A Case of Exertion-Induced Unilateral Facial Flushing in a 70-Year-Old Female

Case at a Glance

A 70-year-old female with a history of pulmonary embolisms and a minor stroke presented with recurrent episodes of sharply demarcated unilateral facial flushing and sweating upon physical exertion. Despite multiple consultations, her symptoms remained undiagnosed. The clinical presentation was ultimately identified as classic Harlequin syndrome.

Patient's Story

A 70-year-old female presented for evaluation of a recurring and striking phenomenon she experienced during physical activity. She reported that for the past several years, whenever she engaged in activities like gardening or strenuous housework, the left side of her face would become flushed, red, and sweaty, while the right side would remain pale and dry. The line of demarcation was sharp and followed the exact midline of her face. She and her family were concerned, but she noted that previous physicians had been dismissive of the complaint. Her significant past medical history includes recurrent pulmonary embolisms, for which she is on long-term anticoagulation with rivaroxaban, a remote history of a minor stroke with no residual deficits, and Terrien's marginal degeneration of the cornea.

Initial Assessment

Upon initial examination, the patient was comfortable and in no distress. Vitals were stable. The physical exam was unremarkable at rest, with symmetrical facial color and no neurological deficits. The patient provided a photograph taken during a recent episode, which vividly demonstrated left-sided facial erythema and apparent sweating, with contralateral pallor and anhidrosis, sharply divided at the midline. Her medication list was reviewed, confirming compliance with rivaroxaban.

The Diagnostic Journey

The patient's presentation of unilateral flushing and sweating triggered by exertion is a classic sign of autonomic dysfunction. Given her history of a stroke, a central lesion affecting the sympathetic pathways was considered, but the absence of other neurological signs or symptoms made this less likely. The pathognomonic features pointed strongly toward Harlequin syndrome, a rare autonomic disorder characterized by unilateral loss of sympathetic innervation to the face. In response to a stimulus like heat or exercise, the intact side vasodilates and sweats normally (or in a compensatory fashion), while the denervated side cannot, resulting in the dramatic 'half-red, half-white' appearance. While this can be associated with trauma, anesthesia, or compressive lesions (e.g., Pancoast tumor), it is idiopathic in over half of cases.

Final Diagnosis

Idiopathic Harlequin Syndrome.

Treatment Plan

The cornerstone of management was patient education and reassurance. The benign nature of idiopathic Harlequin syndrome was thoroughly explained to the patient and her family, which significantly alleviated their anxiety. No specific medical or surgical treatment for the syndrome itself was indicated. The treatment plan focused on the continued, careful management of her known comorbidities, including anticoagulation for pulmonary embolism prevention and regular monitoring by her ophthalmologist for Terrien's degeneration.

Outcome and Follow-up

The patient expressed great relief at finally receiving a diagnosis and understanding the cause of her symptoms. At a follow-up visit, she reported that the episodes continued to occur with exertion but were no longer a source of fear. She was advised to continue her routine follow-up with her primary care physician and specialists for her established health conditions. The prognosis for the Harlequin syndrome itself is excellent, with the condition being a cosmetic and physiological curiosity rather than a threat to her health.