Eczema is a term used to describe various forms of dermatitis. Contact dermatitis is a specific type of disorder that causes irritation after the skin has been exposed to a particular substance. Contact dermatitis is further divided into two subtypes: irritant contact dermatitis and allergic contact dermatitis. Both present similar symptoms, but the mechanism triggering the response differs. 

Irritant Contact Dermatitis

Irritant contact dermatitis is the most common form of dermatitis. It occurs after an individual has had direct physical contact with the irritating substance. 

Symptoms may develop within a few hours, or one to two days after contact. It may also occur as a result of repeated, prolonged exposure. Some of the most common irritant substances include water, solvents, cleaning agents, lotions, cosmetics, soaps and shampoos. The oils found in some plants can also cause irritation.

Allergic Contact Dermatitis

Allergic contact dermatitis develops because the body's immune system reacts to the substance as an allergen. This type of dermatitis usually takes several years to develop; however, it is possible to become sensitized after only a few periods of exposure.

After sensitization, reactions to the irritating substance will appear in 48 hours or less. Thereafter, symptoms will always appear after contact, because it is not possible to eliminate an allergy. Generally, symptoms will become more severe with each episode of exposure.

Latex, topical antibiotics, nickel-plated jewelry, fabrics and cosmetics are some examples of products that may cause allergic contact dermatitis.

Symptoms of Contact Dermatitis

Depending upon the individual, symptoms can range from mild to severe. Touching the affected area will not cause it to spread to other areas of the body. Contact dermatitis will only affect substance contact areas. Symptoms usually manifest as: 

  • Redness
  • Rash
  • Itching
  • Small blisters or bumps
  • Patchy or scaly appearance
  • Appearance of severely cracked, dry skin
  • Larger fluid-filled blisters
  • Swelling
  • Mild to moderate pain 

Treatment

Most mild cases of contact dermatitis will clear up without medical intervention, provided the individual avoids further contact with the irritating substances. Mild cases of irritant contact dermatitis may respond to over-the-counter hydrocortisone creams. Symptoms of allergic contact dermatitis may respond to over-the-counter antihistamines. 

Individuals with severe or prolonged symptoms should consult with their physician. Eruptions that leave open wounds or seeping, broken blisters are prone to bacterial infections. A physician or dermatologist should examine conditions that are accompanied by uncomfortable and persistent itching. Intense, persistent itching can lead to a condition called neurodermatitis.

Neurodermatitis is a condition in which scratching makes the itching sensation more intense. This can also lead to infection, because the scratching tends to leave the open skin vulnerable to bacteria. If the irritating agent is unknown, the physician may order a patch test. Patches containing various substances are worn on the body for a couple of days. The doctor will look for any changes in the skin. 

Prevention

Identifying the substance may be difficult, as most people are exposed to many elements throughout the course of the day. Keeping a diary may assist in determining which substance is causing the irritation. If the substance cannot be avoided, it may help to wear gloves when handling the irritant.