What is Allergic Contact Dermatitis?
Allergic contact dermatitis (ACD) is a type of delayed allergic reaction where your immune system reacts to a small molecule that comes in contact with your skin, such as a chemical in a beauty product or a metal. This small molecule, also called a hapten, has a weight less than 500 daltons. When this molecule combines with a protein in your body, it forms a complex that causes an expansion of allergen-specific T cells – a type of white blood cells that respond to allergens. This is known as sensitization.
Then, when you’re exposed to the same allergen again, your skin can develop an allergic reaction, causing a condition called dermatitis, which is inflammation of the skin that makes it red, itchy, and swollen. This whole process is called an allergic contact dermatitis.
ACD is actually responsible for 20% of skin allergies, depending on where you live, your habits, what you enjoy doing, and even what kinds of preservatives are allowed in your area. For example, a preservative called quaternium-15 is allowed in the United States but not in Europe. That’s why your skin allergies may differ greatly based on these factors.
What Causes Allergic Contact Dermatitis?
Allergic contact dermatitis is a type of skin inflammation caused by an overreaction of the body’s defense system, known as a type 4 hypersensitivity reaction. This happens when an irritating substance or allergen touches the skin, triggering an immune response. Often, the shape and location of the rash can help identify what caused it. For example, a rash around the wrist could be due to an allergy to a bracelet or watchband.
A common cause of allergic contact dermatitis is poison ivy. After touching the plant, you might notice itchy, red streaks on your skin where the plant made contact.
Nickel, a type of metal, can also cause allergic contact dermatitis. You might see skin irritation where you wear necklaces or earrings containing this metal.
Other common irritants include rubber gloves, hair dyes, textile chemicals, preservatives, fragrances, sunscreens, and photo allergens, which are substances that cause a reaction when exposed to light.
Risk Factors and Frequency for Allergic Contact Dermatitis
Allergic contact dermatitis is a skin condition that causes inflammation and is frequently found in the general public. In fact, it’s the leading skin disease people get from their jobs. Though this issue affects everyone, it’s seen more often in women than in men. Moreover, older people with this condition often have a connection with skin medicines they use.
Signs and Symptoms of Allergic Contact Dermatitis
When diagnosing allergic contact dermatitis, doctors usually take a detailed history of a patient’s work, hobbies, medications used, lifestyle, and any use of fragrances and perfumes.
Allergic contact dermatitis can appear in two forms: acute and chronic. Symptoms of the acute form often include redness, rashes or blisters. While it usually appears as a localized rash, commonly on the hands or face, it can sometimes affect a larger area. For instance, products like shampoo or body wash that rinse off can touch many parts of the body and cause a more widespread rash. Moreover, if a person ingests an allergen, they can experience a broad skin reaction. Chronic allergic contact dermatitis usually presents with thickened skin, deep cracks, and flaky skin.
Testing for Allergic Contact Dermatitis
In order to effectively evaluate allergic contact dermatitis, a condition where your skin becomes irritated or inflamed due to an allergic reaction, doctors generally conduct a thorough study of your symptoms and medical history. The way the rash appears and where it is located on your body can often give good hints about what might have caused it.
The most reliable method to confirm if you have allergic contact dermatitis is through patch testing. In this test, small amounts of potential allergens are applied to your skin through adhesive patches. This test is used when doctors suspect you have allergic contact dermatitis, especially if your symptoms keep coming back. Patch testing can help identify what’s causing the allergic reaction, so that you can avoid it in the future.
While patch testing is pretty straightforward, it’s important to note that using this test too often might lead to higher medical costs. If the results from this test aren’t clear, a skin biopsy may be needed. This is a procedure where a small sample of your skin is removed for further testing.
The doctor will also want to rule out that a type of skin infection caused by a fungus, known as tinea, isn’t causing the rash. This condition is often mistaken for dermatitis due to their similar symptoms.
Treatment Options for Allergic Contact Dermatitis
The only surefire way to treat Allergic Contact Dermatitis (ACD), a type of skin inflammation caused by an allergy, is to identify and remove what’s causing the allergic reaction. Everyone with suspected or confirmed ACD should be aware of this. If the allergies affect less than 20% of your body, applying steroid creams or lotions may help. If more than 20% of your body is affected, you may need to take steroid pills.
If the rash occurs on sensitive skin areas like your eyelids or under folds of skin, other treatments such as calcineurin inhibitors and PDE4 inhibitors, two types of skin medication, might also work. The key treatment remains to identify what’s causing the allergy and to stay away from it to prevent symptoms from coming back. Other symptom relief tactics include antihistamines, a type of medication that fights allergies, topical hydrocortisone, or creams that treat skin irritation, and soothing cool water soaks. Avoid puncturing any blisters as this can lead to infection. Keeping your skin moisturized is also helpful.
For the really tough cases, medications like tacrolimus that modify the immune response may help. Some people may also benefit from light therapy, where you’re exposed to ultraviolet light in a controlled manner. In extremely severe cases, patients might need to use medications like mycophenolate, which suppresses the immune system.
If you’re dealing with chronic or difficult-to-treat ACD, a patch test can help determine what’s causing the allergies. This test involves putting small amounts of potential allergens on your skin using patches. Patch testing requires the selection of the right allergenic chemicals, a positive reaction to relevant allergens, and after-test discussions on the results. The American Contact Dermatitis Society provides a program for managing contact allergens, which helps in compiling a “safe list” of products that do not contain the patient’s identified allergens. If complete avoidance of these allergens is not possible, you may need to take systemic therapy, meaning medicine that affects the whole body.
What else can Allergic Contact Dermatitis be?
When someone presents with skin symptoms, it can be challenging for doctors to pinpoint the exact condition. This is because allergic contact dermatitis looks a lot like other skin issues such as irritant contact dermatitis and atopic dermatitis. There are also many other skin conditions that have similar symptoms, including:
- Drug eruptions (rashes as a reaction to medication)
- Scabies (a highly contagious skin infestation caused by tiny mites)
- Bullous pemphigoid (a rare skin condition that causes large, fluid-filled blisters)
- Urticaria (also known as hives)
- Psoriasis (a skin condition that causes itchy or sore patches of thick, red skin with silvery scales)
- Seborrheic dermatitis (a common skin disease that causes redness, scaly patches, and dandruff)
- Periorificial dermatitis (a facial skin disorder characterized by red, bumpy rashes around the mouth, nose, eyes, and sometimes on the genitalia)
- Rosacea (a chronic, acne-like condition in adults)
What to expect with Allergic Contact Dermatitis
Allergies can be a lifelong condition for those affected. The best course of action is to steer clear of whatever triggers the allergy. The main goal of allergy treatment is to manage the body’s inflammation response to the allergen.
The longer a person has an allergy, the more time it may take for it to clear up. This is why it’s important to consult with a doctor to understand the severity of an allergy and the best ways to manage it.
Possible Complications When Diagnosed with Allergic Contact Dermatitis
Complications related to allergic contact dermatitis (ACD), a common skin condition, primarily stem from the body’s inflammatory response. This inflammation usually goes away once the offending allergen, or trigger, is removed. If the allergen is taken into the body, it can result in a widespread skin inflammation, but this isn’t typically considered a medical emergency from a skin health perspective.
Common Complications :
- Inflammation caused by the body’s reaction
- Widespread skin inflammation if the allergen is taken into the body
Preventing Allergic Contact Dermatitis
In simple terms, teaching patients about a skin condition known as allergic contact dermatitis (ACD), or an allergic skin rash, is about helping them recognize what they’re allergic to. Once they know their triggers, patients can then learn new habits that will lessen the inflammation or redness and swelling caused by this condition.
For instance, some jobs require folks to regularly use rubber gloves. For these individuals, it’s crucial that they know if they have a natural rubber allergy, and if so, they should choose gloves made from a different material. These materials could be thiurams, carbamates, or mercapto compounds, and it’s important those are ones they don’t have allergic reactions to.
Moreover, some patients have found that a diet low in nickel and other minerals can help improve symptoms of their skin condition.