Scabies is a highly communicable skin disease caused by infestation with a host-specific mite. Transmission requires close personal, skin-to-skin contact, though contact with used, unwashed bedding and clothing from an affected individual can also result in infection.
Clinical Concept: Scabies mites tend to burrow in areas of warmth, such as the finger webs, axillary folds, belt line, areolae, scrotum, penis, and under the breasts. Lesions typically develop and cluster within these specific anatomic sites.
Scabies lesions often begin as characteristic burrows, which typically progress into vesicular or papular forms with excoriation caused by scratching. Distribution and lesion appearance vary depending on patient age and duration of infestation:
Diagnosis is made clinically based on patient health history and physical examination, focusing on the characteristic lesions and their typical distribution pattern. Confirmation can be achieved through microscopic examination of skin scrapings, which allows direct identification of mites, larvae, ova, and fecal matter.
First-line therapy focuses on targeted topical scabicides alongside thorough environmental cleaning to prevent reinfection:
| Intervention Type | Treatment / Action | Instructions & Clinical Notes |
|---|---|---|
| First-Line Therapy | Permethrin 5% (Elimite®) Lotion | Preferred treatment. Apply thoroughly and leave on for 8 to 14 hours before showering or bathing. |
| Second-Line / Discontinued | Lindane (Kwell®) | Not recommended: Carries significant risks of neurotoxicity and seizures, with lower efficacy. Absolutely contraindicated in pregnant women, children, and elderly patients. |
| Environmental Control | Hot water washing or dry heat cycle | Wash bedclothes and personal items in hot water or run through a dryer cycle. Alternatively, seal items in plastic storage bags for at least 1 week (mites die within 3–4 days without host contact). |
Even after effective permethrin therapy, patients often experience persistent, severe pruritus. This occurs because dead mites and residual waste material trapped within the skin trigger a prolonged inflammatory reaction until the body naturally sheds the debris over several weeks.
To alleviate post-scabietic itching, clinicians should offer:
1. Barry M. Scabies. Medscape.
2. Gunning K, Pippitt K, Kiraly B, et al. Pediculosis and scabies: treatment update. Am Fam Physician. 2012;86(86):535–541.
3. James WD, Berger TG, Elston DM. Andrews’ Diseases of the Skin: Clinical Dermatology. 12th ed. Philadelphia, PA: Elsevier; 2016:445–447.
