Discoid Lupus Erythematosus Lesions Associated with Systemic Fluorouracil Agents: A Case Report and Review

Drug-Induced Photosensitivity: Clinical Types of Phototoxicity and Photoallergy and Pathogenetic Mechanisms

Drug-induced photosensitivity (DIP) is a common cutaneous adverse drug reaction, resulting from the interaction of ultraviolet radiations, mostly ultraviolet A, with drugs. DIP includes phototoxicity and photoallergy. A phototoxic reaction is obtained when topical and systemic drugs or their metabolites absorb light inducing a direct cellular damage, while a photoallergic reaction takes place when the interaction between drugs and ultraviolet radiations causes an immune cutaneous response. Clinically, phototoxicity is immediate and appears as an exaggerated sunburn, whereas photoallergy is a delayed eczematous reaction. DIP may show several clinical subtypes. In this mini-review we report the pathogenetic mechanisms and causative drugs of DIP. We offer a detailed description of DIP clinical features in its classical and unusual subtypes, such as hyperpigmentation/dyschromia, pseudoporphyria, photo-onycolysis, eruptive teleangiectasia, pellagra-like reaction, lichenoid reaction, photodistributed erythema multiforme and subacute/chronic cutaneous lupus erythematosus. We described how physicians may early recognize and manage DIP, including diagnostic tests to rule out similar conditions. We made suggestions on how to improve sun exposure behaviors of patients at risk of DIP by means of an aware use of sunscreens, protective clothing and recent technologic tools. We highlighted the lack of sun safety programs addressed to patients at risk of DIP, who need a formal education about their condition.

Unusual severe radiation-induced toxicity in a patient with discoid lupus erythematosus: A case report and critical review of the literature

Data on the incidence and severity of radiation-induced toxicity in patients with systemic and/or cutaneous lupus erythematosus (SLE/CLE) are very limited. After reporting the case of a patient who experienced major toxicity and CLE flare in the irradiated area following breast irradiation, we conducted a comprehensive literature review of available data in this setting. The few retrospectives studies which have evaluated both the risk of toxicity in SLE/CLE patients and/or the potential induction or reactivation of SLE/CLE with radiotherapy have not shown differences between SLE/CLE patients and controls. Several other factors such as concurrent chemotherapy, a particular genetic background, or lupus treatments (essentially hydroxychloroquine) can explain severe radiation-induced toxicity. Therefore, patients with SLE/CLE should be irradiated like patients without SLE/CLE, with close monitoring during radiotherapy if other risk factors exist. Further studies examining a larger number of patients would probably allow a better understanding of the radiosensitivity of these patients.