Bronchospasm or a bronchial spasm is a sudden constriction of the muscles in the walls of the bronchioles. It is caused by the release (degranulation) of substances from mast cells or basophils under the influence of anaphylatoxins. It causes difficulty in breathing which can be very mild to severe. Bronchospasms are one of several conditions associated with cold housing. Some of the things that can cause bronchospasms are: consuming foods, taking medicines, allergic responses to insects, and fluctuating hormone levels, particularly in women.