What it is
Moulds release tiny spores into the air to spread, much as plants release pollen. In some people the immune system overreacts to them, causing symptoms like hay fever. Spores can also set off asthma.
Symptoms
- Sneezing, a runny or blocked nose.
- Itchy, watery eyes.
- A cough, wheeze or tight chest, especially if you have asthma.
- Symptoms that are worse in damp rooms, when raking leaves, or on warm, humid days.
Mould or pollen?
| Mould | Pollen | |
|---|---|---|
| Worst months outdoors | July to October | March to July |
| Weather | Warm, humid and damp days | Warm, dry, breezy days |
| After rain | Can get worse | Usually better |
| Indoors in winter | Common in damp homes | Almost none |
Outdoor mould season
Outdoor spores peak from late summer into autumn, on warm, humid days and around harvest time. Piles of wet leaves, compost heaps and cut grass are hotspots. Late-season sneezing in August and September is often mould rather than pollen.
- Wear a mask when raking leaves or turning compost, or ask someone else to.
- Keep windows closed on warm, muggy days in late summer.
- Don’t keep compost bins right outside doors and windows.
Indoor mould
Indoors, mould grows where condensation sits. Keep rooms aired and dry, use extractor fans, and dry clothes outside or in a vented dryer. Our guide to allergies in winter has a full list.
What helps
- A pharmacist can recommend antihistamines, steroid nasal sprays or eye drops. They work for mould as they do for pollen.
- See your GP if symptoms carry on, or if you wheeze. A skin prick or blood test can confirm a mould allergy.
- If you have asthma, make sure your action plan covers damp, mouldy conditions.
Questions
When is mould allergy season in Ireland?
Outdoors, from about July to October, peaking on warm, humid days in late summer and autumn. Indoors, mould can cause symptoms all year in damp homes, and is often worse in winter.
Can mould make you sneeze like hay fever?
Yes. Mould spores cause the same sneezing, runny nose and itchy eyes. The timing is the clue: mould is worse in late summer, autumn and damp weather.
Does rain make mould allergy worse?
It can. Rain washes pollen out of the air, but damp, warm weather afterwards helps mould grow and release spores.
This is general information, not medical advice. If you are worried about symptoms, talk to your pharmacist or GP.
Further reading
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