There are two main Aspergillus infections that directly involve allergy. One is ABPA and the other is allergic fungal rhinosinusitis. In both cases the patient has an allergic reaction against the infecting material – this is completely different from inflammation of the infected tissue, which is the more usual case. The fungus does not invade the tissue but simply triggers the allergic response which can become chronic.
Breathing in spores from the air can cause more problems for these patients as they are already primed to react to the fungus. Therefore, patients with these conditions should avoid situations where they will be breathing in a large number of spores eg. damp houses, gardening, composting etc.
Once sensitised, adults tend not to get better; in fact they tend to accumulate more allergies, but these can be effectively treated. Children who become allergic tend to recover as they get older. See Web MD for more information about chronic allergies.
The medical charity Allergy UK explain what an allergy is very well:
What is Allergy?
The term allergy is used to describe a response, within the body, to a substance, which is not necessarily harmful in itself, but results in an immune response and a reaction that causes symptoms and disease in a predisposed person, which in turn can cause inconvenience, or a great deal of misery. An allergy is everything from a runny nose, itchy eyes and palate to skin rash. It aggravates the sense of smell, sight, tastes and touch causing irritation, extreme disability and sometimes fatality. It occurs when the body’s immune system overreacts to normally harmless substances. Allergy is widespread and affects approximately one in four of the population in the UK at some time in their lives. Each year the numbers are increasing by 5% with as many as half of all those affected being children.
What causes an Allergy?
Allergic reactions are caused by substances in the environment known as allergens. Almost anything can be an allergen for someone. Allergens contain protein, which is often regarded as a constituent of the food we we eat. In fact it is an organic compound, containing hydrogen, oxygen and nitrogen, which form an important part of living organisms.
The most common allergens are: pollen from trees and grasses, house dust mite, moulds, pets such as cats and dogs, insects like wasps and bees, industrial and household chemicals, medicines, and foods such as milk and eggs.
Less common allergens include nuts, fruit and latex.
There are some non-protein allergens which include drugs such as penicillin. For these to cause an allergic response they need to be bound to a protein once they are in the body. An allergic person’s immune system believes allergens to be damaging and so produces a special type of antibody (IgE) to attack the invading material. This leads other blood cells to release further chemicals (including histamine) which together cause the symptoms of an allergic reaction.
The most common symptoms are: sneezing , runny nose, itchy eyes and ears, severe wheezing, coughing, shortness of breath, sinus problems, a sore palate and nettle-like rash.
It should be understood that all the symptoms mentioned can be caused by factors other than allergy. Indeed some of the conditions are diseases in themselves. When asthma, eczema, headaches, lethargy, loss of concentration and sensitivity to everyday foods such as cheese, fish and fruit are taken into account the full scale of allergy be appreciated.
The Allergy UK website goes on to further explain what an intolerance is, what a multiple chemical sensitivity (MCS) is, and how these are all diagnosed and treated.
Hypersensitivity pneumonitis
Hypersensitivity pneumonitis (which used to be called extrinsic allergic alveolitis) is a condition that results from the lungs developing an inflammatory immune response to repeated exposure to airborne antigens. Aspergillus spores are one example of antigens that can cause this disease; others include particles from bird feathers and droppings, and spores from other moulds. There are many antigens that can be responsible for HP, and the condition is often referred to colloquially by its specific source — you may have heard of Farmer’s lung or Bird Fancier’s Lung, for example.
Symptoms include breathlessness, cough and feverishness, which can come on suddenly after exposure to the antigen, or more gradually. Acute HP develops rapidly after exposure; however, if the source is quickly identified and avoided, the symptoms will go away without causing permanent damage to the lungs. With chronic HP, the symptoms can gradually increase over years, causing fibrosis (scarring) of the lungs. In this case, it can be difficult to identify a specific cause. Treatment may include steroids to reduce inflammation, in addition to avoiding any identifiable sources of the illness.
Prognosis of HP is difficult to establish and varies based on factors such as age and the extent of lung fibrosis. Some papers have also suggested that clinical outcomes vary based on the type of antigen the patient is sensitive to; however, the largest study to date found no relationship between the type of antigen and outcomes of the condition.
Further information
Air quality information – Aspergillus website
Visit pollen & mould information here.
Airborne spores – University of Worcester
Spore count information across the UK. Find out how bad your area is this week.
UK NHS information
External links
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