Cutaneous ultrastructural changes and photosensitivity associated with amiodarone therapy

Area of Science:

• Dermatology
• Pharmacology
• Pathology

Background:

• Amiodarone, an antiarrhythmic medication, is recognized for causing photosensitivity and skin hyperpigmentation.
• Cutaneous side effects necessitate further investigation into their underlying mechanisms.

Purpose of the Study:

• To investigate the ultrastructural changes in the skin of patients using amiodarone.
• To correlate these findings with clinical photosensitivity and sun exposure.

Main Methods:

• Skin biopsies from sun-exposed and non-sun-exposed sites of five amiodarone users were analyzed.
• Histopathological examination included light microscopy, electron microscopy, and direct immunofluorescence.
• Phototesting was performed on six patients.

Main Results:

• Light microscopy was not diagnostic; however, electron microscopy revealed distinctive intracytoplasmic inclusions in various cell types.
• These inclusions are identified as phospholipid membranes, indicative of amiodarone-induced lipidosis, not previously reported lipofuscin.
• Inclusions were more prominent in sun-exposed skin, suggesting sun exposure accelerates their formation.
• Four of five patients exhibited photosensitivity symptoms; phototesting showed reactions to UVA and UVB in three patients, correlating with longer amiodarone use.

Conclusions:

• Amiodarone induces characteristic intracellular lipidosis, visualized as phospholipid membrane inclusions via electron microscopy.
• Sun exposure appears to exacerbate the accumulation of these amiodarone-related deposits.
• Photosensitivity reactions to UVA/UVB are common in patients on long-term amiodarone therapy.