Chemicals cause skin reactions either by direct contact, such as with an acid, or as a result of allergy or sensitization to a specific chemical. Allergic contact dermatitis is the result of changes in the cellular immune response. Chemicals that sensitize easily are usually fat soluble and reactive with tissue proteins. For allergic contact dermatitis to occur, a period of five to seven days or more is required for incubation. Mechanical causes, such as friction, can produce calluses, blisters, abrasions and fungus site development.
Pressure can create bony projections, skin atrophy, and dead skin tissue.
Calluses and fissures can be produced by repetitive hand motion and by the use of certain types of tools. Physical agents, such as heat and cold, can also contribute to dermatitis. Sweat-related hand dermatitis can be caused when using gloves. Radiation factors can cause skin overgrowth, surface burns, photosensitivities, and skin cancer. Frostbite, especially of the hands, can be severe enough to destroy the deeper tissues of the skin.