The vast majority of us carry a smartphone at all times.
Yet, many people overlook just how filthy and germ-ridden the device screens can become, with a University of Arizona study finding that phones carry 10 times more bacteria than most toilet seats.
And now, researchers from the American College of Allergy, Asthma, and Immunology have reported that smartphones can also be "reservoirs of allergens".
In a study using simulated phone models, the team discovered elevated levels of cat and dog allergens, as well as beta-glucans (BDG) and endotoxin.
"Smartphones showed elevated and variable levels of BDG and endotoxin, and cat and dog allergens were found on smartphones of pet owners," explained lead author Hana Ruran. "BDGs are found in fungal cell walls and have been found in many environments and surfaces causing chronic airway and irritant symptoms - making BDGs a consistent marker to study problematic mould. Endotoxin is a potent inflammatory agent."
In addition, the researchers found that certain chemicals were most effective at removing the allergens.
"Combination chlorhexidine/cetylpyridinium was the most effective in reducing BDG and endotoxin and combination benzyl benzoate/tannic acid most effectively reduced cat and dog allergens on smartphones," added co-author Dr Peter Thorne. "The study demonstrates exposure to inhalant allergens and molecules that trigger innate immune reactions from a source most people haven't considered. If you have allergies or asthma, you may want to think about cleaning your smartphone more often to minimise exposure to these allergens and asthma triggers."