title: A case of photocontact urticaria induced by photodynamic therapy with topical 5-aminolaevulinic acid.
abstract: Photodynamic therapy (PDT) with topical application of 5-aminolaevulinic acid (ALA) is a promising new treatment option for the management of various cutaneous malignancies. Generally, topical ALA-based PDT has relatively insignificant adverse effects of transient character; these include itching, stinging or burning pain and slight to moderate erythema. We describe the first case of photocontact urticaria induced by topical ALA-based PDT for the treatment of unilesional mycosis fungoides. Although the first treatment session resulted merely in mild erythema, the second PDT caused marked urticaria corresponding to the PDT-applied area with an intolerable stinging sensation. A photopatch test demonstrated that black light and visible light irradiation after topical ALA provoked an urticarial reaction in the patient's uninvolved skin. These observations suggested an allergic pathogenesis for the wheal formation induced by PDT with topical ALA in this case. Photocontact urticaria should be considered as a possible adverse effect in ALA-based PDT.
authors.affiliation: Department of Dermatology, Hirosaki University School of Medicine, 5 Zaifu-cho, Hirosaki, Aomori 036-8562, Japan.
authors.forename: Shohei
authors.initials: S
authors.lastname: Yokoyama
authors.forename: Hajime
authors.initials: H
authors.lastname: Nakano
authors.forename: Aya
authors.initials: A
authors.lastname: Nishizawa
authors.forename: Takahide
authors.initials: T
authors.lastname: Kaneko
authors.forename: Ken
authors.initials: K
authors.lastname: Harada
authors.forename: Katsumi
authors.initials: K
authors.lastname: Hanada
mesh_terms: D000287:Administration, Topical; D000368:Aged; D000622:Aminolevulinic Acid / Q000008:administration & dosage / Q000009:adverse effects*; D005260:Female; D006801:Humans; D009182:Mycosis Fungoides / Q000188:drug therapy; D010778:Photochemotherapy / Q000009:adverse effects*; D010787:Photosensitivity Disorders / Q000175:diagnosis / Q000209:etiology* / Q000473:pathology; D017319:Photosensitizing Agents / Q000008:administration & dosage / Q000009:adverse effects*; D012867:Skin / Q000473:pathology; D012878:Skin Neoplasms / Q000188:drug therapy; D014581:Urticaria / Q000175:diagnosis / Q000209:etiology* / Q000473:pathology
chemical_list: D017319:Photosensitizing Agents; D000622:Aminolevulinic Acid