Levonorgestrel-Releasing Intrauterine System Causes a Lichenoid Drug Eruption

Identification of the causative drug can be difficult in LDE, as timing of the eruption can vary. The latent period has been reported to range from a few months to 1 to 2 years.¹⁵ Additionally, the clinical picture is often complicated in patients with a history of different drug dosages or multiple medications. When present, the histologic features of parakeratosis and eosinophils can be clues that a lichen planus–like eruption is drug related rather than idiopathic. However, the absence of these features does not rule out a medication or environmental trigger. In this case, the time-event relationship likely indicates that the eruption was related to the levonorgestrel-releasing IUS and not triggered by other medications or not idiopathic in nature. Lichenoid drug eruptions can resolve within a few weeks or up to 2 years after drug cessation and can occasionally be complicated by partial or complete resolution and recurrence even when the drug has not been discontinued.^16,17 Lichenoid drug eruptions or idiopathic lichen planus generally are treated with topical immunomodulators or corticosteroids.³

Based on the time-event relationship, morphology, distribution, and histopathologic findings, we conclude that our patient developed LDE in response to the placement of a levonorgestrel-releasing IUS. Clinicians should be aware of the possibility of LDE occurring as a rare adverse effect of these devices.