pattern, contacts or response do not fit.
Differential Diagnosis
Atopic dermatitis, irritant or allergic contact dermatitis, papular urticaria, insect bites, bedbug exposure, impetigo, folliculitis, tinea, pediculosis, drug eruption and dermatitis herpetiformis can mimic scabies. In infants, consider eczema, candidiasis and bacterial infection; in older adults, xerosis and drug reactions can cause widespread itch. Burrows and nocturnal household spread support scabies, but excoriation can erase burrows and genital nodules may persist after mites are cleared. A person with itch but no live mites or typical lesions needs a deliberate diagnostic pause before repeated insecticide. Consider systemic causes of itch when the examination is atypical or treatment fails: cholestatic disease, renal disease, thyroid disease, haematological disease and iron deficiency are examples. Crusted plaques with little itch may be mistaken for psoriasis or eczema; ask about immunosuppression and examine contacts. Persistent itch for several weeks, new burrows, or new symptomatic contacts suggests reinfestation or inadequate treatment, while itch alone soon after treatment can be post-scabetic hypersensitivity. Secondary infection may coexist and should not be attributed to the mite without examining for cellulitis or systemic illness.
Management
Confirm the working diagnosis, explain transmission without blame and plan treatment for the patient and relevant household or close contacts at the same time. Follow the exact local product label. Permethrin 5% is a commonly used first-line topical option; apply to every prescribed body area, leave for the labelled period and repeat at the labelled interval because eggs may survive. Children may need head and neck coverage according to age-specific guidance; avoid eyes and mouth. Oral ivermectin can be considered by a clinician for suitable adults or for outbreaks, but safety is not established in pregnancy or children under 15 kg. Crusted scabies requires urgent specialist-led combination therapy with frequent topical treatment, oral ivermectin schedules selected for severity and removal of crust to improve penetration; isolate or use contact precautions as locally advised. Treat bacterial superinfection only when signs support it. Wash or hot-dry recently used clothing, towels and bedding; bag items that cannot be washed for the recommended period. Ordinary deep fumigation is unnecessary and dangerous. Recheck if new burrows appear, contacts remain symptomatic or infection develops. Residual itch can be managed with emollient and clinician-selected antipruritic therapy after active scabies is addressed.
Prescribing Information
This is educational information, not an individual prescription. Permethrin 5% is applied to the body according to the current local label; the exact age, application area and repeat interval must be checked in the Indian product insert. Oral ivermectin is weight-based and clinician-directed. WHO describes 200 micrograms/kg for community-control programmes, while individual schedules vary; do not convert a public-health protocol into self-medication. Avoid oral ivermectin in pregnancy and in children under 15 kg unless a specialist and current evidence justify a locally authorised alternative. Sulfur ointment may be considered where other options are unavailable, but its concentration, smell, irritation and application schedule require counselling. Benzyl benzoate and malathion have product-specific dilution and safety issues. Do not use lindane as a routine first choice; neurotoxicity and misuse are serious concerns. Avoid steroid-antimicrobial combinations as a substitute for scabicide. Review medicines and comorbidity before ivermectin because interactions and liver disease may matter. Give written instructions about clean skin, body coverage, hand reapplication after washing, nail care, repeat date, eye protection and storage. If a product burns, causes blistering or is swallowed, stop and seek urgent poison or medical advice. Never recommend kerosene, petrol, agricultural pesticide, fumigant or an unlabelled veterinary product.
When to Refer
Refer for diagnostic uncertainty, an infant or very young child, pregnancy or breastfeeding, extensive eczema, immunosuppression, frailty, neurologic disease, treatment failure after correctly performed courses, or suspected crusted scabies. Arrange urgent review for fever, rapidly spreading redness, severe pain, pus, facial swelling, dehydration or an unwell child because bacterial infection may require different care. Crusted scabies should be escalated promptly to dermatology, medicine or an infection-control-capable service; assess close contacts and the care environment. A patient who cannot apply treatment safely because of disability, cognitive impairment, homelessness or limited support needs practical assistance, not repeated prescriptions. Consider sexual-health advice when genital lesions or close sexual contacts create uncertainty, while protecting confidentiality. In India, refer or coordinate with the nearest government dermatology, primary-health or district service when a regulated product is unavailable or the household cannot complete the plan. Review persistent itch rather than automatically escalating medicines: dermatitis, tinea, drug eruption, reinfestation and incorrect application are common explanations. Provide a written date for reassessment and explain that post-treatment itch may last one to two weeks. Avoid school or work exclusion beyond local policy; focus on treatment, privacy and contact support.
Red Flags
Thick crusted or hyperkeratotic plaques, widespread scaling, little itch despite extensive disease, nail involvement, a frail or immunosuppressed patient, or an institutional cluster suggests crusted scabies and needs urgent clinician-led care. Fever, tachycardia, malaise, painful warmth, rapidly expanding erythema, lymphangitis, honey-coloured crusts or purulent lesions suggest impetigo, cellulitis or invasive infection. Facial or periorbital involvement, eye exposure to a chemical, breathing difficulty, facial swelling, seizure, collapse or ingestion of a pesticide requires emergency assessment. Severe treatment burning, blistering or widespread urticaria is a reason to stop the product and seek advice, not to apply more. Reconsider the diagnosis if there are no typical lesions or affected contacts, if hair or nails are the main site, or if a rash follows a new medicine. Persistent itch alone in the first fortnight is not a red flag for viable mites, but new burrows or new symptomatic contacts are. In pregnancy, infants, older adults and people with chronic skin disease, use a lower threshold for review because dosing, application and alternative diagnoses are less straightforward. Do not delay assessment of secondary infection while debating whether a household has completed laundering.
Indian Clinical Context
Indian households and services vary from dense urban accommodation to rural homes with limited hot water, washing machines or private consultation space. Explain that the essential public-health intervention is simultaneous treatment of the patient and relevant close contacts, not expensive whole-house spraying. Recently used clothes, towels and bedding can be washed and thoroughly dried; non-washable items can be sealed as advised. Sun-drying may be practical, but do not promise that sunlight alone sterilises every item. Check the concentration and licence of locally available permethrin, benzyl benzoate or sulfur products; brand names and access differ, and a pharmacy substitution can change strength. CDSCO information, the current package insert and local institutional formulary should take precedence over a US label. Oral ivermectin may be easier to deliver in an outbreak but is not suitable for pregnancy or children below 15 kg and should be prescribed by a trained clinician. Do not infer neglect from scabies in a child; offer discreet school or anganwadi communication and support. In hostels, shelters and care homes, coordinate contact assessment and cleaning with the responsible service. India-specific prevalence or regional claims should be checked before publication; this guide therefore emphasises transferable safety principles rather than invented local statistics.
NMC Competency Mapping
This topic supports NMC competency-based learning in dermatology, paediatrics, community medicine, pharmacology, communication and infection prevention. A learner should recognise a typical distribution and nocturnal itch, identify burrows and genital nodules respectfully, distinguish nits or dermatitis from scabies, and explain why asymptomatic close contacts may still need simultaneous treatment. The learner should screen for crusted disease, secondary bacterial infection, pregnancy, age and weight before discussing medicine choices. They should demonstrate safe counselling: body coverage, repeat timing, hand reapplication, eye avoidance, laundry priorities, avoidance of toxic home remedies and a clear return plan. Pharmacology assessment should test contraindications and uncertainty rather than brand memorisation. Community-medicine assessment can use a household or hostel cluster scenario, asking the learner to map contacts and practical environmental measures without recommending fumigation. Students should state that oral ivermectin is not an automatic answer in pregnancy or a child under 15 kg, and that crusted disease requires escalation. Local colleges should map the guide to the current NMC curriculum and institutional SOP rather than treating this narrative as a substitute for them.
Key Exam Pearls for NEET PG
Scabies is caused by Sarcoptes scabiei var hominis. Severe nocturnal itch, burrows in finger webs or wrists, genital nodules and affected contacts are high-yield clues. Infants can have palms, soles, scalp and widespread disease; crusted scabies may have enormous mite burden but little itch. Diagnosis is usually clinical; a negative scraping does not exclude it. Treat the patient and close household contacts together, repeat topical treatment according to the product because eggs may survive, and use reasonable laundering or bagging rather than fumigation. Permethrin 5% is a common topical first-line option. Oral ivermectin is weight-based, clinician directed and not for pregnancy or children under 15 kg; public-health MDA dosing must not be copied as an individual prescription. Crusted scabies needs combined topical and oral treatment under specialist or infection-control supervision. Persistent itch for one to two weeks can be post-scabetic; new burrows or new contacts suggest reinfestation or failure. Fever, cellulitis, rapidly spreading redness or systemic illness signals secondary infection. Kerosene, agricultural insecticide and unlabelled mixtures are dangerous, not alternatives.
Frequently Asked Questions
How should a person decide whether this needs emergency care?
Thick crusted or hyperkeratotic plaques, widespread scaling, little itch despite extensive disease, nail involvement, a frail or immunosuppressed patient, or an institutional cluster suggests crusted scabies and needs urgent clinician-led care. Fever, tachycardia, malaise, painful warmth, rapidly expanding erythema, lymphangitis, honey-coloured crusts or purulent lesions suggest impetigo, cellulitis or invasive infection. Facial or periorbital involvement, eye exposure to a chemical, breathing difficulty, facial swelling, seizure, collapse or ingestion of a pesticide requires emergency assessment. Severe treatment burning, blistering or widespread urticaria is a reason to stop the product and seek advice, not to apply more. Reconsider the diagnosis if there are no typical lesions or affected contacts, if hair or nails are the main site, or if a rash follows a new medicine. Persistent itch alone in the first fortnight is not a red flag for viable mites, but new burrows or new symptomatic contacts are. In pregnancy, infants, older adults and people with chronic skin disease, use a lower threshold for review because dosing, application and alternative diagnoses are less straightforward. Do not delay assessment of secondary infection while debating whether a household has completed laundering. Seek clinician assessment rather than relying on online self-diagnosis, and take the product list or medicine history to the service.
What is the most important mistake to avoid?
Confirm the working diagnosis, explain transmission without blame and plan treatment for the patient and relevant household or close contacts at the same time. Follow the exact local product label. Permethrin 5% is a commonly used first-line topical option; apply to every prescribed body area, leave for the labelled period and repeat at the labelled interval because eggs may survive. Children may need head and neck coverage according to age-specific guidance; avoid eyes and mouth. Oral ivermectin can be considered by a clinician for suitable adults or for outbreaks, but safety is not established in pregnancy or children under 15 kg. Crusted scabies requires urgent specialist-led combination therapy with frequent topical treatment, oral ivermectin schedules selected for severity and removal of crust to improve penetration; isolate or use contact precautions as locally advised. Treat bacterial superinfection only when signs support it. Wash or hot-dry recently used clothing, towels and bedding; bag items that cannot be washed for the recommended period. Ordinary deep fumigation is unnecessary and dangerous. Recheck if new burrows appear, contacts remain symptomatic or infection develops. Residual itch can be managed with emollient and clinician-selected antipruritic therapy after active scabies is addressed. Do not delay escalation when symptoms are sudden, severe, progressive or associated with systemic illness.
Why are household or partner measures part of treatment?
Indian households and services vary from dense urban accommodation to rural homes with limited hot water, washing machines or private consultation space. Explain that the essential public-health intervention is simultaneous treatment of the patient and relevant close contacts, not expensive whole-house spraying. Recently used clothes, towels and bedding can be washed and thoroughly dried; non-washable items can be sealed as advised. Sun-drying may be practical, but do not promise that sunlight alone sterilises every item. Check the concentration and licence of locally available permethrin, benzyl benzoate or sulfur products; brand names and access differ, and a pharmacy substitution can change strength. CDSCO information, the current package insert and local institutional formulary should take precedence over a US label. Oral ivermectin may be easier to deliver in an outbreak but is not suitable for pregnancy or children below 15 kg and should be prescribed by a trained clinician. Do not infer neglect from scabies in a child; offer discreet school or anganwadi communication and support. In hostels, shelters and care homes, coordinate contact assessment and cleaning with the responsible service. India-specific prevalence or regional claims should be checked before publication; this guide therefore emphasises transferable safety principles rather than invented local statistics. A plan that ignores contacts and access barriers commonly fails, so ask the treating team for practical support.
When is follow-up needed after initial treatment?
Refer for diagnostic uncertainty, an infant or very young child, pregnancy or breastfeeding, extensive eczema, immunosuppression, frailty, neurologic disease, treatment failure after correctly performed courses, or suspected crusted scabies. Arrange urgent review for fever, rapidly spreading redness, severe pain, pus, facial swelling, dehydration or an unwell child because bacterial infection may require different care. Crusted scabies should be escalated promptly to dermatology, medicine or an infection-control-capable service; assess close contacts and the care environment. A patient who cannot apply treatment safely because of disability, cognitive impairment, homelessness or limited support needs practical assistance, not repeated prescriptions. Consider sexual-health advice when genital lesions or close sexual contacts create uncertainty, while protecting confidentiality. In India, refer or coordinate with the nearest government dermatology, primary-health or district service when a regulated product is unavailable or the household cannot complete the plan. Review persistent itch rather than automatically escalating medicines: dermatitis, tinea, drug eruption, reinfestation and incorrect application are common explanations. Provide a written date for reassessment and explain that post-treatment itch may last one to two weeks. Avoid school or work exclusion beyond local policy; focus on treatment, privacy and contact support. Follow the named review interval, and return sooner for any red flag or a worsening trajectory.
Inside MedNext for this topic
- 411 MedNext-authored chapters
- 80,000+ MCQ bank
- 15 study modes
- a growing library of visual revision sheets
Study modes
- Notes
- MCQ
- Audio
- Video
- Visual
- 3D Anatomy
- Trace
- Flashcards
- Mnemonics
- Image Bank
- Clinical
- Microscopy
- Audio QBank
- Cadaver
- Book Match
Continue reading
Clinical GuidesAll Clinical Guides
Browse all clinical management guides for Indian medical practice.
Test your knowledge
Attempt structured MCQs on this topic to consolidate your understanding and connect the guide to exam-focused practice.
Try MCQs on this topic