Dermatitis is a skin disease characterised by redness, swelling, heat and pain or itching. It is in fact an inflammation of the skin, both external and internal. There are several causes behind the development of dermatitis. There are a few factors that are considered as probable causes of dermatitis. Recent studies showed that the disease is caused due to interactions between the immune system of a person, the environment and genetics. The people suffering from dermatitis often have a hyper sensitive immune system and they tend to respond to numerous irritants and allergens. Many dermatitis-affected people have a family history of allergic conditions. Apart from that, a genetic predisposition to the disease can also be aggravated by variables like food allergies, infections, irritating chemicals, temperature, humidity and stress. The causes of dermatitis help in diagnosing the disease at an early stage and following proper treatment methods. There are many types of dermatitis and each type has different causes of formation.

One of the major causes of dermatitis is certain chemical substances, which are also known as irritants. These irritants can reach inside the skin through blood stream. Apart from the chemical substances, more than 100 different plants have also been identified as potential causes of dermatitis. The plants are kinds of irritants and can cause dermatitis in susceptible people. In this case, the onset of dermatitis is usually acute and the symptoms are found about an hour or two after contact is made. Having external contacts with irritating chemicals is another cause of dermatitis. Most cases of industrial dermatitis that occur on the hands or forearms are caused due to external contacts.

Another common cause behind the development of dermatitis is intake of certain drugs. The application of drugs like atropine, belladona, carbolic acid, iodine, mercury, penicillin, sulphonamides, sulphurs, tars, turpentine, etc. can sometimes cause dermatitis. Apart from these, the substances like hair dyes, bleaches, skin tonics, nail polish, perfume, wool, silk, nylon, floor-wax, various detergents, etc. can also cause dermatitis. The other common causes of dermatitis include lack of caution in diet, deficiency of vitamin A, pantothenic acid, nervous and emotional strains, etc. Dermatitis may flare-up in response to extreme humidity and temperature, as well. Degreasing agents like soaps can also cause dermatitis, if used too frequently over a short time. They can cause dryness, redness, fissuring and irritation of the skin and gradually cause dermatitis. Certain inhaled irritants like pollen or house dust mites; viral or bacterial infections; certain foods in people having food allergies; dry skin; weakness due to illnesses like cold or flu; changes in hormone levels; etc. are also some of the causes of dermatitis. Psychological stresses can provoke or aggravate dermatitis, as well, presumably by suppressing the normal immune mechanisms.