Day three. The throat still hurts, there is no rash, and dinner went back to the kitchen almost untouched. The question is not whether this is serious. It is narrower: wait one more day, or book an appointment and ask for a swab?

Quick reference

QuestionShort answer
Can strep happen without a high fever?Yes. RKI describes a range from mild soreness to high fever
Does a cough argue for or against strep?Against. CDC lists cough, runny nose, hoarseness and pink eye as viral signs
From what age is a test worth doing?RKI advises testing mainly in children older than 3
What if the rapid test is negative?In symptomatic children aged 3 and over it is backed up with a culture
How long off school after antibiotics?UK guidance and RKI: 24 hours from the first dose, symptoms settling
Should the whole family be swabbed?Not for an uncomplicated case; RKI advises no special measures for contacts
How long does a viral sore throat last?NHS: usually better on its own within a week

What actually separates viral from strep

Start with the number that reframes the whole decision. The American Academy of Pediatrics puts it plainly: only 20% to 30% of throat infections in school-age children are caused by strep (HealthyChildren, AAP). The rest are viruses, and viruses do not answer to antibiotics.

The NHS says the same thing from the other end. Sore throats are usually caused by viruses, very occasionally by bacteria, and they normally get better by themselves within a week (NHS). For tonsillitis specifically, the NHS notes that most children and adults get the viral kind, which clears up on its own (NHS, tonsillitis).

Now the honest part, the one that saves a lot of squinting into a torch-lit mouth. Appearance alone does not settle it. The Robert Koch Institute describes strep throat as running the full range, from mild soreness with an almost unremarkable examination all the way to high fever, severe pain, a swollen red pharynx and purulent exudate (RKI). A mild throat does not rule strep out, and an angry-looking one does not prove it.

What does help is the company the sore throat keeps. The CDC is specific: cough, runny nose, hoarseness and conjunctivitis suggest a virus rather than strep (CDC). The AAP agrees that most sore throats are viral, especially when a runny nose or cough is part of the picture (HealthyChildren).

So the useful question at the kitchen table is not "how red is it". It is: is anything else going on that belongs to a virus?

Age changes the odds more than anything else

This is the part that quietly saves the most unnecessary appointments.

Strep throat is most common between the ages of 5 and 15. The AAP calls it extremely uncommon in infants and toddlers, and the CDC describes it as rare in children younger than three. The RKI turns that into a practical rule: testing for group A strep is generally recommended for children over three who have a sore throat, markedly swollen neck lymph nodes and fever, and not for children under three, nor for anyone whose picture is dominated by viral signs such as a runny nose, hoarseness, cough or mouth ulcers.

For the two-year-old who has been mourning her soup since Tuesday, a virus is by far the better bet. Why that age catches so many of them in a single winter is a separate story, told in why kids get sick so often at daycare.

What a swab and a rapid test can and cannot tell you

A rapid test is an antigen test done on the swab tip, with an answer in minutes. A classic swab goes to a lab for culture, and the answer takes a day or two.

The RKI compares them precisely: the available rapid antigen tests are highly specific but not equally sensitive. In parent language, a positive result is trustworthy and treatment follows, while a negative result does not close the file. Where the rapid test is negative or unclear, the RKI points to culture or a molecular test on a throat swab. The CDC says the same for children older than three: follow a negative rapid test with a throat culture (CDC clinical guidance).

There is also a limit no test crosses on its own. The RKI notes that a large share of people are colonized by this bacterium without any symptoms, and that in the colder months this particularly applies to children. That is part of why guidance steers away from testing a child with an obviously viral picture: a positive swab in that child does not prove strep is causing this particular sore throat.

When testing is worth it, and when it is not

Testing earns its place when several things line up. The child is over three. The sore throat came on suddenly and hurts a lot. There is fever. The neck glands are swollen and tender. And there is no cough, runny nose or hoarseness.

Testing usually does not earn its place when the child is coughing and dripping, when the child is under three, or when the sore throat is mild and already fading.

The clinician decides who gets tested, which medicine is used and at what dose. The reverse holds too, and the AAP states it flatly: if strep is not diagnosed with a test, antibiotics should not be given. If you do go in, bring the start date, the fever pattern and how much your child has been drinking. Putting that together in two minutes is covered in how to prepare for a pediatric visit with your child's data.

Going back to daycare or school after antibiotics

Numbers here come from different countries, so keep them attributed.

UK guidance is the shortest version: stay away from nursery, school or work for 24 hours after starting antibiotics, to stop the infection spreading (NHS, Strep A).

German rules ask for the same 24 hours plus one more condition. The RKI readmission table for scarlet fever and other Streptococcus pyogenes infections states that return is possible 24 hours after the start of effective antibiotic therapy and once symptoms have settled; if symptoms persist under treatment, only after they resolve. Without antibiotic therapy, return is advised no earlier than 24 hours after the specific symptoms have settled (RKI readmission table).

Why 24 hours at all? The RKI notes that an untreated acute strep infection can stay contagious for up to three weeks, while for throat infections infectiousness ends 24 hours after effective treatment begins. The CDC frames the same idea slightly differently, saying that treatment with an appropriate antibiotic for 12 hours or longer limits a person's ability to pass the bacteria on. Your own daycare or school may set the bar somewhere in that range, so ask them and your clinician on the same day.

If the cough is the part that will not quit, when to monitor a fever and cough and when to call the doctor covers the follow-on days.

Does the rest of the household need testing?

Short answer: not routinely.

For contacts of an uncomplicated case, the RKI advises that no special measures are needed. Household members should simply know the risk and the symptoms, so they see a doctor promptly if they fall ill themselves. You test the person with symptoms, not the address.

Adults are not exempt from catching it. The CDC notes that parents of school-age children, and adults who are often around children, are at increased risk, and that crowded settings such as daycare centers and schools raise the risk of any group A strep infection. If your own throat starts burning three days later, that is your appointment to make, not a reason to swab a sibling who feels fine.

If a rash shows up

A rash changes the picture, and it is where this article hands over. A fine sandpapery rash, a strawberry tongue and pallor around the mouth point to scarlet fever, which is the same bacterium plus a toxin. What to expect, how it is treated and how long it stays contagious are covered in the separate piece on scarlet fever in children.

How KidyGrow helps you

The swab decision usually comes down to two things that are the easiest to lose: which day of the illness this actually is, and whether the line is going up or down.

In KidyGrow you note the sore throat, the temperature and roughly how much your child drank, in a few seconds, usually while the kettle boils. The app remembers the start date, so you are not counting backwards from memory in the waiting room. On day one the Daily Brief only tells you the obvious, that this is day two and that fluids are down on a normal day. Day one does not need more than that.

A week or two in, it changes character. The app learns the rhythm of your particular child and connects notes that mean nothing on their own: that the fever climbs in the evening every time, that the two skipped meals followed the worst throat day, that this is the third sore throat since September and the previous two faded by day five without antibiotics.

That last one matters more than it sounds. It is the difference between telling a clinician "she gets sick a lot" and handing over three dated episodes. The app does not diagnose and it does not spot illnesses. It puts your own notes in an order somebody can read in half a minute.

There is a smaller use for it afterwards. If antibiotics are prescribed, you log the day and hour of the first dose, and the daycare question turns into checking a timestamp instead of arguing with your own memory on a Sunday night.

Some weeks there is nothing to conclude. When half the group is ill and everything overlaps, it says so rather than inventing a pattern.

It will not tell you whether to get the swab. It will tell you this is day five of the sore throat, when the last fever was, and whether your child is drinking less than usual. The decision is the doctor's.

Frequently asked questions

Can a child have strep without a fever?

It is possible, though less typical. The RKI describes strep throat symptoms as ranging from mild soreness with an almost unremarkable examination to high fever and severe pain. That is exactly why the decision is not made on one symptom, but on the whole picture plus age, and confirmed with a test.

Should the whole family be swabbed if one child tests positive?

Not routinely. For contacts of an uncomplicated case the RKI states that no special measures are required, beyond making sure household members know the symptoms and see a doctor if they become ill. Testing follows symptoms, not shared bathrooms.

How soon after starting antibiotics can my child go back to school?

UK guidance asks for 24 hours away after the first dose. The RKI requires 24 hours after effective therapy starts and the symptoms to have settled. The CDC notes that 12 hours or more of an appropriate antibiotic already limits transmission. Your daycare or school may apply its own version, so confirm with them.

Can I tell a viral sore throat from strep at home?

Not for certain, and that is the honest answer. What helps are the viral companions: the CDC lists cough, runny nose, hoarseness and conjunctivitis as pointing to a virus. Their presence makes strep less likely, but only a test confirms it either way.

What if the rapid test is negative and my child still has a fever?

A negative antigen test does not close the question, because these tests are not as sensitive as they are specific. Both the RKI and the CDC direct clinicians to back up a negative rapid test in children with a throat culture. Until the result comes back, keep watching and go back to the practice if things get worse.

Sources

  1. NHS: Sore throat (accessed 2026).
  2. NHS: Tonsillitis (accessed 2026).
  3. NHS: Strep A (accessed 2026).
  4. CDC: Strep throat (accessed 2026).
  5. CDC: Clinical guidance for group A streptococcal pharyngitis (accessed 2026).
  6. AAP, HealthyChildren: When is a sore throat a more serious infection? (accessed 2026).
  7. RKI guide: Streptococcus pyogenes infections (accessed 2026).
  8. RKI: Readmission to community facilities under section 34 IfSG (accessed 2026).

_This article is informational and does not replace an examination by a doctor._