Last reviewed: 8 Sep 2024
Last updated: 28 Jan 2021
Summary
Definition
History and exam
Key diagnostic factors
- target lesions of the extremities
- recurrent disease
- mucosal erosions
Full details
Other diagnostic factors
- targetoid lesions
- rapid onset of lesions
- self-limiting course
- clustered vesicles on an erythematous base
- rhonchi, rales, and/or wheezes
- red tympanic membranes
- hepatomegaly
Full details
Risk factors
- prior occurrence
- herpes simplex virus (HSV) infection
- cytomegalovirus (CMV) infection
- Epstein-Barr virus (EBV) infection
- Mycoplasma pneumonia
- hepatitis B virus infection
- histoplasmosis
- HIV infection
- lymphoma
- orf virus infection
- medications
- tattoos
- hepatitis B vaccine
- syphilis
Full details
Diagnostic tests
1st tests to order
- CBC
- serum electrolytes
- herpes simplex virus (HSV) serology
- rapid polymerase chain reaction (PCR)
- cold-hemagglutination serology
- M pneumoniae titers
- CXR
- autoantibody titers
Full details
Tests to consider
- hematoxylin and eosin biopsy
- immunofluorescence biopsy
- hepatitis B virus (HBV) serology
- LFTs
Full details
Emerging tests
- antidesmoplakin antibodies
Treatment algorithm
ACUTE
EM minor
EM major
ONGOING
recurrent EM
Contributors
Authors
Areta Kowal-Vern, MD
Adjunct Research Faculty
Arizona Burn Center
Maricopa Integrated Health Systems
Phoenix
AZ
Disclosures
AK-V declares that she has no competing interests.
Acknowledgements
Dr Areta Kowal-Vern would like to gratefully acknowledge Dr Jonathan Silverberg and Dr Nanette Silverberg, the previous contributors to this topic.
Disclosures
JS and NS declare that they have no competing interests.
Peer reviewers
Cristine Radojicic, MD
Staff Physician
Cleveland Clinic
Cleveland
OH
Disclosures
CR declares that she has no competing interests.
Brian Swick, MD
Clinical Assistant Professor
University of Iowa College of Medicine
Iowa City
IA
Disclosures
BS declares that he has no competing interests.
Differentials
- Urticaria
- Polymorphous light eruption (PMLE)
- Subacute cutaneous lupus erythematosus
More DifferentialsGuidelines
- Diagnosis and treatment of adults with community-acquired pneumonia
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