For most workplaces, you must tell your manager about any illness that is contagious, serious, affects safety, or stops you doing your job reliably, and in some sectors (like food handling) there is a specific list of illnesses and symptoms you are legally required to report.

Key illnesses and symptoms to report

In many jobs, you should report illnesses that:

  • Are contagious , such as flu‑like illnesses, stomach bugs, or COVID‑type symptoms.
  • Cause vomiting, diarrhoea, fever, or jaundice, especially if you handle food, care for people, or work closely with others.
  • Interfere with your ability to work safely (for example, severe dizziness, fainting, or loss of concentration when operating machinery or driving).

If you are a food handler, guidance says you must report symptoms such as:

  • Diarrhoea or vomiting
  • Stomach pain, nausea, or fever
  • Jaundice (yellowing of skin or eyes)
  • Close contact with someone who has a serious food‑borne infection (such as norovirus or certain types of Salmonella).

Specific serious infections (especially in food work)

Food safety rules highlight several diagnosed infections that must be reported to a manager so they can involve public health authorities where required:

  • Norovirus
  • Hepatitis A
  • Shigella
  • Shiga toxin‑producing E. coli (STEC)
  • Salmonella Typhi (typhoid fever)
  • Non‑typhoidal Salmonella.

If you are told by a doctor that you have one of these, you should not work with food until your manager and, usually, the local health authority confirm it is safe to return.

Long‑term or recurring health problems

You should also inform your manager (often via HR or occupational health) if you have:

  • A long‑term condition that causes repeated or long sickness absences.
  • Recurring short‑term absences that may add up (for example, frequent days off for the same condition).
  • A health problem that may require workplace adjustments, such as chronic pain, work‑related stress, or another ongoing medical issue.

In many organisations, managers use occupational health services to understand how to support you, adjust duties, or manage risk.

Work‑related diseases you must report (employers’ duties)

In some countries (for example the UK), employers must report certain work‑related diseases to the national safety regulator when diagnosed, such as:

  • Occupational dermatitis
  • Carpal tunnel syndrome from work‑related causes
  • Hand‑arm vibration syndrome
  • Certain occupational respiratory diseases and other specified conditions.

These are usually reported by the employer once there is a confirmed diagnosis, but you are expected to tell your manager or HR about symptoms and diagnoses that may be caused or worsened by your job.

Practical rule of thumb

As a simple guide, you should report your illness to a manager if:

  • You might pass it to colleagues, customers, patients, or the public.
  • It affects safety‑critical work (driving, operating machinery, medical care, food handling).
  • A doctor has signed you off work or diagnosed a condition that may be work related or long term.

When in doubt, it is safer to inform your manager in general terms (you do not always have to share every detail) and follow your workplace’s sickness and confidentiality policies. Information gathered from public forums or data available on the internet and portrayed here.