The Potential for a Blood Test for Scabies.
BACKGROUND
Scabies afflicts millions of people worldwide, but it is very difficult to diagnose by the usual skin scrape test, and a presumptive diagnosis is often made based on clinical signs such as rash and intense itch. A sensitive and specific blood test to detect scabies would allow a physician to quickly make a correct diagnosis.


OBJECTIVE
Our objective was to profile the mite-specific antibodies present in the sera of patients with ordinary scabies.


METHODS
Sera of 91 patients were screened for Ig, IgD, IgE, IgG and IgM antibodies to S. scabiei, as well as to the house dust mites Dermatophagoides farinae, D. pteronyssinus and Euroglyphus maynei.


RESULTS
45%, 27% and 2.2% of the patients had measurable amounts of mixed Ig, IgG and IgE that recognized scabies mite antigens. However, 73.6% of the scabies patients had serum IgM that recognized scabies proteins, and all except two of them also had IgM that recognized all of the three species of dust mites. No patient had serum antibody exclusively reactive to scabies mite antigens.


CONCLUSIONS
Co-sensitization or cross-reactivity between antigens from scabies and house dust mites confounds developing a blood test for scabies.
Department of Biological Sciences, Wright State University, Dayton, Ohio, United States of America.
Larry G
LG
Arlian
Institute of Microbiology and Hygiene, Charité University Medicine, Berlin, Germany.
Hermann
H
Feldmeier
Department of Biological Sciences, Wright State University, Dayton, Ohio, United States of America.
Marjorie S
MS
Morgan
D000293:Adolescent; D000328:Adult; D000368:Aged; D000818:Animals; D000906:Antibodies / Q000097:blood; D002648:Child; D002675:Child, Preschool; D003429:Cross Reactions; D005260:Female; D006403:Hematologic Tests / Q000379:methods*; D006801:Humans; D008297:Male; D008875:Middle Aged; D012520:Sarcoptes scabiei / Q000276:immunology*; D012532:Scabies / Q000175:diagnosis* / Q000276:immunology*; D012680:Sensitivity and Specificity; D012698:Serologic Tests / Q000379:methods*; D055815:Young Adult
D000906:Antibodies