Is the variability of nickel patch test reactivity over time associated with fluctuations in the systemic T-cell reactivity to nickel?

Nickels and tines: the myth of nickel allergy in intracranial stents

BACKGROUND

Most intracranial stents contain nickel alloy, and nickel allergy or hypersensitivity is common. Neurological injury following endovascular treatment with a nickel containing intracranial stent has been reported in patients with purported nickel allergy, but it is unclear whether these reactions represent true nickel hypersensitivity. We quantified nickel release from commonly used intracranial stents to investigate whether such stents should be avoided in patients with nickel allergy.

METHODS

We examined nickel release from seven commonly used intracranial stents: Enterprise, LVIS Jr, Neuroform, Wingspan, Zilver, Pipeline Flex Embolization Device, and Surpass Evolve. We incubated each stent in human plasma-like media for 30 days. Dimethylglyoxime (DMG) spot testing was performed on each stent to detect released nickel at 0 and 30 days. Inductively coupled plasma-optical emission spectroscopy (ICP-OES) was then used to quantify the nickel concentration of the media at 30 days. Nickel currency and nickel standard for atomic absorption spectrometry were used as positive controls.

RESULTS

DMG spot tests indicated nickel release only from nickel currency at 0 and 30 days of incubation. No nickel release was detected from any stent at 30 days using ICP-OES.

CONCLUSIONS

Nickel release from commonly used intracranial stents is negligible. These results suggest that previously reported hypersensitivity to these stents may be misattributed to nickel allergy, and that patients with nickel allergy may be safely treated with select nickel-containing stents.

A Retrospective Study of Aimed Patch Testing With Aqueous Nickel Sulfate Hexahydrate at 30% and 15% in Patients With Dermatitis

BACKGROUND

Sometimes, patients with a history of metal intolerance react negatively or doubtfully to nickel at patch testing.

OBJECTIVE

The aim of the study was to investigate whether aqueous nickel sulfate hexahydrate at 15% and 30% traces more contact allergy than the nickel preparation in the baseline series at 5%.

METHODS

In the period 1995-2015, more than 800 of 16,059 patients with a negative or doubtful patch test reaction to the petrolatum preparation of nickel at 5% on the day 3 reading were additionally tested with aqueous nickel at 15% and/or 30%.

CONCLUSIONS

In this retrospective study with aimed patch testing with aqueous nickel solutions, significantly more (P < 0.001) contact allergy was obtained as compared with the 5% preparation in petrolatum. The 30% solution was significantly better (P < 0.001) than the 15% solution. To demonstrate that patch testing with nickel at 15% or 30% is better than the present testing with 5% requires simultaneous testing with the 3 nickel preparations.