Photodistributed eruptive telangiectasias: an uncommon adverse drug reaction. A retrospective case series.

Drug-induced photodistributed telangiectasia (PT) is a cutaneous adverse effect (AE) resulting from the interaction of ultraviolet radiation with pharmacotherapy. Reports of PT in the literature are scarce. We report 25 cases of drug-induced PT highlighting the potential relationship between the onset of skin lesions, drug intake and photo exposure. We alert practitioners that PT is a possible dermatological phototoxic AE of many drugs.

Early and Late Onset Side Effects of Photodynamic Therapy.

Photodynamic Therapy (PDT) is a non-invasive treatment successfully used for neoplastic, inflammatory and infectious skin diseases. One of its strengths is represented by the high safety profile, even in elderly and/or immuno-depressed subjects. PDT, however, may induce early and late onset side effects. Erythema, pain, burns, edema, itching, desquamation, and pustular formation, often in association with each other, are frequently observed in course of exposure to the light source and in the hours/days immediately after the therapy. In particular, pain is a clinically relevant short-term complication that also reduces long-term patient satisfaction. Rare complications are urticaria, contact dermatitis at the site of application of the photosensitizer, and erosive pustular dermatosis. Debated is the relationship between PDT and carcinogenesis: the eruptive appearance of squamous cell carcinoma (SCC) in previously treated areas has been correlated to a condition of local and/or systemic immunosuppression or to the selection of PDT-resistant SCC. Here we review the literature, with particular emphasis to the pathogenic hypotheses underlying these observations.

Challenging diagnosis of peripillous sheaths.

Peripillous sheaths, or hair casts, are asymptomatic, white, cylindrical concretions that encircle the hair without adhering to it. They are infrequently documented in the literature, are often misdiagnosed, and generate avoidable apprehension and expense for parents and caregivers. Dermoscopy is the standard for a rapid, noninvasive, cost-effective diagnosis. We describe a case of peripillous sheaths presenting in a boy.