Contact dermatitis is a condition in which your skin reacts to a substance it has come into contact with. Your skin becomes itchy, red, or sore. You may also get blisters or bumps. The rash isn’t contagious or life-threatening, but it can be very uncomfortable.
There are two types of contact dermatitis.
This is the most common type. It can be caused by contact with acids, alkaline materials such as soaps, detergents and fabric softeners. The reaction usually looks like a burn. Anyone can develop a contact irritant contact dermatitis if their skin is in contact with an irritant for long enough, often enough, or in a strong enough concentration.
Other materials that may irritate your skin include:
- Long-term exposure to urine e.g. wet nappies
- Shampoos and hair dyes
- Latex (rubber) gloves
- Pesticides or weed killers
Allergic contact dermatitis
This is caused when your skin comes in contact with a substance that causes an allergic reaction (see what is an allergy).
Common allergens include:
- Nickel, which is used in jewelry, buckles and many other items
- Plants such as poison ivy
- Medications, such as antibiotic creams and oral antihistamines
- Balsam of Peru is used in many perfumes, cosmetics, mouth rinses and flavorings
- Formaldehyde in adhesives and solvents
- Fragrances in perfumes, cosmetics, soaps, and moisturizers
- Skin tattooing and black henna
- Fabrics and clothing
You may not have a reaction to a substance when you are first exposed to it. However, you may become more sensitive and develop a reaction if you use it regularly.
Some products cause a reaction only when the skin is also exposed to sunlight. These include:
- Shaving lotions
- Sulfa ointments
- Some perfumes
- Coal tar products
- Oil from the skin of a lime
Symptoms vary depending on the cause and whether the dermatitis is due to an allergic reaction or an irritant. The same person may also have different symptoms over time. Symptoms occur at the site of contact. Irritant contact dermatitis happens soon after contact with the offending agent. Allergic contact dermatitis appears 1 to 2 days after exposure to the allergen.
General symptoms include:
- Redness and swelling of the skin (Hives)
- Itching (can be very severe in allergic contact dermatitis)
- Blistering of the skin
- Crusting and oozing
The severity of the rash depends on:
- How long you’re exposed
- The strength of the substance that caused the rash
- Burning or pain (more common in the irritant form of contact dermatitis)
- Dry, red, rough skin with fissures /cuts (more common in the irritant form of contact
- Scaling and temporary thickening of the skin (after recurrent exposure)
- Environmental factors, such as temperature, airflow and sweating from wearing gloves
- Your genetic makeup, which can affect how you respond to certain substances
- The diagnosis of contact dermatitis is based upon your full story of how and when the suspected substances affected your skin and an examination by the doctor. If symptoms improve after the offending substance is removed, this supports the diagnosis.
Patch testing may be recommended where the cause is unclear or symptoms are recurrent. This test may be performed by a dermatologist or allergist. On the first visit, small patches of possible allergens are applied to the skin. These patches are removed 48 hours later to see if a reaction has occurred. A third visit, about 2 days later, is done to look for any delayed reaction.
If you have already tested a material on a small area of your skin and noticed a reaction, you should bring the material with you. Other tests may be needed to rule out other possible causes, including skin biopsy or culture of the skin lesion.
The best treatment is to identify and avoid the substances that may have caused the contact dermatitis.
- Thoroughly wash skin with soap and water as soon after the exposure as possible.
- Choose mild soaps without dyes or perfumes. Rinse completely, pat your skin dry and apply moisturizer.
- Soak in a comfortably cool bath. Sprinkle the water with baking soda or an oatmeal-based bath product.
- Wash clothing and all objects that may have come in to contact with the substance e.g. plant resins (poison ivy or poison oak) to prevent re-exposure.
- Use wet, cold compresses to soothe and relieve inflammation if blisters are broken.
- Avoid scratching. Trim your nails. If you can’t keep from scratching an itchy area, cover it with a dressing and bandage.
- Wear smooth-textured cotton clothing. This helps avoid irritation.
- Protect your hands with gloves. Choose gloves based on what you’re protecting your hands from. For example, plastic gloves lined with cotton are good if your hands are often wet.
- Emollients or moisturizers help keep the skin moist, and also help skin repair itself. They protect the skin from becoming inflamed again. They are a key part of preventing and treating contact dermatitis.
- Wet dressings and soothing lotions may be recommended to reduce other symptoms (see wet wraps).
- Topical corticosteroid creams are used for the treatment of eczema and may help to reduce the inflammation. Do not use more medicine or use it more often than your doctor advises you to use it.
- Oral antihistamines may help to relieve itching.
- Your doctor may also prescribe other creams or ointments, such as tacrolimus or pimecrolimus, to use on the skin.
- For severe reactions, always contact your health care provider. Oral steroids or a steroid injection may be indicated for more severe or widespread reactions.
Will the rash ever go away?
Contact dermatitis clears up without complications in 2 or 3 weeks in most cases. However, it may return if the substance that caused it cannot be found or avoided.
You may need to change your job or job habits if it is caused by exposure at work.
Bacterial skin infections may occur on top of contact dermatitis and make it more difficult to treat.
Call your health care provider if:
- You have symptoms of contact dermatitis
- The skin reaction is severe
- You do not get better after treatment
- Signs of infection such as tenderness, redness, warmth, or fever
A medical specialist with a special interest and skill in allergy might be able to help. See the list of health professionals with skills in allergy on the AFSA website.