When people come in contact with poison ivy, the urushiol can cause an allergic skin reaction that produces reddish, itchy, and painful inflammation of the skin (dermatitis). Close relatives of poison ivy plants that produce similar dermatitis symptoms are poison oak and poison sumac.
Health conditions that may cause excessive sweating include: 1  Diabetes. 2  Endocarditis. 3  Fever of undetermined cause.  Generalized anxiety 1  disorder. Hiatal hernia.  Heat 1  exhaustion. HIV/ 2 AIDS. Hyperhidrosis.  Hyperthyroidism (overactive 1  thyroid) 2  Leukemia.  Malaria.
Excessive sweating may not be the result of a physical malady, but a symptom of stress, hot flashes during menopause, or the side-effect of taking certain medications (such as beta blockers and tricyclic antidepressants), Mayo Clinic experts note. But excessive sweating can also have no underlying cause.