There is no clear cause of appendicitis. Fecal material is thought to be one possible cause of obstruction of the appendix. Bacteria, viruses , fungi, and parasites can result in infection, leading to the swelling of the tissues of the appendix wall. The various infecting organisms include Yersinia species, adenovirus , cytomegalovirus, actinomycosis, Mycobacteria species, Histoplasma species, Schistosoma species, pinworms , and Strongyloides stercoralis . Swelling of the tissue from inflammatory bowel disease such as Crohn's disease also may cause appendicitis.
Transdermal patches (adhesive patches placed on the skin) may also be used to deliver a steady dose through the skin and into the bloodstream. Testosterone-containing creams and gels that are applied daily to the skin are also available, but absorption is inefficient (roughly 10%, varying between individuals) and these treatments tend to be more expensive. Individuals who are especially physically active and/or bathe often may not be good candidates, since the medication can be washed off and may take up to six hours to be fully absorbed. There is also the risk that an intimate partner or child may come in contact with the application site and inadvertently dose himself or herself; children and women are highly sensitive to testosterone and can suffer unintended masculinization and health effects, even from small doses. Injection is the most common method used by individuals administering AAS for non-medical purposes.