The cause of the disease is the infectious egg of pinworm swallowed by man. Because infantile patients often scratch the orifice of anus with the hand, the egg of pinworm infects the fingers, giving rise to repeated infection. This affects the function of the spleen and stomach in transportation and transformation, resulting in the splenogastric failure to control transportation and transformation. In this case, dampness and heat accumulate internally. If the disease lasts long, it will consume and impair qi and blood.

Pinworm infections are contagious. People become infected by unknowingly ingesting microscopic pinworm eggs that can be found on many different surfaces, including:
1. Bed linens
2. Towels
3. Clothing (especially underwear and pajamas)
4. Toilets
5. Bathroom fixtures
6. Food
7. Drinking glasses
8.  Eating utensils
9. Toys
10. Kitchen counters
11. Desks or lunch tables at school
12. Sandboxes