Levothyroxine Induced Eczematiform Skin Eruption and Generalized Pruritus: a Case Report

Potential cutaneous hypersensitivity reaction to an inactive ingredient of thyroid hormone supplements in a dog

“…In that case the dog apparently suffered an idiosyncratic reaction to one of the inactive ingredients of the thyroid supplement rather than the hormone itself. Despite numerous discussions of such a reaction on professional medical sites, the human literature contains a limited number of published cases . Interestingly, most human cases appear to be “immediate” reactions (i.e.…”

“…Adult‐onset canine hypothyroidism is an immune‐mediated disease for which some genetic predispositions, including MHC II, have been suggested . Reported cases of allergic reactions to thyroid supplements in human medicine have included no, or limited, investigations of the specific target ingredient or its exact pathogenesis …”

“…Unfortunately, skin biopsy findings were not available for this case. Most of the few cases of thyroid hormone allergy in humans also had cutaneous clinical signs, but the liver was targeted in one of them …”

Levothyroxine-associated lichenoid drug eruption: A case report and review of levothyroxine-induced adverse reactions

“…In cases of adverse skin reactions, patch tests were all positive, suggesting the involvement of delayed type hypersensitivity (DTH). [3][4][5] As a biological substance, levothyroxine cannot be recognized by the immune system as antigen. Nevertheless, lymphocytes of patients who had taken levothyroxine were indeed sensitized to the drug.…”

“…Only a few skin lesions have been reported to be induced by levothyroxine as consequences of anaphylactic reactions, including pruritic rashes, eczematiform skin eruptions, and lichenoid eruptions. [3][4][5] Cutaneous lichenoid or lichen-planus-like eruptions may be induced by ingestion, contact or inhalation of a variety of drugs and chemicals. It is similar to lichen planus clinically and pathologically, with purple-red papules, obvious scales and eczematous change.…”