1 Poison ivy, poison oak, and poison sumac are plants than can cause an itchy rash upon contact. 2  A substance called urushiol, found in these plants, causes the rash. 3  The rash is not contagious.  The rash usually disappears in one to three weeks.
Common factors that can cause clogged ears are wax buildup, air flow blockage to the Eustachian tubes, pressure differences in the middle ear, and cold and sinus problems. Clogged ears can affect people of all ages, but is most common among children, especially when they have colds.
Clogged ears during pregnancy is due to an increase in blood flowing to your mucous membranes. More specifically, there might be fluid now that build up in your Eustachian tube and/or your Eustachian tube is swollen. Women report that the stuffed ears go away by themselves but sometimes only after the pregnancy.