Patch testing can be helpful in determining if you're allergic to a specific substance. Small amounts of different substances are placed on your skin under an adhesive coating. Your doctor then checks for a skin reaction under the patches.
Your doctor may be able to diagnose contact dermatitis and identify its cause by talking to you about your signs and symptoms, questioning you to uncover clues about the trigger substance, and examining your skin to note the pattern and intensity of your rash.
Your doctor may recommend a patch test to see if you're allergic to something. This test can be useful if the cause of your rash isn't apparent or if your rash recurs often.
During a patch test, small amounts of potential allergens are applied to adhesive patches, which are then placed on your skin. The patches remain on your skin for two to three days, during which time you'll need to keep your back dry.
Your doctor then checks for skin reactions under the patches and determines whether further testing is needed.
If home care steps don't ease your signs and symptoms, your doctor may prescribe medications. Examples include:
- Steroid creams or ointments. These topically applied creams or ointments help soothe the rash of contact dermatitis. A topical steroid may be applied one or two times a day for two to four weeks.
- Oral medications. In severe cases, your doctor may prescribe oral corticosteroids to reduce inflammation, antihistamines to relieve itching or antibiotics to fight a bacterial infection.
Lifestyle and home remedies
To help reduce itching and soothe inflamed skin, try these self-care approaches:
Avoid the irritant or allergen. The key to this is identifying what's causing your rash and staying away from it. Your doctor may give you a list of products that typically contain the substance that affects you. Also ask for a list of products that are free of the substance that affects you.
If you're allergic to the metal in a piece of jewelry, you may be able to wear it by putting a barrier between you and the metal. For example, line the inside of a bracelet with a piece of clear tape or paint it with clear nail polish.
- Apply an anti-itch cream or lotion to the affected area. A nonprescription cream containing at least 1 percent hydrocortisone can temporarily relieve your itch. A steroid ointment may be applied one or two times a day for two to four weeks. Or try calamine lotion.
- Take an oral anti-itch drug. A nonprescription oral corticosteroid or antihistamine, such as diphenhydramine (Benadryl), may be helpful if your itching is severe.
- Apply cool, wet compresses. Moisten soft washcloths and hold them against the rash to soothe your skin for 15 to 30 minutes. Repeat several times a day.
- Avoid scratching. Trim your nails. If you can't keep from scratching an itchy area, cover it with a dressing.
- Soak in a comfortably cool bath. Sprinkle the water with baking soda or an oatmeal-based bath product.
- Protect your hands. Rinse and dry hands well and gently after washing. Use moisturizers throughout the day. And 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.
Preparing for your appointment
You're likely to start by seeing your primary care doctor. He or she might refer you to a doctor who specializes in skin disorders (dermatologist).
Because appointments can be brief, it's a good idea to be well-prepared for your appointment.
What you can do
- List your signs and symptoms, including when they began and how long they've lasted.
- Avoid any substances that you think may have caused the rash.
- Make notes about any new products you've started using and any substances that regularly come in contact with your affected skin areas.
- Make a list of all the medications and supplements you take. Even better, take along the original bottles and a list of the dosages and directions. Include any creams or lotions you're using.
- List questions to ask your doctor.
For contact dermatitis, some basic questions you could ask your doctor include:
- What might be causing my signs and symptoms?
- Are tests needed to confirm the diagnosis?
- What treatments are available, and which do you recommend?
- Is this condition temporary or chronic?
- Can I wait to see if the condition goes away on its own?
- Will scratching spread the rash?
- Will popping the blisters spread the rash?
- What skin care routines do you recommend to improve my condition?
- How can I prevent this in the future?
What to expect from your doctor
Your doctor is likely to ask you questions such as the following:
- When did you begin noticing symptoms?
- How often do you have symptoms?
- Have your symptoms been continuous or occasional? Do they get better over the weekend or during vacation?
- Does anything seem to make your symptoms better or worse?
- Have you started using any new soaps, lotions, cosmetics or household products?
- Does your work or a hobby involve using products that often come in contact with your skin?
Oct. 04, 2018
- Goldner R, et al. Irritant contact dermatitis in adults. https://www.uptodate.com/home. Accessed April 27, 2017.
- Goldsmith LA, et al., eds. Allergic contact dermatitis. In: Fitzpatrick's Dermatology in General Medicine. 8th ed. New York, N.Y.: The McGraw-Hill Companies; 2012. http://www.accessmedicine.mhmedical.com. Accessed April 27, 2017.
- Contact dermatitis. Merck Manual Professional Version. https:/www.merckmanuals.com/professional/dermatologic-disorders/dermatitis/contact-dermatitis. Accessed April 27, 2017.
- AskMayoExpert. Contact dermatitis. Rochester, Minn.: Mayo Foundation for Medical Education and Research, 2016.
- AskMayoExpert. Poison ivy rash. Rochester, Minn.: Mayo Foundation for Medical Education and Research, 2016.
- Fonacier L, et al. Contact dermatitis: A practice parameter — Update 2015. Journal of Allergy and Clinical Immunology Practice. 2015;3(3 suppl):S1.
- Gibson LE (expert opinion). Mayo Clinic, Rochester, Minn. May 7, 2017.