In rare cases, people taking propylthiouracil for an overactive thyroid may develop a distinctive lacy, bluish skin pattern called livedo reticularis, which typically disappears after stopping the medication.
Claim Context
Livedo reticularis is a rare cutaneous manifestation associated with propylthiouracil-induced ANCA-positive vasculitis, occurring in some patients after months of treatment and resolving after drug discontinuation.
“With the use of PTU, alopecia areata and livedo reticularis in the lower extremities were presented in the patient... Livedo reticularis is not mentioned as a manifestation of PTU-induced ANCA-associated vasculitis in reports based on our knowledge, and this presentation in PTU-induced ANCA-associated vasculitis is infrequent.”
Evidence from Studies
No evidence studies found yet.
What Would Prove This
Per GRADE and EBM methodology, here is what ideal scientific evidence would look like to definitively prove or disprove this claim, ordered from strongest to weakest.
The pooled frequency and clinical characteristics of livedo reticularis among all reported cases of propylthiouracil-induced ANCA-positive vasculitis.
A systematic review and meta-analysis of all published case reports and series describing livedo reticularis in patients with PTU-induced ANCA vasculitis, extracting data on age, sex, time to onset, resolution after discontinuation, and coexisting symptoms, with quality assessment of each case.
The incidence rate of livedo reticularis among Graves' disease patients treated with propylthiouracil compared to those treated with methimazole.
A prospective cohort study of 5,000 Graves' disease patients on propylthiouracil and 5,000 on methimazole, with monthly dermatological exams for 24 months to detect livedo reticularis, and ANCA testing in those with skin changes.
Whether propylthiouracil exposure is more common in patients presenting with livedo reticularis and ANCA positivity than in those with livedo reticularis without ANCA or without vasculitis.
A multicenter case-control study comparing 150 patients with ANCA-positive vasculitis and livedo reticularis to 300 controls with livedo reticularis without ANCA or vasculitis, assessing prior PTU exposure, duration, and dose, with adjustment for autoimmune comorbidities.
That livedo reticularis can occur alongside ANCA-positive vasculitis in a patient taking propylthiouracil.
A detailed clinical description of a patient with Graves' disease on PTU who develops livedo reticularis, confirmed ANCA positivity, and resolution after PTU discontinuation, with skin biopsy and laboratory confirmation.