Summary
Definition
History and exam
Key diagnostic factors
- herald patch
- pruritus
- age 10 to 35 years
- 2- to 12-week duration
- scale
- located on trunk and upper extremities
- fir-tree pattern distribution
- located on face, palms, soles, mucosa
- acute to sub-acute recurrent skin eruption
Other diagnostic factors
- 2-week timing between herald patch and new lesions
- female sex
- prodromal symptoms
- pigmentary alteration (severe cases/dark skin colour)
Risk factors
- age 10 to 35 years
- female sex
Diagnostic investigations
Investigations to consider
- skin biopsy
- antistreptolysin O titres
- potassium hydroxide (KOH) preparation microscopy or fungal culture
- rapid plasma reagin/Venereal Disease Research Laboratory
Treatment algorithm
mild-to-moderate symptoms
severe or refractory disease
refractory to all other treatments
Contributors
Authors
Daniela Kroshinsky, MD, MPH

Director of Inpatient Dermatology
Associate Professor of Dermatology
Massachusetts General Hospital
Harvard School of Medicine
Boston
MA
Disclosures
DK declares that she has no competing interests.
Peer reviewers
Eve Lowenstein, MD
Chief of Dermatology
Brookdale Hospital
Brooklyn
NY
Disclosures
EL declares that she has no competing interests.
Ladan Shahabi, MD
Fellow
Dermatology
University of Michigan
Ann Arbor
MI
Disclosures
LS declares that he has no competing interests.
John English, MBBS, FRCP
Consultant Dermatologist
Department of Dermatology
Queen's Medical Centre
Nottingham University Hospitals NHS Trust
Nottingham
UK
Disclosures
JE declares that he has no competing interests.
Differentials
- Secondary syphilis
- Guttate psoriasis
- Tinea corporis
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