The annual sick season is upon us.

The first signs of fall each year inaugurate the cold and flu season — along with higher absence rates at work and school.

But studies and surveys make it clear that illness gets two-thirds of the blame for “sick” days. One-third of the reasons are all over the map.

Take the employee who couldn’t come to work because of a toe stuck in a faucet. Or the employee who was upset after watching “The Hunger Games” movie. Or the one whose hair turned orange in a home dye job.

All three were real-life examples shared Tuesday in a CareerBuilder survey in which human resource managers were asked for unusual absence excuses they’d heard.

The excuses may be funny, but business managers and productivity experts aren’t laughing.

American workers take about 2.8 million work days of unplanned absences a year, not counting planned vacation days, holidays or personal days. And that costs billions of dollars in lost productivity.

A 2010 Mercer/Marsh report on the financial effect of employee absences said the cost of unplanned time off amounted to 5.8 percent of total payroll costs.

As a percentage, that’s not a big figure. But, the report noted, “the total costs for planned absences, such as vacations and holidays, average an equivalent of 26 percent of base payroll.”

In other words, one-fourth of employers’ payroll expenses cover work time when employees aren’t at work.

That helps explain why some employers check up on workers who call in sick. According to a Harris Interactive survey taken in August and September, nearly one-third of employers who responded said they usually called the employee at home later in the day or required a doctor’s note to verify that the person was at home or was truly sick.

About one in five of the employers surveyed said they’d asked other employees to call “a suspected faker,” and about one in seven said they’d gone so far as to drive by a suspected faker’s home.

The psychological jury is out, though, as to whether faked sick days are completely bad. “Mental health days” get credence from counselors who see the toll of stressful workplaces.

According to Sean Sullivan, a co-founder of the Institute for Health and Productivity, there’s a “presenteeism” problem when workers come to work but aren’t fully functioning because of physical, emotional or other time-draining distractions.

Organizations aren’t getting value out of workers who show up but aren’t really working. So in those cases, it may not make much difference if an employee calls in sick or shows up.

Workplaces with excessive unplanned absences may need to reassess their corporate culture.

Connie Russell, a Kansas City leadership coach and counselor, said managers “need to make sure that employees understand how their work contributes to the overall good and that their contributions are valued.”

When that communication is missing, workers are more likely to not know — or not care — that it costs their organizations when they don’t show up.

“I’m also hearing that people are experiencing burnout, that it’s hard to work in environments of hyper change,” Russell said, noting another reason why otherwise good workers might take unplanned days off.

The new CareerBuilder survey found that next to being sick, the most common reason workers call in sick is because they “don’t feel like going to work.” One-third of the respondents admitted that reason.

Nearly one-third said they called in sick simply because they “felt like they needed to relax.” Other excuses included catching up on sleep or running errands.

All of those reasons are likely to be used more frequently as the year winds down. December ranks as the most popular month to call in sick.