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A 32-year-old woman presented requiring contraception. She had previously had an Implanon® inserted, but this had been removed to allow her to become pregnant. Following her pregnancy she wished to use a long-term contraceptive method and requested another Implanon.
Following insertion of a Nexplanon® within 24 hours the site was red and inflamed. The redness was <0.5 mm around the outline of the subdermal Nexplanon. Antibiotics and antihistamines were given but the redness did not resolve. There were no features of spreading cellulitis; this was localised to the implant outline. Following 1 week of observation the localised reaction was no better. The patient complained that the site was painful. It was decided to remove the implant.
On removal of the implant there was no pus or sign of infection. It was easily removed as no capsule had developed. Following removal no further treatment was given and the redness settled within days.
The patient was given the option of a repeat procedure in the other arm or an alternative method of contraception, the understanding being that the previous adverse reaction was due to either infection or allergy. She chose to have a repeat insertion in her other arm. The same reaction occurred. The implant was removed and alternative contraception provided.
The constituents of Nexplanon are etonogestrel, barium sulphate and ethylene vinyl acetate copolymer. In this individual we know that previously Implanon had been well tolerated. Implanon contains the same constituents as Nexplanon except barium sulphate. The patient was informed that she is allergic to barium sulphate. The incidence of barium sulphate allergy is not clear. In one study allergy has been reported as 2 per million.1
I would like this example to serve as a reminder of an uncommon adverse event to Nexplanon insertion. It also raises the question of how best to manage such an event. Should a swab have been taken at the time of implant removal? Should the patient be referred for skin testing to determine the exact cause of clinical suspected allergy? Allergy to barium may have implications for future medical care (e.g. contrast media).
Competing interests None.
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