Now that it’s fall, your kids are getting back on the bus every morning and heading off to school. Although these days are all about learning (with a bit of fun mixed in), it’s not all good news. Being surrounded by a bunch of other kids means that your children may be more vulnerable to coming down with the sniffles — or worse. A common cold is bad enough, but parents need to watch out for some major maladies in order to keep their children safe and sound this season.

Promoting healthy habits can stave off a lot of the most worrisome illnesses. Reminding children to wash their hands frequently and to not share drinks with others can help to improve their immunity. But sharing other items — such as hats, towels, and brushes — can be bad news, too.

In a school environment, head lice can quickly spread in classrooms when children share personal belongings or keep these belongings in areas like cubbies or class closets. Lice infestations are common among young children. In fact, anywhere from 6 million to 12 million lice infestations occur among children ages three to 11 each year, according to the U.S. Centers for Disease Control and Prevention.

Of course, most schools will perform lice checks on a semi-regular basis. But parents need to do their due diligence, too. Watch for signs of head lice, which include itching, head sores, sleeping problems, and a tickling feeling on the scalp. If you suspect your child might have head lice (or their school, community center, or extracurricular facility has reported a lice outbreak), take action to have them checked and follow all healthcare provider recommendations.

Young children are particularly vulnerable to other illnesses, as well. Hand, Foot, and Mouth disease is one that primarily affects children under the age of five, which means daycare workers and preschool teachers need to be on the lookout.

This contagious viral infection actually has no treatment and will typically go away on its own; however, proper hydration is key and the disease may become serious under certain circumstances. It’s often caused by person-to-person contact with an infected individual’s saliva, blister fluid, nasal or throat discharge, or stool. Symptoms of HFMD include a suppressed appetite; sore throat; mouth sores; rash on the hands, feet, elbows, knees, buttocks, or genitals; irritability; and general feeling of unwell. Talk to your doctor if your child’s fever and other symptoms persist after a few days or if their sores/sore throat keep them from drinking liquids.

Another disease that spreads rapidly in schools and childcare settings is conjunctivitis. Also known as pinkeye, this inflammatory illness is one of the most common eye-related conditions worldwide. As such, it causes a lot of kids to miss school; an estimated 3 million school days are lost every year due to pink eye infections. Pinkeye has many possible causes and typically dissipates fairly quickly, assuming you follow your physician’s recommendations. But it can certainly be uncomfortable while it lasts, as its symptoms may include swelling, discharge, sensitivity to light, itching, burning, crustiness, blurriness, and discoloration.

While many of the most common diseases in schools and childcare may clear up quickly with no complications, there are others that need to be taken very seriously. Meningococcal meningitis is one of these diseases.

Although individuals of any age can develop this illness, the rates of development are highest in those under the age of one and those in adolescence. If left untreated, the consequences can be dire: brain damage is common and the disease can prove fatal in 50% of cases. Be sure to watch for sudden fever, neck stiffness, headache, confusion, light sensitivity, nausea, and vomiting. Even though these symptoms can occur with other conditions, their sudden onset coupled with rash and joint pain should raise alarm. It’s imperative to seek out immediate medical treatment if you suspect meningococcal meningitis in your child.

Back-to-school season can be an exciting time, but all that new contact makes this time of year rife with illnesses. Parents, educators, and other trusted adults must stay alert and take action quickly if one of these diseases presents itself in the classroom or at home.