A spider bite may represent a possible causative factor of AGEP. A spider's venom contains sphingomyelinase that stimulates the release of IL8 and GM-CSF, which are involved in AGEP pathogenesis. Whether or not the con-current use of antibiotics has an effect in AGEP appearance when combined with a spider's venom, cannot be excluded.

Background: Gadolinium chelates are relatively safe contrast media used in MRI. Immediate severe adverse effects are exceptionally rare and mostly concern mild anaphylactoid reactions. We report a case of anaphylaxis to gadobenate dimeglumine (Gd-BOPTA, Multihance®), a gadolinium-based contrast agent. Methods: A 32-year-old female patient with a personal history of multiple sclerosis, while undergoing an MRI scan, developed bronchospasm and acute urticaria with diffuse giant pruritic plaques in the first minute of Gd-BOPTA infusion. The procedure was cancelled and acute treatment of the reaction took place. The patient reported 2 additional MRI scans with definite use of unknown contrast media in the past 2 years without any adverse effect. Blood samples were obtained 2 and 48 h after the reaction for measurement of serum tryptase concentration (Pharmacia Diagnostics, Uppsala, Sweden). Skin prick tests and intradermal tests were performed using 1:1,000, 1:100 and 1:10 dilution of the offending agent and alternative gadolinium-based agents [gadodiamide (Omniscan®) and gadoteric acid (Dotarem®)]. A group of 10 nonatopic individuals who underwent the same skin testing comprised the control group. Results: Tryptase concentration was highly elevated 2 h after the reaction (21 µg/l) compared with that at 48 h (3 µg/l). Skin prick tests in our patient were all negative, while intradermal testing with 0.03 ml of 1:100 and 1:10 preparations of Multihance showed a definite positive wheal-and-flare reaction. Skin tests to the alternative agents showed no response. In the control group, all performed tests were negative. Conclusion: We report the first case of an allergic reaction to gadobenate dimeglumine. Besides, skin testing seems to be a precious diagnostic tool which, if positive, strongly suggests a mast cell-mediated underlying mechanism.

Sodium fluorescein (SF) is widely used to assess chorioretinal disorders. Adverse reactions are well documented but the underlying mechanism is still uncertain. The aim of this study was the evaluation of skin testing to predict SF reaction, the identification of possible predisposing factors, and the objective record of the reported reactions. All patients with adequate indication for SF angiography (SFA) during an 18-month period were evaluated as follows: (a) detailed personal history of atopy, diabetes, previous SFA, and/or diagnostic procedures with radiocontrast media (RCM) and possible side effect; (b) skin testing with SF 10% diluted preparations; (c) SFA with 5 mL of SF, objective record of any reaction. Two hundred twenty-four patients (108 men and 116 women) with a mean age of 65.2 years (SD, 12.86; range, 16-92 years) underwent SFA. The overall rate of adverse reactions was 3.6% (8/224), which consists of 5 (2.2%) individuals with transient mild nausea; 2 (0.9%) subjects with face and upper trunk flushing that appeared in one case after 60 minutes and in the other case 24 hours later and both resolved without treatment, and I subject with transient bilateral frontal headache and dizziness. None of the 224 patients had positive skin or intradermal testings. One hundred thirty-six of 224 (60.7%) patients stated no previous SFA and 74.1% had not performed RCM injection. None of the recorded variables correlated with increased risk of reaction. SFA is a safe procedure with minor adverse effects. Although in vivo testing can not identify reactors it may help to exclude an underlying IgE-mediated mechanism in susceptible individuals.