If your infant is 2 months or younger and has a rectal temperature of 100.4 degrees F. or higher, he could be sicker than he seems. (One exception to this rule is if your 2-month-old just got his vaccinations and runs a low-grade fever within 36 hours.) Young babies usually don't show a lot of symptoms, but they can quickly develop a serious bacterial infection because their immune system is still immature, says Sue Hubbard, MD, a pediatrician in Dallas. Parents often assume their baby just has a cold, but colds usually don't cause a fever at this age. A doctor will see an infant with a fever as soon as possible, but if it's the middle of the night, your pediatrician may send you to the ER.
When your child starts to cough so hard that she's wheezing or simply can't stop, she's probably having an asthma attack and will need medication to treat it. "A viral illness can cause asthmatic symptoms in any child, even if it's just for a short time," says Mary Ellen Renna, MD, a pediatrician in Woodbury, New York. Of course, if your child has already been diagnosed with asthma, you'll have an inhaler or a nebulizer at home. "But you should call the doctor if she's used her rescue medication and her coughing hasn't lightened up within 20 to 30 minutes," says Dr. Renna.
If your child wakes up during the night with a cough that sounds like a seal barking, she has croup, an illness you can usually treat yourself. Take her into the bathroom, turn on a hot shower, and sit together in the steam. If she's still barking, cool air can help, so take her outside on a chilly night -- or even stand in front of your freezer with the door open. Chances are, one of these steps will ease her coughing, but you should call the doctor immediately if she looks like she's struggling to breathe (her ribs are pulling in and out with each breath, her nose is flaring, or she's grunting when she tries to take in air). "These are signs of respiratory distress, and the doctor may tell you to go to the hospital," says Dr. Renna. If she's coughing so hard that she's turning blue, call 911.
If your child develops a rash that looks like tiny red magic-marker dots, and he also has a fever, he could have a serious bacterial infection such as meningitis. These dots, called petechiae, remain colored even when you press down on them. (Other rashes tend to become pale for a moment when you push on them, and then the color rushes back.) A child can also get petechiae (without a fever) after he coughs a lot or vomits, or if he strains when going to the bathroom. In those cases, the rash is probably caused by broken capillaries, but you should call the doctor in the morning.
If your child throws up repeatedly -- even when there's nothing left to come up -- it could be caused by anything from food poisoning to twisted intestines. Call the doctor right away if your child vomits any blood or she's throwing up and seems disoriented. It's also an emergency if your baby has projectile vomit that is greenish-yellow; this could be a symptom of pyloric stenosis, a congenital abnormality that requires surgery.
If your child can't stand on one leg and has a sudden fever, he could have a serious infection inside his knee or hip joint. "He needs to be evaluated quickly because the infection could destroy the joint if it isn't treated with IV antibiotics within 48 hours," says Lewis Krata, MD, a pediatrician at Saint Vincent's Catholic Medical Center in New York City. "The typical scenario is for a child to act a little sick one day and the next day have a high fever and severe pain in a single joint."
If your child really can't move his wrist, leg, or shoulder, he may have fractured it. Call right away to see whether your doctor wants you to go to the ER for x-rays. It's especially important to see a doctor soon if your child is under age 2.
If your child hits her head and gets knocked unconscious, you'll call 911 immediately, and then your doctor. But when she just cries after falling, you might not know whether to worry or not. If she vomits more than once, seems sleepy or disoriented, or has any clear fluid draining from her nose or ear, phone the doctor right away, says Dr. Renna. You should also closely examine your child's head: Although a big lump on her forehead looks scary, it's actually more serious if she bangs the sides of her head. If her skull looks slightly dented, that could be a sign of a fracture.
If your baby's poop looks like grape or currant jelly, he could have a serious condition called intussusception, in which a baby's bowel gets kinked and obstructed. Bloody diarrhea, on the other hand, could indicate food poisoning or bacterial gastroenteritis, and your doctor will want to test for a variety of possible bacterial and parasitic infections.
It's common for a child's eye to swell up from a bug bite or poison ivy, but if your child also has a fever, he may have orbital cellulitis, a serious sinus infection that extends into the part of his skull in which the eye rests, says Parents advisor Ari Brown, MD, author of Baby 411. You'll first notice that your child's eyelid is red and swollen, but within several hours, his entire eye will start bulging and he'll have trouble moving it. He should be treated immediately with IV antibiotics and will need to be hospitalized.
If the pain gets worse when your child jumps up and down or even when she just moves around in bed, it could be appendicitis. "When there's an infection in the appendix, the tissue over a child's belly gets inflamed," says Dr. Renna. "Moving or jumping causes her belly to rub against the tissue and causes more pain." With appendicitis, the pain often starts around the belly button and then settles in the lower right quadrant.
If you're holding your child's hand and she pulls one way while you pull the other, you can dislocate her elbow -- a painful condition called nursemaid's elbow. Her arm will hang limp, and she'll refuse to move it. This is most common in toddlers, but it can happen in kids up to age 6. Your pediatrician can manipulate your kid's elbow back into position, but it's crucial that you call right away before her elbow gets swollen.
In these situations, you can let your pediatrician sleep through the night.
Fever in a child who's 3 or older
Fever is not a disease, it's a symptom -- and contrary to what some people have heard, it won't cause brain damage. "If your older child has a temperature of 104 degrees F., that doesn't mean he's any sicker than if it's 102 degrees F.," says Dr. Sue Hubbard. Only call if your child is very lethargic -- he won't give you a smile or even watch his favorite video.
A little blood in poop
If your child's been constipated, he can get a small anal tear that bleeds. This is also common in babies who've just started solids, says Dr. Brown.
Goopy or crusty eyes
Pinkeye is particularly common when your child has a cold. Make an appointment for the next day, says Dr. Brown. Kids under the age of 2 may also get crusty eyes when they have an ear infection, but it's still okay to wait until the morning to call the doctor.
An itchy rash
It could be hives (which looks like raised mosquito bites with flat red circles around them), eczema (red and scaly), or contact dermatitis (red blisters in a streak or a patch).
Originally published in Parents magazine.
All content, including medical opinion and any other health-related information, is for informational purposes only and should not be considered to be a specific diagnosis or treatment plan for any individual situation. Use of this site and the information contained herein does not create a doctor-patient relationship. Always seek the direct advice of your own doctor in connection with any questions or issues you may have regarding your own health or the health of others.