Headache attributed to aeroplane travel and reversible cerebral vasoconstriction syndrome

We are grateful to Dr. Mainardi and colleagues for their comments about our article (1). We agree that the typical clinical features of headache attributed to aeroplane travel (airplane headache (AH)) and those of reversible cerebral vasoconstriction syndrome (RCVS) are different, and typical cases of AH are not due to RCVS. As they point out, the first episode of headache during airplane travel cannot be classified as AH (2); similar to migraine, the diagnosis requires multiple episodes of headache with specific characteristics. Magnetic resonance angiography is not used for routine examination of every AH patient; however, the first headache during airplane travel sometimes requires neuroimaging evaluation to rule out secondary headache, especially for patients in whom the first headache persists, as in our case, or when there are neurologic findings associated with the headache.

RCVS is generally considered a monophasic disease, which has a limited period of three months (3) and according to the International Headache Society, no new significant headache occurs after one month following RCVS onset (2). However, regarding headache recurrence after remission of RCVS, a recent follow-up study showed that 18/168 (10.7%) RCVS patients manifested a new, thunderclap-like headache and 9/168 (5.4%) were confirmed to have recurrent RCVS by neuroimaging that occurred between six months and seven years after the initial bout (4). The authors speculated that patients with RCVS might have a higher susceptibility to this disease, and the incidence of RCVS recurrence might be somewhat higher than estimated. Patients with RCVS typically report at least one trigger (3). If airplane travel (especially at landing) is a possible trigger of RCVS as in our case, the possibility that RCVS recurs at multiple flight conditions cannot be excluded. Because our patient declared that she would never attempt air travel again, flight-dependent RCVS recurrence may not occur in future.

Again, RCVS as a potential cause of AH should be suspected in cases of headache arising several days after the resolution of the triggering factors (such as airplane descent). A previous report described some AH cases that had prolonged headache lasting for hours or days (5). Therefore, we believe that some cases of RCVS during airplane travel might be overlooked in the clinical setting, and physicians should be aware that airplane travel might be a trigger of RCVS.