What is contact dermatitis?
Contact dermatitis is a rash that occurs on your skin after touching certain substances. There are two types of contact dermatitis: allergic and irritant. Contact dermatitis can affect any part of the body.
Anyone can develop either allergic or irritant contact dermatitis, but people who frequently handle known allergens or irritants at home or at work are the most commonly affected. Depending on the cause, contact dermatitis can be a short-lived or long-term issue.
Most common symptoms
Allergic contact dermatitis causes a rash with intense itching that occurs hours to days after exposure. The rash is usually red, scaly-looking, and just where the allergen touched the body. For example, someone with a nickel allergy who wears nickel-containing earrings might only have the rash on their earlobes. In more severe cases, blistering may occur, or the rash might spread beyond the initial area of contact.
Irritant contact dermatitis causes a red, sometimes swollen rash that tends to be more painful and irritated rather than itchy. It can occur quickly after contact, especially if it was a chemical exposure. Hands tend to be the most affected area.
In both types of dermatitis, long-term exposure can cause several chronic changes to the skin, like thickening or cracking. Symptoms will gradually improve once the offending trigger is avoided.
Allergic contact dermatitis
- Scaly appearance
Irritant contact dermatitis
- Pain or irritation
Other symptoms you may have
- Blistering in more severe cases
- Skin thickening tends to occur with rashes that have been ongoing for a long time
One of the most interesting facts about contact dermatitis is that it can occur to any product or ingredient, even one you’ve been using for a very long time. We routinely see people who suddenly develop a rash from a hair dye or cosmetic product they’ve used for years. —Dr. Amrita Khokhar
Allergic contact dermatitis is more likely if you have repeated exposure to potential allergens. People with eczema may be more likely to develop allergic contact dermatitis.
Commonly encountered allergens include:
- Metals like nickel or gold
- Preservatives found in skincare products
- Dyes used in clothing
- Topical antibiotics
- Hair dyes containing paraphenylenediamine (PPD)
- Plant oils from poison ivy, poison oak, or poison sumac
Allergic contact dermatitis is more common in certain occupations:
- Healthcare workers: Latex and other rubber components found in gloves
- Hairdressers and beauticians: Hair dye, hair-relaxing chemicals
- Landscapers, gardeners, other agricultural workers: Plants like poison ivy
- Food handlers: Direct contact with food proteins, like in wheat or shellfish
- Construction workers: Chemicals found in cement
Irritant contact dermatitis is more common in occupations with frequent exposure to certain substances:
- Cutting agents
- Prolonged water contact
Contact dermatitis isn’t just itchy or uncomfortable; it can impact your quality of life and ability to work. It can be helpful to see a doctor if any of the following apply:
- The rash lasts for several days or even weeks.
- Your hands are affected.
- You are not sure what’s causing the rash.
- You think the rash might be from something at work.
Contact dermatitis in children
Babies and infants can develop both allergic and irritant contact dermatitis. Some common culprits to look out for include:
- Baby wipes (allergic)
- Snaps or zippers that contain nickel (allergic)
- Fragrances in soaps and laundry detergents (allergic)
- Their own saliva (irritant)
- Wet or soiled diapers (irritant)
- Certain foods like tomatoes or citrus (irritant)
Contact dermatitis causes
Allergic contact dermatitis occurs when the immune system becomes sensitive to a particular substance. The next time you handle the substance, your body reacts by causing the area to become red, inflamed, and itchy. This can happen within hours to days.
Irritant contact dermatitis occurs when a substance causes direct injury to your skin, rather than an allergy. The immune system doesn’t play a role in this type of dermatitis. While stronger chemicals are well-known causes, even harmless actions like frequent hand-washing or working with wet materials can lead to irritant contact dermatitis.
The most common misconception I hear is that “all natural” products are safer to use and that you can’t develop an allergic reaction from them. In fact, these kinds of products often contain plant oils, fragrances, and other derivatives that can be highly allergenic and irritating. —Dr. Khokhar
Contact dermatitis treatment
Although contact dermatitis is one of the most common causes of hand dermatitis, some adults also develop eczema (atopic dermatitis) on their hands. Atopic dermatitis is more an issue with your skin barrier than a reaction to outside substances. How you treat and manage it is slightly different from what you do for contact dermatitis. —Dr. Khokhar
First, do your best to avoid the substance that is causing the reaction. Patch testing is a type of allergy test that helps you figure out your allergic triggers.
If irritant contact dermatitis is suspected, reviewing exposures at home and at work can help identify the cause. Protecting your skin with proper handwashing, use of gloves, and frequent moisturizing, can help.
Allergic contact dermatitis may require topical steroids. These help treat the inflammation, but will not prevent the rash from recurring if you come into contact with it again.
Contact dermatitis can be treated using the following:
- Topical steroids: These medications come in varying different strengths and are over-the-counter or by prescription. The strength and dosage will depend on how severe your reaction is. Some examples include hydrocortisone, triamcinolone, and clobetasol.
- Oral steroids: During a severe reaction, oral steroids like prednisone might be used for a short period of time.
- Antihistamines: While medications like diphenhydramine (Benadryl), cetirizine (Zyrtec), loratadine (Claritin), and fexofenadine (Allegra) might commonly be prescribed for itching, they are not as useful as steroids. Sedating antihistamines like diphenhydramine can help you sleep at night if the itching is intense.
If you are diagnosed with contact dermatitis and prescribed medication, you may need to follow up with your doctor to see if your rash has improved or gone away. If your rash is persistent or returns after treatment, you may need further testing or a referral to an allergy specialist.
The most effective way to prevent contact dermatitis is to try to avoid exposing yourself to potential triggers in the first place. Understandably, this can be difficult to do.
If you frequently handle common allergens or irritants at work, taking steps like protecting your hands with rubber gloves, maintaining good skin health with moisturizers, and keeping an eye on your skin can help. Finally, if you notice that you’re developing a rash, try not to scratch the area—this can make the rash worse.
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