Alternaria mould allergy
Allergy to Alternaria mould spores.
About alternaria mould allergy
Alternaria is a common outdoor mould that grows on decaying plants, soil, compost and rotting leaves. It releases large numbers of airborne spores, particularly on warm, dry, windy days in late summer and early autumn, though smaller amounts circulate at other times and indoors. In sensitised people, the immune system treats proteins in these spores as a threat and mounts an IgE-mediated allergic response. Mould allergy is less common than grass or dust mite allergy but is well recognised, and Alternaria in particular is noted internationally as one of the mould allergens most strongly linked with asthma.
The usual picture is allergic rhinitis: sneezing, a runny or congested nose and itchy, watery eyes when spore counts are high. Alternaria has a fairly strong association with asthma, so exposure can also bring coughing, wheeze and chest tightness, and it may contribute to eczema flares in some people. Symptoms are seldom life-threatening, but poorly controlled asthma is always potentially serious, and disturbed sleep from a blocked nose can affect concentration at school and work.
Avoidance is difficult outdoors, but it helps to limit gardening and compost turning when counts are high, wear a mask for such tasks, and keep indoor damp under control by fixing leaks and ventilating well. Diagnosis is confirmed with skin-prick or specific-IgE blood tests. Treatment follows the usual ladder of antihistamines and steroid nasal sprays, with allergen immunotherapy considered for selected, troublesome cases. See a GP if symptoms are persistent, disturb sleep, or come with worsening asthma.
Common triggers
- Alternaria mould and products containing it
Symptoms
- Sneezing and a runny or blocked nose
- Itchy, red or watery eyes
- Itchy throat, nose or ears
- Coughing or wheezing
- Worsening of asthma
Avoidance & management
- Reduce exposure to the trigger where possible
- Keep windows closed during high-exposure periods
- Use air filtration and wash bedding regularly
- Shower and change clothes after exposure
- Use prescribed antihistamines, nasal sprays or preventers
Sources & references
Allergy safety: what everyone should know
Mild-to-moderate reaction signs
- Itching, hives or a raised rash
- Swelling of lips, face or eyes
- Tingling mouth, sneezing, runny nose
- Stomach pain, nausea or vomiting
Anaphylaxis — call 999 (UK) or 112 (EU) immediately
- Difficult or noisy breathing, wheeze, persistent cough
- Swelling of the tongue or tightness in the throat
- Dizziness, collapse, pale and floppy (young children)
- Use an adrenaline auto-injector (e.g. EpiPen) at once if prescribed, then call an ambulance even if symptoms improve
Allergy or intolerance? A true allergy involves the immune system and can escalate quickly; an intolerance (e.g. lactose intolerance) is unpleasant but not life-threatening. The symptoms overlap, so self-diagnosis is unreliable.
Getting tested: home-testing kits based on IgG are not diagnostically valid. If you suspect an allergy, ask a GP for referral to an allergy clinic for skin-prick or specific-IgE testing and a supervised food challenge where appropriate.