Is My Child Too Ill for School? The Complete NHS Guide

My School Agent | 8 July 2026

It was 7:15am. My daughter had a slight temperature. Not burning up, just warmish. She said her tummy felt funny. But she also had a spelling test she'd revised for all week.

I had three client calls starting at 9am. I stood in the hallway holding a thermometer, doing mental arithmetic on childcare logistics, wondering if I was a terrible parent either way.

Every parent has been here. The morning-of-school illness limbo. Too unwell to learn, or just trying it on? Genuine sickness, or exam nerves?

The NHS has guidance. It's more helpful than you'd think.

The "Well Enough to Learn" Test

The NHS uses one simple question: is your child well enough to take part in lessons and activities?

Not "are they symptom-free." Not "are they 100% fine." Can they sit upright, concentrate, and not infect everyone around them?

If yes, send them in. If no, keep them home.

This is harder than it sounds. A snotty nose and a cough? Probably fine. A snotty nose, a cough, and they slept three hours last night? Different story.

The NHS List of 18 Conditions

The NHS publishes guidance on when children should stay off school for specific illnesses. Here are the headlines.

Keep Them Home

  • Chickenpox: Until all spots have crusted over (usually 5 days after they first appeared)
  • Impetigo: Until lesions are crusted over or 48 hours after antibiotics started
  • Measles: 4 days from onset of rash
  • Scarlet fever: 24 hours after starting antibiotics
  • Whooping cough: 48 hours after antibiotics, or 21 days from onset if no antibiotics
  • Vomiting and diarrhoea: 48 hours after last episode

They Can Go In

  • Conjunctivitis: No exclusion needed (most parents assume otherwise)
  • Head lice: No exclusion needed
  • Threadworms: No exclusion needed
  • Cold sores: No exclusion needed
  • Hand, foot and mouth: No exclusion needed if they feel well
  • Slapped cheek (fifth disease): No exclusion once rash appears (they're only contagious before the rash)

The Grey Area

  • Coughs and colds: Send them in unless they're too unwell to learn
  • Sore throat: Send them in unless it's strep throat or scarlet fever (high fever, difficulty swallowing, swollen glands)
  • High temperature: Keep home if it's 38°C or higher. They can return once it's gone and they feel well.

What About Antibiotics?

Some parents think children must finish a full course of antibiotics before returning to school. Not true.

For most bacterial infections, children can return 24 to 48 hours after starting antibiotics, as long as they feel well enough.

Check the specific NHS guidance for the illness. Scarlet fever and impetigo both require 24 hours on antibiotics. Whooping cough needs 48 hours.

Calling the School

Most schools want you to call before 9am on the first day of absence. Text or email doesn't always count. Check your school's policy.

You don't need to give a detailed medical history. "She has a temperature and is too unwell to attend" is enough.

If your child is off for more than a few days, the school may ask for a doctor's note. This depends on their attendance policy.

What Happens to Their Attendance Record?

Genuine illness is recorded as an authorised absence. It doesn't count against your child, and you won't be fined.

Schools track attendance carefully. If your child's absence rate is unusually high, the school may ask to meet with you. This isn't punitive. They're checking if there's an underlying health issue or if you need support.

Persistent absence (missing 10% or more of school) triggers additional monitoring. Again, genuine illness is fine. They're looking for patterns of unauthorised absence.

The Morning-Of Decision

You won't always get it right. Sometimes you'll send them in and the school will ring at 10:30 asking you to collect them. Sometimes you'll keep them home and they'll be bouncing off the walls by lunchtime.

Trust your instincts. Use the "well enough to learn" test. Check the NHS guidance. Make the call.

I built My School Agent partly to reduce the mental load of these decisions. It won't tell you whether your child is too ill for school. But it will handle the fourteen other things on your plate that morning, so you can focus on the one that matters.

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