Atopic dermatitis is a chronic skin condition that causes dry, itchy skin. It’s one of the most common forms of eczema. Another type is contact dermatitis. A localized rash occurs when the skin makes contact with substances containing an allergen. This could be caused by a new skincare product or laundry detergent.
There are three different types of contact dermatitis:
- allergic contact dermatitis
- irritant contact dermatitis
- photocontact dermatitis
While both atopic and contact dermatitis are types of eczema that present very similar symptoms, they have different causes.
Keep reading to learn more ways to tell atopic and contact dermatitis apart.
Atopic dermatitis is usually inherited, while contact dermatitis is the result of coming in contact with an external factor. People have different allergens, but the most common types are included in the list below.
|Atopic dermatitis causes||Contact dermatitis causes|
|Family history of eczema||Soaps|
|Personal history of eczema||Shampoos|
|Hay fever||Citrus fruit|
|Sweat||Poison ivy, poison oak, and poison sumac|
|Long, hot baths or showers||Hair dyes|
|Frequent exposure to chemicals|
The symptoms of atopic and contact dermatitis are quite similar. They may both have a huge impact on a person’s quality of life.
Symptoms of both atopic and contact dermatitis include:
The location of symptoms is often different. Cosmetic Dermatologist Dr. Michele Green explains that atopic dermatitis classically develops in the folds of the arms and knees, and around the eyes.
On the other hand, contact dermatitis can appear anywhere on the skin. “The location of the rash is a clue to the allergen,” she says.
Both conditions can go through eczema’s three stages.
Acute eczema phase
In this first stage, the skin is triggered by an irritant. This causes red, pruritic skin that oozes.
“The more you scratch it, the worse the rash gets and does not allow it to heal and can get secondarily infected,” Green says.
Certain symptom differences happen during this stage. For example, small blisters of vesicles are likely to develop with contact dermatitis.
“This is upon exposure to the allergen, which often weep,” Green says.
This skin condition is the most common form of eczema. It’s also the most severe and chronic. Those with eczema typically experience extremely dry, itchy skin.
Because atopic dermatitis is inherited, those who have a type of family history are more predisposed to developing eczema.
Research shows that identical twins are 75 percent more likely to develop atopic dermatitis if one twin is affected.
Contact dermatitis causes a severe itchy rash and reddened, inflamed skin.
The rash is often in the shape of an irritant, according to Susan Massick, MD, Associate Clinical Professor of Dermatology and board-certified dermatologist at The Ohio State University Wexner Medical Center.
For example, you would notice linear lines if you came into contact with a poison ivy plant.
Massick says that the onset of symptoms usually appears within 1 to 2 days of exposure and can last up to 2 to 4 weeks. During this time, the rash may blister with drainage, as well as crust.
Sub-acute eczema phase
This is the transitional phase, also known as the healing stage. Because there is no cure for eczema, the condition can still have flareups if left untreated.
Chronic eczema phase
The result of ongoing scratching can cause the skin to develop scaly patches that are discolored (often brown). The skin also becomes thickened and leathery. It’s common in children, who may not be able to resist scratching or picking at it.
You can have both atopic and contact dermatitis at the same time.
Dr. Alan J. Parks says that people with atopic dermatitis are even more likely to develop contact dermatitis. This is often the result of someone with underlying atopic dermatitis being exposed to allergens that trigger contact dermatitis.
“Contact allergies are commonly seen in atopic dermatitis, but not all people with contact allergies will have underlying AD [atopic dermatitis],” he says.
Many factors help doctors diagnosis atopic and contact dermatitis. Doctors will look at the location of the rash, its appearance, and a review of your medical history.
Typically, though, a visual test is all that’s needed.
When further testing is required, doctors may perform a biopsy. This should be performed during the acute stage of eczema because similar features make it difficult to differentiate between the two conditions.
Below are additional factors doctors will take into consideration when diagnosing:
Atopic dermatitis is usually found on the insides of elbows and backs of knees. Around the eyes is another common area.
Contact dermatitis can appear anywhere on the skin. Common areas include the hands and face. If you have a nickel allergy from your watch, for example, the rash will be located on your wrist.
You can even transmit allergic contact dermatitis onto sensitive areas, such as the eyelids and genitals.
Atopic dermatitis commonly affects children.
Research has found that 50 percent of people with atopic dermatitis develop symptoms within the first year of their life.
While some adults experience the condition, the majority will grow out of it once they reach adolescence.
Meanwhile, contact dermatitis can affect any age, Massick says. That’s because it’s an allergic and hypersensitivity reaction. Many young children are allergic to nickel, while people over the age of 70 commonly experience contact dermatitis from topical antibiotics.
Your profession can also come into play. Hairdressers, for instance, may experience contact dermatitis due to their regular exposure to chemicals.
Be prepared for your doctor to ask several questions about your medical history. According to Dr. Massick, questions you might hear include:
- How long has this been going on?
- Have you come in contact to hair, skincare, or food products, have a history of asthma or seasonal allergies, or have added stress?
- What measures seem to help?
- What’s the frequency of symptoms?
- Have you started using any new products?
- Have you started a new medication, including vitamin supplements?
- What has changed about your daily routine?
Patch testing is allergy testing that’s specifically used for contact allergies.
Small patches of specific allergens are applied directly to the skin, left on for 24 to 72 hours (the area needs to stay dry), removed and then skin assessed for any skin reaction,” Massick says.
Treatment for atopic and contact dermatitis is relativity similar. Both conditions can be treated with topical or oral medications to ease and prevent symptoms.
Additional treatments to try include:
- moisturizing regularly to prevent dry skin
- using gentle skin products, such as mild soap
- avoiding harsh chemicals or products with fragrance or perfume
- avoiding triggers like extreme heat or foods you’re allergic to
- managing stress
- taking antibiotics in the event of an infection
- keeping showers or baths brief
- limiting use of hot water while bathing
In some cases, treatment for contact dermatitis isn’t necessary. It may clear up on its own.
“Atopic dermatitis tends to be more chronic and there are biologic medications that can be used, whereas contact dermatitis is more acute and eventually would resolve even without treatment,” Parks says.
In other words, prevention with contact dermatitis is key.
Identifying the cause of the allergy with contact dermatitis is important to avoid that trigger in the future. According to Dr. Massick, you want to focus on:
- avoiding exposure as much as possible
- washing your skin after exposure
- oral antihistamines (if needed)
- topical steroids for immediate symptomatic relief (you may need oral or systemic steroids depending on severity of the allergic reaction)
You will want to see a dermatologist if you experience the following.
For atopic dermatitis:
- skin is severely inflamed or itchy
- symptoms are affecting daily activities or are interfering with sleep at night
- skin is infected and showing signs of scabbing and crusting, pus, or drainage
- symptoms aren’t improving despite treatment
For contact dermatitis:
All of the symptoms above and:
- rash becomes painful
- rash is spreading with no known cause
You will want to seek immediate medical attention if you experience any of the following:
Go to the nearest emergency room or call 911 if you experience any of the following symptoms of a severe allergic reaction:
- severe infection with pus
- severe blistering
- difficulty breathing
- difficulty swallowing
If you don’t already have a dermatologist, the Healthline FindCare tool can help you connect to physicians in your area.
While atopic dermatitis is usually inherited, contact dermatitis is the result of external stimuli. There are many similarities involving symptoms, diagnosis, and treatment.
See a dermatologist if your symptoms do not improve.