- In adults, usually during sex
- Not shaking hands, hugging with clothes on, or sitting on a couch
- Competitive wrestling or similar activities
- Families with young children may transmit among each other (constant contact)
- Time to develop hypersensitivity to mites eggs & feces
- If previously sensitized, reaction can start right away
Lesions: Appearance is quite variable
- Unimpressive papules, but also pustules, vesicles, nodules, or wheals
- Commonly excoriated, sometimes with secondary impetigo or furuncles
- Typically on & between fingers, volar wrists, axilla, periumbilical, waist, & buttocks
- Almost always present near breast areola in women, on penis or scrotum in men
- Virtually never on the back or head (except infants)
- NOT only on exposed areas [suspect bug bites]
Pathognomonic burrow (mite’s current trail):
- faint thin gray / brownish line
- Maybe a barely-perceivable dot at an end (the mite).
- Burrows are rarely noted (eaasily scratched away)
Diagnostic Technique (easiest & maybe best): sticky transparent packing tape
- Press hard against a lesion, pull off rapidly, examine under low power microscopy
- Look for mite eggs & feces (see Picture)
- Need lots of specimens. Positive clinches it, negative doesn’t rule it out
- Diffuse scales & crusts, millions of mites, very contagious, very hard to treat
- Often doesn’t itch (patients are too debilitated)
- May need a KOH prep to dissolve debris on top of the mites
Note: Treatment kills the mites immediately, but itching persists another few weeks
DiagnosisDude 