Author: Dr Tim Aung, Primary Care Practitioner, Brisbane, Queensland, Australia. DermNet NZ Editor-in-Chief: A/Prof Amanda Oakley, Dermatologist, Hamilton, New Zealand. Copy edited by Gus Mitchell. February 2019.
Aeroallergens are various airborne substances or inhalants, such as pollens, spores, and other biological or non-biological airborne particles that can cause allergic disorders. Inhalation or cutaneous contact with aeroallergens can trigger a release of proteins in the form of an allergic reaction on the skin and mucous membranes [1,2].
Airborne particles can also cause irritant reactions without causing an immunological response.
The most common aeroallergens causing disease are pollens and house dust mites. Pollens are derived from:
Other aeroallergens may include:
Combustion product irritants include:
Allergies only affect susceptible individuals (see allergies explained) whereas irritant reactions can affect anyone.
The prevalence of aeroallergens is quite variable from one region or country to another, depending on the climate, the local plants and animals, and the degree of pollution [3,4].
Climate change has been reported to contribute to the rise of some types of aeroallergens and a surge in allergic disorders [5–7].
In New Zealand, the aeroallergens are mainly grasses . The pollen season lasts for about 34 weeks beginning in July or August.
Although usually due to other factors, some common skin conditions are occasionally triggered or aggravated by aeroallergens [9–11]. How this occurs remains unclear (see figures below for proposed mechanisms).
Induction and effector mechanisms in type 1 hypersensitivity. Image from Microbiology and Immunology Online (courtesy of R Hunt, University of South Carolina) .
Aeroallergen pathways resulting in local IgE production in chronic rhinosinusitis with nasal polyps. Image from Allergy Asthma Immunol Res. 2015 (courtesy of G Gavaert, Ghent University) .
Aeroallergens commonly cause allergic rhinitis, allergic conjunctivitis, and allergic asthma, and may contribute to eosinophilic oesophagitis [14–16].
Skin conditions due to aeroallergens are less common. They include:
When a careful history and examination findings lead to suspicion of a cutaneous reaction to aeroallergens, investigations may include:
The avoidance and elimination of aeroallergen triggers can be challenging.
Be aware of the allergenic plants in your region and monitor the local pollen forecast. Stay indoors and consider taking antihistamines and other medications when the pollen count is high.
Thoroughly clean contaminated areas such as bathroom, laundry, and basement. Ventilate damp areas.
Clean and vacuum all pillows, mattresses, bed-sheets, towels, carpets, and upholstered furniture. Consider using pillow and mattress protectors.
Avoid contact with animals if possible. Bathe pets regularly.
The treatment of an aeroallergen allergic disease depends on the symptoms experienced.
Immunotherapy for allergic diseases (serial subcutaneous injections or sublingual) can reduce the reaction to aeroallergens in some patients.
See the DermNet NZ bookstore.
© 2019 DermNet New Zealand Trust.
DermNet NZ does not provide an online consultation service. If you have any concerns with your skin or its treatment, see a dermatologist for advice.