Harlequin syndrome can present simultaneously with ipsilateral Horner, Adie, and Ross syndromes.8 There are varying clinical presentations of Horner syndrome. Some patients with HS show autonomic ocular signs, such as miosis and ptosis, exhibiting Horner syndrome as an additional feature.5 Adie syndrome is characterized by tonic pupils with hyporeflexia and is unilateral in most cases. Ross syndrome is similar to Adie syndrome—including tonic pupils with hyporeflexia—in addition to a finding of segmental anhidrosis; it is bilateral in most cases.4
In some cases, Horner syndrome and HS originate from unilateral pharmaceutical sympathetic denervation (ie, as a consequence of paravertebral spread of local anesthetic to ipsilateral stellate ganglion).9 Facial nonflushing areas in HS typically are identical with anhidrotic areas10; Horner syndrome often is ipsilateral to the affected sympathetic region.11
Our patient exhibited secondary HS from a tumor effect; however, an underlying tumor or infarct is absent in many cases. In primary (idiopathic) cases of HS, treatment is not recommended because the syndrome is benign.10,11
If symptoms of HS cause notable social embarrassment, contralateral sympathectomy can be considered.5,12 Repeated stellate ganglion block with a local anesthetic could be a less invasive treatment option.13 When considered on a case-by-case-basis, botulinum toxin type A has been effective as a treatment of compensatory hyperhidrosis on the unaffected side.14
In cases of secondary HS, surgical removal of the lesion may alleviate symptoms, though thoracotomy in our patient to remove the schwannoma did not alleviate anhidrosis. The Table lists treatment options for primary and secondary HS.4,5,11
