© Springer Nature Switzerland AG 2021

P. Treadwell et al. (eds.)Atlas of Adolescent Dermatologyhttps://doi.org/10.1007/978-3-030-58634-8_8

8. Scabies

Julie Prendiville¹  

(1)

Department of Pediatrics, University of British Columbia, Vancouver, BC, Canada

 

 

Julie Prendiville

Email: jprendiville@sidra.org

Keywords

ScabiesSarcoptes scabieiMiteScybalaBurrowsScabicidePermethrinCrusted scabiesIvermectin

8.1 Introduction

Scabies is an infestation by the Sarcoptes scabiei var. hominis mite.

8.2 Epidemiology

Scabies is transmitted by close human physical contact, or sharing of beds. It occurs worldwide and affects all age groups. The pruritic inflammatory eruption is a response to the presence of mites and their products in the skin. Clinical signs and symptoms develop approximately 4 weeks after first contact.

8.3 Clinical Findings

The pathognomonic burrows (Fig. 8.1) are found on the hands, typically the web spaces, volar wrists, feet, axillary folds, and male genitalia. A variable generalized papular, eczematized dermatitis (Fig. 8.2) occurs on the trunk and limbs. Scabies nodules and vesicular lesions are more common in young children. Excoriation can lead to secondary impetigo. Crusted scabies is a rare and highly contagious variant (Fig. 8.3).

Fig. 8.1

Linear burrow – pathognomonic for scabies

Fig. 8.2

Dermatitis seen in scabies on the palms

Fig. 8.3

Crusted scabies

8.4 Laboratory

A diagnosis of scabies is confirmed by microscopic identification of the mite, eggs, or scybala (Fig. 8.4). The mite may be visualized within a burrow by dermoscopy.

Fig. 8.4

Microscopic preparation showing mite, egg, and scybala

8.5 Treatment

Application of a topical scabicide such as permethrin 5% cream or lotion for 10–12 hours and repeated in 1 week. Treatment must cover the entire body, including the neck and behind the ears. All household members and close contacts should be treated concurrently, whether symptomatic or not. Antibiotics may be required for secondary infection. Crusted scabies requires treatment with oral ivermectin in addition to topical therapy.

8.6 Prognosis

The prognosis is good if the patient and all contacts are treated appropriately and concurrently. Skin inflammation may persist for 1–4 weeks and require treatment with a topical steroid. Nodules may sometimes persist for several months.

Suggested Reading

1. Thomas C, Coates SJ, Engelman D, et al. Ectoparasites: scabies. J Am Acad Dermatol. 2020;82:533–48.