‘Vague’ symptoms, poor communication lead to psoriatic arthritis misdiagnoses

AUSTIN, Texas — Communication and awareness of the myriad disease domains are essential to preventing a misdiagnosis of psoriatic arthritis, according to a presenter at the 2023 Rheumatology Nurses Society annual conference.

“Diagnosis of psoriatic arthritis is clinical,” Rebekah Garrard, RN, MSN, FNP-C, a nurse practitioner at Lafayette Arthritis & Endocrine Clinic, in Louisiana, told attendees. “Accuracy often depends on the knowledge and skills of the clinician.”

There are several reasons why PsA misdiagnoses or delayed diagnoses occur, according to Garrard. One is that although 14% to 30% of patients with psoriasis go on to develop PsA, 10% will not demonstrate any psoriasis symptoms before PsA develops.

“These are the patients that get overlooked,” Garrard said.

Another issue is that it can take up to 10 years for PsA to develop after a psoriasis diagnosis. This can lead to diagnostic delays that are commonly longer in women than men, but occur across genders.

“Patients do not know what psoriasis is,” Garrard said. “They see it on TV commercials, and patients have these big plaques all over. They do not realize it can be less severe. They think it is eczema.”

Although patients know of these plaques, clinicians may miss guttate, inverse or pustular psoriasis as an indicator of PsA. When they have these less severe skin manifestations, patients may begin self-medicating “because it’s not that bad,” Garrard said.

Meanwhile, other symptoms of PsA, like fatigue and stiffness, can be “vague,” she added.

“Symptoms can go for a long time before they get worse,” Garrard said.

Radiographic evidence can also be unreliable.

“It is also important who is reading their X-rays,” Garrard said, noting that non-rheumatology providers may not be able to spot the axial or structural manifestations of PsA.

Additionally, several conditions can mimic PsA, including osteoarthritis, rheumatoid arthritis, gout, axial spondyloarthritis and plantar fasciitis, contributing to misdiagnoses.

“People are also often misdiagnosed with fibromyalgia,” Garrard said.

Further complicating factors include the presence of anxiety and depression, which can lead clinicians to attribute their symptoms to “psychosomatic disorders,” she added.

Although nail lesions, dactylitis and tenosynovitis are commonly present in PsA, these domains are frequently overlooked, according to Garrard.

“Eighty to 90% of PsA patients have nail lesions, but nobody is looking at them,” she said.

Beyond clinical findings, another reason some patients with PsA are overlooked is because tests like hyperuricemia, HLA-B27, HLA-C*06 and others are not reliable or clinically feasible.

“We really do not have any great lab findings for psoriatic arthritis,” Garrard said.

Additionally, C-reactive protein, erythrocyte sedimentation rate, rheumatoid factor, cyclic citrullinated peptide and antinuclear antibodies (ANA) often are “misleading,” according to Garrard.

“These are not great predictors for us,” she said.

To prevent a missed PsA diagnosis, it is important to touch the patient to determine the extent of pain and swelling.

“Patients will come to me and say their other doctor did not touch them,” Garrard said.

However, and perhaps most importantly, simply talking and listening to the patient can be hugely beneficial. Specifically, using common language like “itching” or “rash” can be more helpful than asking, “Do you have psoriasis?”

“We have to talk to our patients,” Garrard said. “We have to use their language.”