Table 2.

Case definitions for scabies using the 2020 IACS Criteria³⁸

Criteria category		Used in survey
Confirmed scabies
	At least one of the following:
A1	Mites, eggs or faeces on light microscopy of skin samples	No
A2	Mites, eggs or faeces visualised on an individual using a high-powered imaging device	No
A3	Mite visualised on an individual using dermoscopy	No
Clinical scabies
	At least one of the following:
B1	Scabies burrows	No
B2	Typical lesions affecting male genitalia	No
B3	Typical lesions in a typical distribution and two history features*	Yes
Suspected scabies
	At least one of the following:
C1	Typical lesions in a typical distribution and one history feature*	Yes
C2	Atypical lesions or atypical distribution and two history features*	Yes

Diagnosis can be made at one of the three levels (A, B or C). A diagnosis of clinical or suspected scabies should only be made if other differential diagnoses are considered less likely than scabies.

*History features include (i) itch and (ii) positive contact history.

IACS, International Alliance for the Control of Scabies.