SCAB (יַלֶּ֫פֶת, H3539, מִסְפַּ֫חַת, H5030; LXX Gr. σημασία; λείχην). A scab is a crust on a sore. Of itself it is not alarming, and in certain cases may even have a protective function. The important thing is the type of sore beneath the crust.

In OT days a person with a persistent scab was obliged to report to a priest, who would determine whether it was a non-progressive, temporary, benign condition, or something that required isolation (Lev 13:2-8).

Priests were disqualified for service, and sacrificial animals were rejected, if a scab was present. “Scabby mouth,” with sores around the lips, nose and eyelids of sheep is a condition known to veterinarians today and may well have been a familiar sight in the hot, dry climate of Israel.

The daughters of Zion were to be punished with scabs on the head (Isa 3:17) if the people failed to worship the Lord. We only have to think of a child with generalized, greasy, crusty cradle-cap (seborrheic dermatitis) to realize what a distressing, humiliating affliction this would be for a young woman.