MON-441 Thyroiditis After Botox Injection to the Neck: A Case of Thyrotoxicosis Triggered by Aesthetic Treatment

Abstract Disclosure: P. Roque: None. M. Lopez: None. T. Sanchez: None. M. Albano: None. P. Aquino: None. A. Lo: None. INTRO: Subacute thyroiditis resulting from locally injected Botox to the neck muscles is a rare complication from a seemingly straightforward aesthetic procedure. CASE: A 37-year-old female without prior thyroid disease presented with a 2-week history of palpitations, tremors, heat intolerance, and cold sweats following a noninvasive platysmaplasty via Botox injections. She had previously undergone said procedure without complications, however, her most recent treatment triggered said conditions. On examination, she was clinically thyrotoxic with direct tenderness over the thyroid gland. Initial tests were consistent with hyperthyroidism: TSH <0.07, FT4 2.3 and FT3 7.0, with ESR levels of 70 and negative TPO, TSI, and TRab receptor antibodies. Low uptake on RAI scan confirmed thyroiditis. She was prescribed NSAIDs and atenolol, and started on a 5-week tapering course of prednisone, leading to resolution of symptoms and normalization of thyroid tests. DISCUSSION: Subacute thyroiditis can be due to radiation, trauma, or infections; this case describes a rare instance of subacute thyroiditis following Botox injection into the platysmal bands. There is limited literature on the direct and indirect effects of Botox on the thyroid. Botox has been reported to trigger an autoimmune response in patients with underlying Hashimoto’s disease possibly from molecular mimicry. A study by Gregoric et al. found that eyelid injections of Botox on a Hashimoto patient caused persistent TSH elevation despite adequate levothyroxine therapy, likely due to anti-Botox antibodies inducing anti-TSH-R antibodies inhibiting TSH-R signaling. In this particular case, her lack of autoantibodies and unremarkable thyroid history argue against an autoimmune condition. The patient's favorable response to prednisone further supports the inflammatory nature of the thyroid dysfunction. Localized injections near the thyroid can lead to thyroid dysfunction through inadvertent thyroid manipulation or spillage of Botox into surrounding tissues, possibly causing an inflammatory response. In this case, absence of other triggers supports Botox as the primary cause of the thyroiditis. CONCLUSION: Botox injections to the cervical area used for both aesthetic and medical purposes are generally considered benign, however, can rarely trigger a severe thyroiditis reaction. Patients should be informed of said risk and monitor for possible symptoms of thyrotoxicosis. Early recognition of subacute thyroiditis allows for prompt diagnosis and appropriate management.Reference: Gregoric E, Gregoric JA, Guarneri F, Benvenga S. Injections of Clostridium botulinum neurotoxin A may cause thyroid complications in predisposed persons based on molecular mimicry with thyroid autoantigens. Endocrine. 2011 Feb;39(1):41-7. doi: 10.1007/s12020-010-9410-9. PMID: 21061092 Presentation: Monday, July 14, 2025