A rash may be a symptom of contact dermatitis, which occurs when a substance irritates a person’s skin. People can use a range of treatments to manage contact dermatitis.

Contact dermatitis is a skin condition that results from contact with certain substances that trigger an allergic reaction. The condition causes a person’s skin to become inflamed or develop a rash.

This article explores what contact dermatitis rash looks like, its causes, and how long it may last. The article also describes contact dermatitis treatment and when to contact a doctor.

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While contact dermatitis can affect any area of a person’s body, it commonly appears on people’s hands. They may observe a rash or experience other symptoms in the area of skin that made contact with the triggering substance, although symptoms can later spread to other areas.

When diagnosing contact dermatitis, doctors may look for:

People with severe cases of contact dermatitis may also experience:

The slideshow below includes images of contact dermatitis.

Doctors have not linked contact dermatitis to other allergic conditions and it does not run in families. People cannot spread contact dermatitis to others.

There are two main types of contact dermatitis, allergic and irritant. A person should speak with a doctor to help identify what triggers their contact dermatitis.

Irritant contact dermatitis

People with irritant contact dermatitis may develop a rash after their skin comes into contact with irritating substances. This will not include an immune response. Irritant contact dermatitis accounts for around 80% of all contact dermatitis cases, making it the most common type of contact dermatitis.

Substances that may cause irritant contact dermatitis include:

  • solvents
  • detergents
  • soaps
  • bleach or nickel-containing jewelry
  • other nickel-containing objects such as scissors, belt buckles, or zippers
  • makeup
  • hair dye
  • scratchy wool

If a person washes their hands with hot water and soap excessively, this may also trigger an irritant contact dermatitis reaction.

Allergic contact dermatitis

Allergic contact dermatitis involves a delayed allergic reaction. This means a person’s immune system produces the reaction. People often develop allergic contact dermatitis a day or two after their skin comes into contact with an allergen.

Common allergens include:

Photocontact dermatitis

People with photoallergic contact dermatitis, or photocontact dermatitis, develop rashes in sunlight. Photocontact dermatitis is a type of allergic contact dermatitis. It occurs after allergens on a person’s skin experience exposure to UV radiation, or sunlight.

Substances that may trigger photocontact dermatitis include:

Individuals may develop contact dermatitis symptoms up to 10 days after coming into contact with an allergen or irritant. A person with irritant contact dermatitis will typically develop symptoms within minutes of coming into contact with an irritant.

Allergic contact dermatitis may take up to 2–4 weeks to go away, even if a person receives treatment.

If a person avoids contact dermatitis triggers and follows their treatment plan, typically their symptoms will go away.

People with contact dermatitis who come into contact with irritants or allergens should wash the affected area using water and soap immediately.

Dermatologists commonly prescribe the following treatments to people with contact dermatitis:

Doctors also recommend people identify and then avoid the irritant or allergen causing their contact dermatitis.

Healthcare professionals may use patch testing to find the substances causing allergic contact dermatitis. A person will wear a patch containing small amounts of test substances for 2 days. The doctor will then examine the person’s skin to find which substance is causing an allergic reaction.

People with irritant contact dermatitis will often easily identify irritants. This is because symptoms can appear within minutes of contact.

A person’s contact dermatitis rash may clear up without treatment. However, doctors recommend people try to treat their symptoms. Healthcare professionals that specialize in dermatology can identify the best treatment and rule out other conditions.

Treatments that work for one person with contact dermatitis may not work for others. If a person finds that their symptoms do not go away, dermatologists can recommend a different approach.

People should not burst any contact dermatitis blisters, due to the risk of infection.

Contact dermatitis is a common condition caused by many triggers that may lead to a rash. Symptoms of contact dermatitis include itching, swelling, and redness in the skin.

The most effective treatment is for a person to identify and avoid their triggering allergens and irritants. However, healthcare professionals can also prescribe treatments to help manage the condition.