Do you have dry, itchy skin that just doesn’t seem to get better, even after trying different creams and lotions? You may have eczema or psoriasis, which look very similar to one another. Your primary care doctor or a dermatologist (skin specialist) can help make a diagnosis. Fortunately, eczema and psoriasis share similar treatments. Once you get the right diagnosis, you can be put on the best treatment plan.
What Causes Eczema?
Eczema is caused by an overactive immune system that damages your skin barrier.1 Eczema is usually triggered by allergens or irritants that cause skin inflammation. As a result, your skin becomes dry, red, and itchy. Many people with eczema have environmental allergies to pollen or dust — they can also have food allergies.2
Your genes also play a role in developing eczema. Doctors and researchers believe that the filaggrin gene plays a role in eczema.1 This gene creates the filaggrin protein, which helps your skin hold onto moisture. Changes in the filaggrin gene can be passed down through family members. If you have a parent or sibling with eczema, you’re more likely to develop it yourself.
What Causes Psoriasis?
In contrast with eczema, psoriasis is an autoimmune condition.3 Your immune system mistakes your healthy skin cells for foreign invaders and attacks them. This creates inflammation that causes your skin cells to grow very fast. Normally, it takes 30 days for your body to replace old skin cells with new ones. The inflammation from psoriasis speeds this process up, so it only takes a few days.
What Are the Symptoms of Eczema?
To the average person, eczema and psoriasis symptoms can look extremely similar to one another. They also tend to develop in the same places on the body — the elbows, knees, and torso. However, your doctor or dermatologist will be able to tell them apart through a few key differences.
Common eczema symptoms include:4-6
- Dry or cracked skin
- Red patches or rashes (on lighter skin) or dark brown, gray, or purple rashes (on darker skin)
- Bumpy skin rashes on people with darker skin tones
- Sensitive or irritated skin from scratching
- Weeping or clear fluid oozing from the skin
- Dark skin underneath or around the eyes
- Thickened patches of skin
Eczema typically develops during childhood before the age of 5.4 Some people have their symptoms continue into adulthood. Others may experience flares or worsening of symptoms over their lifetime.
Areas of your body where you’re more likely to find eczema include the insides of your elbows, the backs of your knees, and the back of your neck. In some cases, you may also notice itchy rashes on the palms of your hands and the bottoms of your feet.7
What Are the Symptoms of Psoriasis?
There are five types of psoriasis, and each causes its own set of symptoms.8 For the sake of this article, we’ll talk about plaque psoriasis — the most common type.
Plaque psoriasis is associated with raised areas of thickened skin known as plaques or scales.9 Psoriasis makes your skin cells grow much faster than normal. As a result, the skin cells build up and create thick plaques. On lighter skin, plaques are red. For those with darker skin, plaques may be dark brown, purple, or gray.
Psoriasis plaques are dry and can crack open into what are known as fissures and bleed. They can also have a white or silvery layer of dead skin on top. Some people say that their plaques are itchy and can become painful or irritated.
Psoriasis can affect nearly any part of your body — including your face, scalp, hands, feet, and genitals.8 Some types of psoriasis are more likely to appear in certain body areas compared to others. For example, plaque psoriasis tends to form on the elbows, knees, torso, and scalp.10 On the other hand, inverse psoriasis causes red rashes that affect the skin folds around the genitals, breasts, and armpits.11
How Is Eczema Diagnosed?
Skin conditions like eczema and psoriasis are diagnosed using the results from your medical history, a physical exam, and a few tests.
Your primary care doctor or dermatologist may start by asking you:12
- Where you are experiencing skin problems
- How long your symptoms have been happening
- Whether there are any triggers that make your symptoms worse
- Whether you have any seasonal, environmental, or food allergies
- Whether anyone in your family has eczema or psoriasis
They’ll also take a closer look at your skin and note what your rash looks like. They may ask if it’s itchy or painful.
If your doctor thinks you also have skin allergies (allergic contact dermatitis), they may order patch testing. During this test, your doctor will apply small amounts of different allergens to your skin to see if you develop a red, raised bump under any of the allergens. Your allergies may be causing your eczema symptoms.
How Is Psoriasis Diagnosed?
To diagnose psoriasis, your doctor will also use your medical history and physical exam results. They may ask questions about:13,14
- Where your symptoms are
- When your symptoms first started
- Whether areas of your skin are red, itchy, or painful
- Whether anyone in your family has a history of psoriasis
- Whether you have any underlying health conditions, like human immunodeficiency virus (HIV) or acquired immunodeficiency syndrome (AIDS), which raise your risk of psoriasis
Since eczema and psoriasis look like one another, your doctor may perform a skin biopsy.13 During this procedure, they’ll numb an area of affected skin and take a small tissue sample. The sample is sent to a laboratory and looked at under a microscope. The biopsy results can tell your doctor whether you have psoriasis or another skin condition.