Cold, flu and hayfever are three of the most common reasons people visit a pharmacy in the UK. They can feel remarkably similar — but they’re caused by entirely different things, affect the body differently, and require different treatments. Here’s how to tell them apart and manage each one effectively.

Cold vs Flu: Key Differences

The common cold is caused by any of over 200 different viruses (most commonly rhinoviruses). It comes on gradually over 1–3 days and primarily affects the upper respiratory tract — runny nose, sore throat, mild cough. Fever is rare in adults and mild if present. You feel unwell but can generally continue daily activities with some effort.

Influenza (flu) comes on suddenly — often within hours. The hallmark is systemic illness: high fever (38.5°C+), severe muscle aches, profound fatigue, headache. Respiratory symptoms (cough, sore throat) are also present but the “body” symptoms dominate. With flu, you typically feel too ill to get out of bed. This distinction matters: true flu is a serious illness that kills 10,000–20,000 people in the UK in a bad year.

Hayfever: How It Differs from a Cold

Hayfever (allergic rhinitis) is an immune response to pollen, not an infection. Key distinguishing features: no fever, symptoms start immediately on pollen exposure, itchy eyes (very common in hayfever, rare in colds), sneezing in rapid bursts, clear watery discharge (not yellow/green as infection progresses). Hayfever is seasonal — following the pollen calendar — whereas colds can occur year-round.

Treating a Cold

There is no cure for the common cold. Treatment is entirely symptomatic:

  • Paracetamol or ibuprofen — for fever, sore throat, headache, muscle aches
  • Nasal decongestants — xylometazoline or oxymetazoline nasal spray (max 7 days) for blocked nose; pseudoephedrine oral tablets (ask at pharmacy)
  • Saline nasal rinse — genuinely effective, safe, and free from side effects
  • Honey — evidence supports its use for sore throat and cough, including in children over 1 year
  • Zinc lozenges — started within 24 hours of symptoms, may modestly reduce duration

Treating Flu

Rest and fluids are the cornerstone. Paracetamol or ibuprofen for fever and aches. Antiviral medication (oseltamivir/Tamiflu, zanamivir/Relenza) can reduce severity and duration when started within 48 hours — available on prescription and reserved for high-risk groups. The single best intervention is the annual flu vaccine, particularly for over-65s, pregnant women, and those with chronic health conditions.

Treating Hayfever

Oral antihistamines — cetirizine, loratadine, or fexofenadine. Non-drowsy once-daily options are now the standard. Start before pollen season begins for best effect.
Nasal corticosteroid sprays — the most effective treatment for persistent hayfever. Beconase, Flonase, Rhinacort. Require 1–2 weeks to reach full effect. Start 2 weeks before peak season.
Antihistamine eye drops — for itchy, watery eyes. Sodium cromoglicate (Opticrom), antazoline.
Barrier approaches — Vaseline around nostrils, wraparound sunglasses, keeping windows closed at peak pollen times, showering after being outdoors.

When to See a Doctor

See a GP or call 111 if: you have a fever above 39°C that doesn’t come down with medication, you have chest pain or difficulty breathing, symptoms are significantly worse after initial improvement (possible secondary bacterial infection), you’re at high risk (over 65, pregnant, immunocompromised, chronic health conditions), or symptoms persist beyond 10–14 days.

Shop our full range: Cold & Flu Medicines, Antihistamines, Nasal Sprays. Related: Hayfever Season Guide, Cold & Flu Remedies.