Black thyroid in a dog on long-term doxycycline therapy
Sarah J Stark1, Alexandra R Armstrong1, Joshua L Merickel1
1Veterinary Clinical Sciences Department, College of Veterinary Medicine, University of Minnesota, Saint Paul, Minnesota, USA.
Veterinary Surgery : VS
|October 13, 2025
Summary
Black thyroid in dogs, a condition linked to doxycycline therapy, presents as pigment within thyroid cells. This case report highlights that this benign finding does not necessitate thyroid removal in dogs.
Area of Science:
- Veterinary Pathology
- Canine Medicine
- Pharmacology
Background:
- Black thyroid is a documented condition in humans on minocycline therapy.
- This pigmentation has rarely been reported in animals.
- This is the first reported case of black thyroid in a dog associated with doxycycline therapy.
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