Republican presidential nominee Donald Trump's nose became the target of critics, late-night comedians and snarky Twitter users, during his first presidential debate against Hillary Clinton.

Trump could be heard sniffing sharply on several occasions, prompting a few eagle-eyed (or bat-eared) viewers to create supercut videos of all his sniffles. One 46-second video shows Trump sniffing dozens of times during the debate.

And while some have chalked it up to sensitive microphone or allergies, others even suggested it might be an indicator of alleged drug use -- including , the former governor of Vermont.

In a statement to the , the Trump campaign hit back at Dean.

鈥淕overnor Dean鈥檚 comment was beyond the pale and has no place in our important political discussion," it said. "On a night where millions of Americans were able to compare and contrast the policies of both candidates, Governor Dean went straight to the gutter and was nothing more than a sad distraction in a desperate attempt to stay relevant.鈥�

But Dean's allegation caught on quickly in the Twitter-verse.

Trump's sniffles also spawned at least one parody account on Twitter.

Some suggested the sniff was simply a sign of nerves, with one user comparing the situation to the first televised presidential debate in 1960, between Richard Nixon and John F. Kennedy. Nixon could be seen sweating during that debate 鈥� which some interpreted at the time as Nixon feeling in over his head against the more charismatic Kennedy.

Others saw Trump's sniffling as karmic payback for his response to Clinton's pneumonia trouble earlier this month. Trump suggested that Clinton was not physically fit to be president, after she collapsed at a ceremony honouring the victims of the Sept. 11, 2001 attacks.

Trump told CNN on Tuesday morning that he does not have a cold or seasonal allergies, and that the microphone was "very bad but maybe it was good enough to hear breathing."