Dr. Raj Chovatiya discusses the distinctions between itch and pain sensations and the treatment of pain as a symptom of inflammatory skin disease.
Raj Chovatiya, MD, PhD, is Assistant Professor and Director of Center for Eczema and Itch in the Department of Dermatology at Northwestern University Feinberg School of Medicine.
“We know that you don’t necessarily have to have overt tissue damage to experience pain,” said Raj Chovatiya, MD, PhD, who presented “Skin Pain. Is this a real phenomenon?” at the Diversity in Dermatology 2022 Conference.
There are two types of pain, according to Dr. Chovatiya: nociceptive and neuropathic.
“Nociceptive is the pain we think about when there’s injury [and/or] inflammation, such as following surgery or a sports injury. In the case of neuropathic [pain], this is when there’s nervous system dysfunction. You can see this type of pain in the absence of tissue injury, such as with diabetic neuropathy or post herpetic neuralgia.”
It’s an important distinction to make, according to Dr. Chovatiya, because while pain in general is designed to signal caution in potentially harmful situations, that’s not always the case.
“We can use inflammatory skin diseases to understand this concept a little better. Atopic dermatitis is a nice model disease from that standpoint because skin pain is arguably as important as itch for many patients.”
Yet, historically, dermatologists don’t give skin pain the same level of consideration, according to Dr. Chovatiya.
“Skin pain in atopic dermatitis is not just related to just the scratching that comes from itch, but it’s a sensation in its own right.”
Itch vs. Pain
According to Dr. Chovatiya, itch and pain likely have neurologic pathways that are distinct but also overlap, causing a blur between the two sensations.
“…if we take it back to the early days in neuroscience, people thought that itch was just a milder sensation of pain and pain was the more severe sensation. Obviously, that doesn’t make much sense. If you have mild pain in your gastrointestinal system, for example, you perceive this as abdominal pain and not itch.”
However, when patients with an inflammatory skin disease like atopic dermatitis describe their skin pain, they use the descriptors like “stinging,” “burning,” and “tingling,” which are also often used to describe neuropathic itch, said Dr. Chovatiya.
“We haven’t fully teased this apart, but bottom line, skin pain matters to patients right alongside itch.”
Pain is one of the clinical domains you should think and ask about for any disease, said Dr. Chovatiya.
“I think it’s important to characterize symptoms right alongside the severity of lesions, especially in a heterogenous disease like atopic dermatitis. And even when it comes to symptoms, patients may have a low burden of itch but a high burden of skin pain. A great example of this is hand eczema, where skin pain can drive many negative aspects of quality of life for patients—they can’t work, they can’t wash their hands, they can’t do their day-to-day activities.”
In fact, pain could be the deciding factor in stepping up to advanced therapy, he said.
“Conventional measures like body surface area, lesional severity, or even itch severity are going to completely miss this point.”
A Question of Analgesia
With a greater focus on skin pain, said Dr. Chovatiya, the question becomes, do your patients need more (or targeted) pain relief?
“[It’s] probably a mixed picture without clear answers for the moment, but we are beginning to understand more.”
While international studies have suggested that patients being treated for atopic dermatitis may not need supplementary analgesia, other U.S.-based studies suggest that as many as half purchase over-the-counter analgesics to manage the pain on their own, suggesting an undertreated symptom, said Dr. Chovatiya.
“However, emerging data with targeted systemic therapy—dupilumab is a great example—has suggested that this may be sufficient to reduce skin pain when you look at baseline and post-treatment pain severity.”
These findings underscore the need to pursue a line of questioning related to skin pain, said Dr. Chovatiya.
“You’re starting to see these measures in clinical trials as well when it comes to atopic dermatitis.”
Skin pain is also an important consideration with other diseases, including psoriasis and hidradenitis suppurativa, he said.
“At minimum in the clinic, it’s worth sneaking in a couple questions. Do you have any pain in your skin? Tell me about how bad it is on a scale of zero to 10? This can instantly give you a lot of valuable information.”
The Skin Pain Phenomenon
Whether it’s atopic dermatitis, psoriasis, hidradenitis suppurativa, take the time to ask patients about their signs, symptoms, and quality of life to create the comprehensive picture necessary for disease management, said Dr. Chovatiya.
“Study after study suggests that focusing on any one [clinical domain] does not capture the heterogeneity of these diseases, and to make the best judgment [for therapy], it behooves you to measure disease burden across all of these domains.”
Disclosures: Dr. Chovatiya has served as an advisory board member, consultant, and/or investigator for Abbvie, Arcutis, Arena, Beiersdorf, Bristol Myers Squibb, Dermavant, EPI Health, Incyte, National Eczema Association, Pfizer, Regeneron, Sanofi, and UCB, and speaker for Abbvie, Eli Lilly, Incyte, Pfizer, Regeneron, Sanofi, and UCB.
