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Photosensitive erythema multiforme and erythema multiforme-like polymorphous light eruption.
P G Calzavara Pinton1, M Venturini, R Capezzera
1Department of Dermatology, Spedali Civili, Brescia, Italy Institute of Pathology, University of Brescia, Italy. calzavar@bshosp.osp.unibs.it
Photodermatology, Photoimmunology & Photomedicine
|August 14, 2003
Summary
Photosensitive erythema multiforme (EM) is a rare skin condition triggered by sunlight. This case study details a patient with recurrent EM eruptions, confirmed by phototesting, highlighting its distinct presentation.
Area of Science:
- Dermatology
- Photobiology
- Immunology
Background:
- Photosensitive erythema multiforme (EM) is an uncommon disorder.
- Typically, EM is associated with preceding herpes virus infection or drug ingestion before sun exposure.
- This case presents a patient with a distinct history and presentation.
Observation:
- A 37-year-old male experienced recurrent EM eruptions over 20 years, primarily on sun-exposed skin.
- Lesions also affected unexposed skin and oral mucosa.
- The patient reported poor sun tolerance and denied herpes simplex virus (HSV) infection or drug use.
Findings:
- Provocative phototesting elicited clinically and histologically similar lesions.
- Low-dose UVA (10 J/cm2) and UVB (100 mJ/cm2) induced the characteristic eruptions.
- Diagnosis of photosensitive EM was confirmed through clinical, histological, and phototesting results.
Implications:
- This case expands the understanding of photosensitive EM presentations.
- It underscores the importance of phototesting in diagnosing such conditions.
- Differential diagnosis includes the EM-like variant of polymorphous light eruption.