State Board Nail Tech Practice Exam 2025 – All-in-One Guide to Nail Your Certification Success!

Head lice, itch mites, ringworms, and nail fungus are all caused by organisms that interact with the host’s body externally, leading to various ailments. These conditions arise from external parasites, which are organisms that live on or in a host and obtain nourishment from that host.

Head lice and itch mites specifically are classified as arthropods, which are a subset of external parasites, feeding on the host's blood or skin. Ringworm is actually a fungal infection, but it is still considered an external condition because the fungi invade and thrive on the outer layers of the skin. Nail fungus, similarly, affects the outer part of the nail.

In this context, internal parasites are typically involved in infections that occur within the host's body, while bacteria and viruses tend to cause infectious diseases in various ways, often not linked to parasitic behavior. Thus, selecting external parasites confirms the nature of these diseases, highlighting the relationship between the infectious agents and the symptoms experienced on the body’s surface.