A case of undiagnosed harlequin syndrome presenting in general dental practice

Arlecchino (Harlequin) was a theatre character in 16th century Venice whose costume consisted of a grotesque mask, named a Harlequin mask (Figure 1). The initial masks were grotesque but were later refined with diamond-shaped colourful patterns, or blackening of one half of the face. Lance et al 1988 observed five patients who presented with unilateral diminished sweating and flushing of the facial skin in response to heat, exercise or stress.¹ The unilateral mid-facial demarcation of the contralateral erythematous flushed skin contrasting with the ipsilateral non-flushed side was reminiscent of this mask, hence leading to the designation of the term Harlequin syndrome.²

A 45-year-old female presented to her general dental practitioner for routine dental care. She had rushed to the appointment and presented to her dentist with distinctly demarcated unilateral facial flushing and sweating. The dentist enquired further about this appearance with the patient reporting a one-year history of unilateral diminished sweating and flushing of the left facial skin in response to exercise. As the dentist considered this to be unusual, he organized a referral to the local oral medicine department.