What Is the Difference between Eczema and Psoriasis? Dr. Candrice Heath MD, FAAD, FAAP explains

When Cassandra was growing up, people would tease her because she had psoriasis of the scalp. And even now, when Cassandra gets really stressed, she’ll have psoriasis and eczema flares too. Things like psoriasis and eczema can truly impact the quality of someone’s life. So, Cassandra wanted to speak with experts and ask questions about what truly happens with the skin. Can eczema and psoriasis cause the hair to fall out? In this blog, we’ll chat with a triple-board certified dermatologist who has expertise in scalp conditions. Dr. Candrice is one of Cassandra’s favorite internet doctors, and she's agreed to answer some questions about the different conditions of the scalp. She also speaks about what her patients go through, what works for a flaky, dry scalp, and what doesn’t. 

Dr. Candrice says, “When something occurs on the outside, it truly affects you in a different and profound way. For that reason,  I not only desire to help people with their skin disorders, but I also want to be able to lift their confidence.” 

What is the difference between psoriasis and eczema?

Dr. Candrice: These are both chronic conditions that can affect the skin. Eczema is an umbrella term.  In the medical field, eczema houses a lot of conditions, whether it's atopic dermatitis, contact dermatitis, or seborrheic dermatitis. Atopic dermatitis is a special eczema that happens in people who may be prone to asthma or seasonal allergies. There’s also contact dermatitis which is when someone develops a rash upon something coming into contact with their skin. But, for the purpose of this conversation, we’re going to focus on eczema as atopic dermatitis which is more of an inherited condition that produces dry, itchy skin. It can start very early, and a lot of my patients come in as newborns or toddlers. It can persist, but it also starts to affect our bodies in different ways as we get older. Thankfully, a lot of patients outgrow their childhood eczema, but sometimes that does not occur, and people have issues with their skin that persist into adulthood. 

On the other hand, psoriasis is also a chronic skin condition. Psoriasis can affect any area of the body. Psoriasis loves to make these thick, scaly rashes on places like the elbows, knees, and scalp. They make these thick plaques that continue to stay there. The scalp is a common location for both psoriasis and eczema. We now know a lot about psoriasis or way more than we used to. Sometimes psoriasis can actually be associated with arthritis or joint pains. Psoriasis can also be associated with diabetes, high blood pressure, and high cholesterol. It is a skin disease, but as dermatologists, we’re supposed to look beyond the skin disease and ask, “What else can affect my patient who has this skin disorder?”

How do psoriasis and eczema affect hair loss and hair growth?

When anything that is going on with the scalp involves scale, it can be embarrassing. So, the first thing people do when they wake up in the morning is try to camouflage the scales. They may shampoo it and apply medications. But oftentimes, with both seborrheic dermatitis and psoriasis, people try to pick the scales away. However, when you pick off the scale, you can rip out hair as well. This removal of scale is often a huge part of people’s haircare routine. But, if you are manually scraping the scale upon having psoriasis, a special occurrence called the Koebner phenomenon will begin to take place. This is basically when the skin says, “The more you traumatize me, the more I’m going to protect myself and build more skin.” So, if you have psoriasis of the scalp, and you’ve spent a significant amount of time removing all the scales and going through your wash day routine, this explains why the scales are still there. It can look great for two days, and then, the scale comes back.  So, when the scale reclaims its position, that is what the Koebner phenomenon is. The more you traumatize it, the thicker it becomes. So, we have to be strategic about addressing psoriasis of the scalp to keep the patient happy and confident, but we also have to attack the underlying issues, which in most cases, is psoriasis. 

What ingredients can help psoriasis of the scalp?

Let’s talk about ingredients that can keep scales to a minimum. One example is something that contains salicylic acid. That’s great. We may think about this ingredient as something that helps with acne, but it can also help bring those thick scales down to a minimum. But, of course, they’re might be situations that cannot be controlled by using OTC medications.

For both seborrheic dermatitis and psoriasis, tar-containing products, and topical corticosteroids can be helpful. For seborrheic dermatitis,  topical ketoconazole, pyrrhotine zinc, and selenium sulfide are helpful. For psoriasis, topical calcipotriene helps with scale thickness.Calcipotriene is a vitamin D derivative that helps to slow thick plaque regrowth that can happen on the scalp of those who have psoriasis. 

What is a doctor’s appointment for a psoriasis patient like?

First, I examine the scalp and make a diagnosis about what they have, but it often includes prescribing topical medications that can help reduce inflammation. If your doctor is considering a diagnosis of psoriasis, the dermatologist may ask to see your knees, elbows, or other areas. If they are considering a diagnosis of seborrheic dermatitis, they may check the ears, sides of the nose, eyebrows, and chest.