Dermatologic Manifestations of Gianotti-Crosti Syndrome Workup

Updated: Nov 13, 2020
  • Author: Kara N Shah, MD, PhD; Chief Editor: William D James, MD  more...
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Approach Considerations

Diagnostic criteria for Gianotti-Crosti syndrome have been proposed and include the following [39, 40] :

  • The presence of all of the following positive clinical features:

    • Monomorphous, flat-topped, pink-brown papules or papulovesicles 1-10 mm in diameter

    • At least three of the following four sites involved: cheeks, buttocks, extensor surfaces of forearms, extensor surfaces of legs

    • Symmetric eruption

    • Duration of at least 10 days

  • The absence of extensive truncal lesions and scaling

  • Exclusion of alternative diagnoses as more compatible as based on clinical judgment

  • Compatible histopathologic findings, if skin biopsy is performed


Laboratory Studies

Laboratory studies are not generally indicated. Blood counts may reveal a lymphocytosis and a relative monocytosis or a lymphopenia secondary to an underlying viral infection, if present.

In cases associated with acute infection with the hepatitis B virus, EBV, or CMV, anicteric hepatitis is evident by elevations in the levels of hepatic transaminases and antiviral antibodies. A viral agent can be identified in approximately one third of cases. If a specific infectious etiology is suspected, testing can be directed at potential etiologies, as follows:

  • EBV - Monospot, immunoglobulin M (IgM) and immunoglobulin G (IgG) titers, or serum polymerase chain reaction (PCR)

  • CMV - IgM and IgG titers, serum CMV antigen levels, or serum PCR

  • RSV, parainfluenza virus, other respiratory viral pathogens - Nasal washing for fluorescent antibody testing or PCR

  • Enterovirus - Culture or PCR from serum

  • Parvovirus B19 - IgM and IgG titers or serum PCR

  • HHV-6 - Serum PCR

  • Group A beta-hemolytic streptococci - Serum PCR or pharyngeal culture


Histologic Findings

The histology of skin biopsy specimens is nonspecific. Mild epidermal acanthosis and spongiosis with focal parakeratosis can be seen. A lymphocytic exocytosis may also be seen. Edema of the papillary dermis and a superficial lymphohistiocytic infiltrate, sometimes with a perivascular localization or a lichenoid appearance, is common. Rarely, features of a lymphocytic vasculitis have been noted.