Radiocontrast Media Hypersensitivity: Skin Testing Differentiates Allergy From Nonallergic Reactions and Identifies a Safe Alternative as Proven by Intravenous Provocation.

BACKGROUND: Hypersensitivity reactions occurring within minutes after intravascular injection of iodinated radiocontrast media (RCM) are not rare and have been previously considered to be nonallergic. However, in the last decades, evidence is increasing that genuine RCM allergy may present as either full-blown anaphylaxis or delayed exanthematous skin reaction. OBJECTIVES: We aimed to assess whether allergy diagnostics including skin and provocation testing can differentiate between nonallergic and allergic RCM hypersensitivity by identifying the causative RCM as well as tolerated alternative RCM. METHODS: We retrospectively evaluated clinical and diagnostic data from 45 consecutive patients with RCM hypersensitivity. RESULTS: Immediate nonallergic RCM hypersensitivity was diagnosed in 21 patients, immediate-type RCM allergy in 11, delayed-type RCM allergy in 11, and delayed-type iodine allergy in 2. All patients with immediate-type RCM allergy had a history of moderate to severe anaphylaxis. Eleven of 13 patients with delayed-type allergic reactions including the 2 cases of iodine allergy suffered from maculopapular exanthem developing several hours to days after exposure, 1 was a systemic hypersensitivity syndrome, and 1 a fixed drug eruption. Of 18 RCM-allergic patients tested, all tolerated an alternative RCM in the intravenous provocation. CONCLUSIONS: The diagnostic sensitivity of intradermal RCM testing to identify allergic patients is high in both immediate-type and delayed-type RCM allergy. Intravenous provocation with a skin test-negative RCM is safe and enables identification of a tolerated alternative RCM. Additional skin testing of iodine solution is required to identify patients with iodine allergy.

Extensive molluscum contagiosum virus infection in a young adult receiving fingolimod.

Fingolimod-related viral infections have been described on several occasions since its introduction in 2010. We hereby add a report on an otherwise immunocompetent, 18-year old Caucasian man with relapsing-remitting multiple sclerosis who developed a protracted and extensive molluscum contagiosum (MC) virus infection shortly after being started on fingolimod. Wide-spread cutaneous MC infections in adult patients are considered indicative of underlying immunosuppression. Neurologists prescribing fingolimod ought to be aware of a possibly increased risk of MC, but also need to know about its relative benignity, lack of extra-cutaneous complications, and adequate treatment options.