Contact Dermatitis

Contact Dermatitis

Contact Dermatitis

Contact Dermatitis


Contact Dermatitis

Contact dermatitis is inflammation of the skin that results from direct contact of a substance with the surface of the skin, which may or may not be related to an allergy. Some substances are always irritating to the skin.


A person develops contact dermatitis when something that touches the skin does one of the following:

  • Irritates the skin
  • Causes an allergic reaction

There are two types of contact dermatitis:

  • Irritant contact dermatitis is the most common form and develops when substances such as solvents or other chemicals irritate the skin. The exposure produces red, often more painful than itchy, patches on the involved skin areas.
  • Allergic contact dermatitis is an immune response triggered by an allergen. Nickel, perfumes, dyes, rubber, latex, topical medications and cosmetics frequently cause allergic contact dermatitis. More than 3,600 substances can cause allergic contact dermatitis.
  • The differences between irritant and allergic contact dermatitis can be confusing. Questions may be addressed below in the Frequently Asked Questions section.

Risk Factors

Anyone can develop contact dermatitis. Your risk factor may be increased if you are in regular contact with an irritant or allergen, or if you already have allergies to certain substances, such as plants, chemicals, or medications. People working in certain professions have a higher risk. Sometimes this is referred to as occupational dermatitis. It is important to know that the more you come in contact with a substance, the more likely you are to develop an allergy to it and for it to be the cause of allergic contact dermatitis.

People who are more likely to get occupational dermatitis include:

  • Nurses (and other health care workers)
  • Beauticians
  • Bartenders
  • Chefs (and others who work with food)
  • Florists (and others who work with plants)
  • Construction workers
  • Janitors
  • Mechanics
  • Plumbers


Signs and symptoms of contact dermatitis rarely appear with immediate contact. Most symptoms of contact dermatitis appear within 24-72 hours. An allergic reaction requires more than 1 exposure to the substance, but after this, a reaction can occur quickly. Rarely, people can develop a severe allergic reaction known as anaphylaxis (an-uh-fuh-lax-sis). Symptoms occur within seconds or minutes. A person may have:

  • Difficulty breathing due to swelling in the throat
  • Swollen face and/or eyes
  • Confusion

The entire body reacts during these events. If anyone has any of these symptoms, seek immediate medical care.

During normal contact dermatitis reactions, when signs and symptoms do appear, you may have:

  • Itchy skin, which can be intense
  • Rash, including red, swollen, hot skin
  • Excessively dry skin
  • Burning
  • Stinging
  • Hives, which are round welts on the skin that itch
  • Fluid-filled blisters
  • Oozing blisters that leave crusts and scales

If exposure to the allergen continues, your skin may:

  • Flake and crack
  • Become scaly
  • Darken, thicken, and feel leathery


To diagnose this common skin condition, dermatologists:

  • Examine your skin and the developing rash
  • Review your medical history
  • Ask questions about your lifestyle to determine what may be causing the rash

If your dermatologist suspects that you have an allergy, patch testing may be recommended. A patch test involves applying panels to your skin that contain small amounts of possible allergens for a period of time. After this time, the patches are removed to inspect the skin for reactions. Relevance must be kept in mind when considering the results of a patch test. For instance, if the substance a patient reacts to is not something they come in contact with regularly, it is not likely to be the source of the contact dermatitis.


American Academy of Dermatology American Academy of Allergy, Asthma, and Immunology



Treatment is the same for both types of contact dermatitis.

The steps involved during treatment are:

  • Avoid or lessen the exposure to the substance that is causing the rash.
  • Treat the rash, often using antihistamine pills, moisturizer, and a corticosteroid cream.
  • Severe reactions may require stronger medications, such as prednisone.
  • Wet dressings and oatmeal baths can help soothe symptoms until the rash clears.

By avoiding what caused the rash, most people can avoid flare-ups.

If you work with substances that caused the rash, you can still avoid a rash. Your dermatologist can recommend ways to work and products to use. More than 80% of people diagnosed with occupational dermatitis successfully manage the condition and recover without any problems.


American Academy of DermatologyAmerican Academy of Allergy, Asthma, and Immunology


What is contact dermatitis?

Contact dermatitis is a condition in which the skin becomes red, sore, or inflamed after direct contact with a substance. There are two types of contact dermatitis: irritant and allergic.

What is a patch test?

Patch testing is a diagnostic test that may determine which allergen is causing the skin to become irritated in the case of allergic contact dermatitis.

What is occupational dermatitis?

Occupational dermatitis is a skin disorder caused by coming into contact with certain substances in the workplace. It can have long term consequences for workers' health and in extreme cases it can hinder a person's ability to continue working. Research has indicated that 10 years after the condition first occurs, up to 50% of affected workers will still have some skin problems.

What is irritant contact dermatitis?

In irritant contact dermatitis, the substance that damages the skin is known as the irritant. A highly irritating substance is known as a corrosive. Irritant dermatitis makes up about 80% of contact dermatitis cases. The other 20% are allergic.

There are several causes of skin damage that can lead to irritant contact dermatitis:

  • Detergents, soaps (such as in repeated hand washing), or the use of solvents can remove the protective oily layer and leave the skin exposed to damage. Plain water, when the skin is exposed repeatedly, can do this as well.
  • Physical damage such as friction and minor cuts can break down the protective layer and allow access to irritating substances that can burn the skin layer.

Irritation is analogous to a chemical burn. It acts by eroding or burning the outer protective layers of the skin. Irritant contact dermatitis usually occurs only on the parts of the body that come in direct contact with the irritant substance e.g. hands, forearms, or face.

What is allergic contact dermatitis?

In this case, a substance causes a person to become sensitized or to develop an allergic reaction some time after initial contact. The type of allergic mechanism is known as Type IV or delayed hypersensitivity. People do not become allergic to a substance immediately at first contact. The sensitization period (the time between contact and the development of an allergy) can vary from a number of days to months or even years. The risk of becoming allergic depends on several factors:

  • The nature of the substance. Substances with a higher likelihood to cause allergy is known as a skin sensitizer.
  • The nature of contact. The higher or more repeated the exposure, the more likely it is for the individual to develop sensitization.
  • The vulnerability of the host. Individuals with skin affected by other skin conditions like eczema are more likely to develop sensitivities. Individuals with a previous history of non allergic dermatitis ARE more vulnerable. This may be because the sensitizer may more easily enter the bloodstream in those individuals.

Once the individual becomes sensitized, each time he/she comes into contact with the sensitizing substance, even in very small amounts, dermatitis will develop. This is different from irritant dermatitis which is dose related.

Sensitization is specific to one substance or to a group of substances that are chemically similar. Once sensitized, a person is likely to remain so for life. In allergic dermatitis, the rash can occur in areas of the skin not in direct contact with the substance.

Common sensitizers are chromates (found in cement), nickel (jewelry), epoxy resins, formaldehyde, wood dust, flour, printing plates, chemicals and adhesives.


Health & Safety Authority


Contact Dermatitis Videos
menu btn

Appointment Request

this is test popop

Other Links