With a sick kid on a school day, what’s a parent to do?

To send your snot-nosed, hacking child to school or not: That is the question. Whether ’tis nobler to miss yet another round of critical meetings, deadlines or social obligations to nurse him at home or suffer the slings and arrows of angry fellow parents . . . . Well, you get the picture.

The choice may seem obvious — it’s certainly more ethical to keep the kid home for the full length of an illness — but it’s not always respected, judging by the plethora of sniffling, sneezing, crusty-looking kids in my sons’ classrooms. We’ve all been guilty now and then, though some friends with high schoolers shift blame to their ailing offspring, who fear missing a day of classes lest they fall behind on their work.

“It can be hard to know what to do,” sympathizes Linda Davis-Alldritt, president of the National Association of School Nurses. She acknowledges that factors such as whether parents have sick leave or emergency child-care options often play a huge role. For one thing, the average kid falls ill a lot — with an estimated two to six bouts of the common cold alone every year — but is often well enough to head off on the bus anyway. “If you tried to keep every kid home till they’re not coughing anymore, there’d be so much missed school they wouldn’t get much of an education; the same with runny noses,” says Ivor Horn, a mother of two who works as a pediatrician at Children’s National Medical Center.

Still, it’s important to try to balance school attendance with making sure that an ill child gets the care, rest and attention he needs to recuperate. And then there’s the broader obligation to prevent the spread of communicable illnesses.

“Kids are going to get colds and viruses and we can’t panic, but you can try to do the right thing for your child, and for the larger community,” says Horn. Many schools have policies that lay out when you should, or shouldn’t, send your kid to class.

Here are some other pointers:

_Fever. While there is no definitive answer on what constitutes a worrisome fever, Horn says that she starts to get concerned when a child’s temperature reaches 100 degrees and that she keeps her own elementary-aged children home when it reaches 101 or higher. And don’t jump the gun as soon as the patient appears to rebound: Youngsters should be fever-free without any medication for at least 24 hours before they return to school. Giving your kid some acetaminophen to lower a fever and sending him off to school is not right for the child — or his classmates.

_Vomiting and diarrhea. Kids should be kept home for the duration of gastrointestinal illnesses, and for at least an additional 24 hours, says Davis-Alldritt.

_Cold symptoms. Typically, it’s okay to send your child off to school with a mild sore throat, a cough or a stuffy or runny nose — even if that snot is a shocking shade of green. “Parents freak out about colored mucus, but the truth is that it’s usually just part of the process when you have a viral infection or cold” and really doesn’t have anything to do with how contagious you are, explains Horn. But if a child can’t control a cough or it’s accompanied by phlegm, some extra rest or a call or visit to the doctor is probably in order before returning to school, says Davis-Alldritt.

_Energy level. The decision about staying home often comes down to whether a kid is well enough to concentrate and participate at school. “If your child has been up and not feeling well all night, really, how productive are they going to be in class?” says Horn. “But if they were feeling ill and still have a little bit of a runny nose but now feel better and are back to running around, you can definitely consider sending them to school.”

_Rashes, pinkeye, earaches. These should be checked out by a doctor and dealt with before a child goes to school.

And how about older kids who claim to be nauseated but look just fine, or who have frequent, vague symptoms, such as a headache every Monday morning?

Davis-Alldritt stresses that parents should always be on the lookout for school avoidance: “About 30 percent of children who come through a school nurse’s door are there for stress or other mental health issues,” she says.

“There are lots of reasons that kids say they’re sick,” agrees Horn, who cites bullying, other social problems and test anxiety as examples. “Sometimes teenagers are really, really busy; they have too much going on and they need a pause, and it’s your parental right to allow them to take that break.”

Overall, deciding what to do is about knowing your children. “I tell parents to trust themselves on both ends of the spectrum — when you feel like something is just not right as well as when you feel like ‘my kid is fine today,’ ” says Horn.

And if you’re in that iffy stage where you think they’re well enough to hit first-period Biology but you’re not 100 percent positive, she recommends giving teachers or the school nurse a heads-up: “What that does is set up a good relationship with the school, so they don’t think you’re trying to put something over on them,” she says. (This is seconded by a teacher friend of mine, who chastises: “You’re not fooling anyone. We always know when a kid shouldn’t be here.”) And before sending them off, be sure to remind them of good hygiene habits, such as coughing into the crook of the elbow, using tissues when necessary and copious hand washing.

Also, bear in mind that not every parent is going to get it right every time, says Davis-Alldritt, a mom to three boys of her own. “Even as a nurse I made the wrong call, every now and then, and said, ‘I don’t see anything going on with you today’ — and then I’d get the call to come get them,” she says.

So from now on, I promise not to second-guess that parent who sends her son or daughter to school with a wildly contagious stomach virus if you’ll cut me some slack the next time I miss a case of strep.