Fast Five Quiz: What Do You Know About Eczema?

William James, MD


January 06, 2017

No biomarker for the diagnosis of AD is known. Laboratory testing is seldom necessary.

A swab of infected skin may help with the isolation of a specific organism (eg, Staphylococcus or Streptococcus) and antibiotic sensitivity. Allergy and radioallergosorbent testing is of little value. A swab for viral PCR may help identify superinfection with herpes simplex virus and identify a diagnosis of eczema herpeticum.

A complete blood cell count for thrombocytopenia helps exclude Wiskott-Aldrich syndrome, and testing to rule out other immunodeficiencies may be useful. This also helps identify peripheral eosinophilia, which may support the diagnosis. A serum IgE level can also support the diagnosis. Scraping to exclude tinea corporis is occasionally helpful.

For more on the workup of AD, read here.


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