Case Report
Recurrent UVA Photosensitive Erythema Multiforme
Patricia L . Danielsen 1 , Hans C . Wulf 2 , Claus Zachariae 1 , R . Henrik-Nielsen 3 and Kristian Kofoed 1
Departments of Dermatology , 1 Gentofte University Hospital and 2 Bispebjerg University Hospital , and
3
Department of Pathology , Bispebjerg University Hospital , Copenhagen , Denmark
Recurrent erythema multiforme ( EM ) causes substantial morbidity . Diagnosis and treatment are often prolonged and challenging . EM is most often related to herpes simplex virus ( HSV ), but other infections or systemic drugs can be implicated ( 1 ). Although the classic “ target lesion ” is an essential criterion for diagnosis , an atypical form , presenting with irregular-shaped blisters , has been described ( 2 ). This case report describes the clinical presentation , diagnosis and treatment of recurrent photosensitive erythema multiforme ( PEM ) presenting with typical “ targets ” and irregular blisters .
A 32-year-old woman presented at the acute referral unit of the Department of Dermatology , Gentofte University Hospital , Copenhagen , in late May 2014 . She had had large bullae for 1 month , which had developed after a 1-week holiday in Egypt , where she had been exposed to the sun . After her return she had been very cautious concerning sun protection but new bullae were still developing . She did not take any prescription medication or over-the-counter drugs . Her medical history revealed no other complaints .
On clinical examination classical target lesions with central crusts were identified on the medial aspect of her left orbital area without involvement of sclera or conjunctiva . There was bilateral involvement of the nasal mucous membrane with oedema , inflammation and crusts . The right arm presented with a firm , large , fluid-filled bulla and a target lesion ( Fig . 1A ). The dorsal side of the hands and feet showed target lesions with central erosions ( Fig . 1B ). Culture of a throat swab was negative for haemolytic streptococci , expectorate was negative for Mycoplasma pneumoniae DNA , and bullae fluid was negative for herpes simplex DNA . Laboratory tests showed mild leucocytosis ( 10.4 × 10 9 / l ), in which neutrophils were predominant ( 8.13 × 10 9 / l ) and C reactive protein ( CRP ) 56 mg / l . Liver function tests were normal .
The woman had had similar rashes since she was a teenager , and a previous skin biopsy had shown subepidermal bulla with lymphocytes and epidermal apoptoses ( Fig . 2 ). Over the years numerous swabs for herpes simplex had all tested negative and prophylactic treatment with acyclovir did not prevent new attacks . A photo provocation test induced oedema and erythema “ en cocarde ” inside and outside areas exposed to ultraviolet A ( UVA ) ( 3 standard erythema doses ( SED )), but not to ultraviolet B ( UVB ) ( 2 SED ).
Prednisolone , 37.5 mg / daily , was administered for 10 days and the blisters were lanced . The patient was advised to avoid sun exposure and to use sunscreen with a high UVA filter . The lesions healed without scarring and no new lesions appeared .
Recurrent vesiculobullous EM is a form of EM major that is most often triggered by HSV , and more seldom M . pneumonia or hepatitis C virus . Unfortunately in most cases the inciting factor is not identified ( 1 ).
Fig . 1 . Bullous and target lesions on : ( A ) the dorsal right arm , and ( B ) the feet in a woman with ultraviolet A ( UVA ) -induced erythema multiforme .
Forum for Nord Derm Ven 2016 , Vol . 21 , No . 4 103