Osimertinib‑induced erythromelalgia: A case report.

Area of Science:

• Oncology
• Dermatology
• Pharmacology

Background:

• Osimertinib is a third-generation epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor used for metastatic lung adenocarcinoma.
• EGFR inhibitors are known to cause various cutaneous adverse events.
• Erythromelalgia is a condition characterized by redness, warmth, and pain, typically in the extremities.

Observation:

• A 77-year-old female patient with recurrent lung adenocarcinoma developed symptoms of erythromelalgia during osimertinib therapy.
• The patient presented with painful, symmetrical erythema and warmth in the distal phalanges of both hands, exacerbated by heat and relieved by cold.
• Primary erythromelalgia and other secondary causes were excluded through clinical evaluation and investigations.

Findings:

• The clinical presentation and exclusion of other causes strongly implicated osimertinib as the causative agent for erythromelalgia.
• This case represents a potential first report of osimertinib-induced erythromelalgia.
• The adverse event highlights a previously undocumented side effect of this EGFR inhibitor.

Implications:

• Clinicians should be aware of erythromelalgia as a potential adverse event associated with osimertinib treatment.
• Early recognition and management of osimertinib-induced erythromelalgia can improve patient care and treatment adherence.
• This case contributes to the understanding of the dermatological toxicities of EGFR inhibitors.