Many patients with rheumatic disease also suffer from skin disease, with diagnoses and treatments often overlapping or contraindicating each other. Some clinicians are more comfortable than others at treating both conditions and clearly explaining situations to their patients.
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“In my opinion, rheumatologists, often, are more comfortable, or willing, to deal with all the other comorbidities of their patients’ diseases. We are much more inclined to be a primary care provider,” says Joseph F. Merola, MD, MMSc, an internist, rheumatologist, dermatologist, director of the Clinical Unit for Research Innovation and Trials (dermatology), associate program director of the Combined Medicine-Dermatology Residency Program, and co-director of the Center for Skin and Related Musculoskeletal Diseases at Brigham and Women’s Hospital in Boston.
Dr. Merola, an assistant professor at Harvard Medical School, and member of the medical board of the National Psoriasis Foundation, spoke with The Rheumatologist about how rheumatologists and dermatologists can best work together for the good of their shared patients.
Improve Screening for Inflammatory Arthritis & Psoriatic Arthritis
As many as 30% of psoriasis patients have psoriatic arthritis, and as many as 41% of patients with psoriasis have a new diagnosis of previously undiagnosed psoriatic arthritis.1 Dr. Merola says those levels of prevalence show that both rheumatologists and dermatologists need to be educated on how to properly screen for the conditions.
“[Screening] is often tough for dermatologists, because they don’t feel comfortable doing a joint exam or asking questions about inflammatory arthritis,” he says. However, “rheumatologists will often get referrals from dermatologists for inflammatory/psoriatic arthritis in patients with osteoarthritis or fibromyalgia.”
Dr. Merola suggests dermatologists use a validated questionnaire, such as the Psoriatic Arthritis Screening and Evaluation (PASE), Psoriasis Epidemiology Screening Tool (PEST) or Toronto Psoriatic Arthritis Screening (ToPAS) survey. None is a perfect questionnaire, he says, but “all have reasonable sensitivity and specificity” for psoriatic arthritis.
“If [a dermatology] patient screens positive [using those questionnaires], they should be referred to a rheumatologist,” he says, noting early diagnosis is beneficial. “[Rheumatologists] can then get these patients to appropriate therapy more quickly, because we treat psoriatic disease with arthritis potentially differently than disease without arthritis.”
Ensure Appropriate Ordering, Interpretation of Lab Tests
Rheumatologists often get referrals based on positive antinuclear antibody (ANA) tests, many of which are false positives that trip up the referring dermatologist. These referrals for connective tissue disease or lupus often frighten patients, and Dr. Merola says rheumatologists spend “a lot of time reassuring patients” that the positive result is “not clinically meaningful.”
“I think there is a lot of testing without appropriate clinical context or pre-test concern for disease,” he says. “It is all about clinical context [and titer]. There are lots of other diseases that cause a positive ANA that are not lupus. We need to get the message out to primary care and dermatologists: A positive ANA does not automatically [equate to] systemic connective tissue disease. [Dermatologists] need to be really judicious in ordering ANAs, unless the clinical suspicion is reasonable.”
Another common mistake: Ordering a beta-2 microglobulin (B2M) test when “dermatologists really mean to order a beta-2 glycoprotein 1 antibody test,” Dr. Merola adds. “It’s nuanced, but it is something a rheumatologist would know. The B2M is a totally unrelated test, and ordering the B2M is a common mistake when evaluating antiphospholipid antibodies in the dermatology patient presenting with vasculopathy.”
Identify & Treat Skin Rashes Caused by Anti-TNF Inhibitors
Anti-TNF drugs can actually cause the skin rashes they are meant to treat, which can be confusing and lead to unnecessary changes in otherwise successful therapy plans.2 Drug-induced psoriasiform dermatitis is one not-so-uncommon example. Dr. Merola says rheumatologists should also be familiar with less-common skin rashes, including a type of anti-TNF induced skin lupus (subacute cutaneous lupus) and dermatomyositis.
“It is important for rheumatologists to recognize those [conditions] and feel comfortable” treating them, Dr. Merola says. “And it is super important for dermatologists to understand that a large majority of these patients, who are on these anti-TNF drugs for an extended period, can actually develop a positive ANA and other abnormal rheumatologic lab testing in the absence of any concerning systemic disease.”
Recognize Psoriasis Is More Than a Cosmetic Issue
Putting on his dermatologist hat, Dr. Merola says some rheumatologists don’t appreciate how psoriasis affects quality of life. Focused on controlling the joint disease, “they sometimes overlook or underplay the patients’ skin disease,” he says.
“A whole host of studies show the quality-of-life impact of the skin component is tremendous, in some cases even more so than the joint disease in patients who have both joint and skin disease,” Dr. Merola explains. “To drive home the point, one study demonstrated that up to 10% of younger patients may even have contemplated suicide due to their psoriasis, which is an extreme example to underscore how impactful [psoriasis] is on quality of life.”3
He suggests taking exam time to identify inverse (intertriginous) psoriasis, often found in the armpits, gluteal cleft of the buttocks, the groin or other body-fold areas.
“It’s really important,” he says. “These are potentially associated with increased risk of psoriatic arthritis. It is under-recognized in both the rheumatology and dermatology communities.”
Treat Rheumatic & Skin Disease Globally
Access is a global issue, and many rheumatology patients who wait six months for an appointment also have dermatology issues.
“It can be a tremendous help if the rheumatologist is also comfortable treating any residual skin disease,” Dr. Merola says. “Often, they are using drugs that will treat both. If there is still some leftover skin disease, for example, rheumatologists should be comfortable prescribing appropriate topical steroids. … And don’t prescribe something that is too weak or give a very small tube to a patient who needs a large quantity of medication.”
Richard Quinn is a freelance writer in New Jersey.
- Kurd SK, Gelfand, JM. The prevalence of previously diagnosed and undiagnosed psoriasis in US adults: Results from NHANES 2003-2004. J Am Acad Dermatol. 2009;60(2):218–224.
- Cozzani E, Larosa M, Parodi A. Skin manifestations associated with anti TNF-α therapy. Clin Dermatology. 2013;2(2):67–71.
- Lee YW, Park EJ, Kwon IH, Kim KH, Kim KJ. Impact of psoriasis on quality of life: relationship between clinical response to therapy and change in health-related quality of life. Ann Dermatology. 2010 Nov;22(4):389–396. doi: 10.5021/ad.2010.22.4.389. Epub 2010 Nov 5.