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Diagnosis Detective: Deciphering dermatologic symptoms of rheumatic diseases
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Many rheumatic diseases – including systemic lupus erythematous, scleroderma and the various forms of psoriasis – present with a multitude of dermatologic symptoms that clinicians can easily confuse with other conditions.
According to M. Elaine Husni, MD, MPH, vice chair of the department of rheumatic and immunologic diseases, and director of the Arthritis Center at the Cleveland Clinic, rheumatologists must think and work like a detective to properly examine a patient’s symptoms and determine the proper diagnosis.
“The most challenging part for rheumatologists regarding these dermatologic symptoms — because we are not looking at skin complaints all the time like a dermatologist would — are the really hidden psoriasis types, for example in the ear and on the scalp,” Husni told Healio Rheumatology. “Unless you lift up the hair, you might never notice that the patients have psoriasis; sometimes you have to play detective and think more objectively to find the diagnosis.”
It also helps, she noted, to have a great partner in a dermatologist who can lend their expertise during physical exams, and advise on possible treatments.
“I think when you have diseases that affect multiple organs, it is important to collaborate with other specialists to improve patient outcomes,” Husni added. “This includes having someone who specializes in skin conditions to help you with the exam and come up with a treatment regimen.”
Skin-deep signs
Anthony P. Fernandez, MD, PhD, staff physician at the Comprehensive Lupus Clinic, and the departments of dermatology and pathology at the Cleveland Clinic, often works with rheumatologists, including Husni, to assist with examinations and develop treatment plans, he said.
According to Fernandez, that can often include advising on the telltale dermatologic signs of various rheumatic conditions.
“With psoriasis, the most common subtype is plaque psoriasis, which typically has well-demarcated plaques and lesions, commonly on the elbows and knees, and scalp and gluteal cleft,” he said. “Dermatomyositis is another one that we see at a tertiary care center relatively frequently, with symptoms including pink papules that tend to occur on the hands and overlying the interphalangeal joint.”
In diagnosing scleroderma, physicians should look for Raynaud’s phenomenon in the patient, paying special attention to examining their nailfold capillaries to see if they are visible, as that can be a secondary sign of Raynaud’s, he told Healio Rheumatology. Fernandez added that swelling of the hands and any firmness to the skin can also be symptoms of scleroderma.
Another condition with meaningful dermatologic symptoms is vasculitis, which presents with some non-blanching red papules that occur most commonly on the legs, he added.
Lupus presents with many cutaneous symptoms, according to Fernandez, but the most common is systemic lupus’ hallmark butterfly rash that occurs on the face.
“However, there are many other types,” he said. “Discoid lupus can occur in the setting of systemic lupus, and that usually presents with scarring in the trophic areas that lack pigment.”
According to Husni, skin manifestations are commonly seen in patients with autoimmune diseases, particularly psoriasis and psoriatic arthritis.
“Psoriasis comes in many different forms which makes it a bit challenging,” she said. “There are five different forms.”
Although the most common is plaque psoriasis, she noted that one-third of patients can go on to develop psoriatic arthritis, in which case they would need to go see a rheumatologist to help with the diagnosis, she added.
“This condition is more serious, and can result in irreversible joint damage,” Husni said.
A rarer form of psoriasis is guttate psoriasis, which can cause punctate-type lesions all over the arm or, in some cases the entire body resembling chickenpox, Husni said. It typically occurs after an infection, with strep infection being most common. There is also erythrodermic psoriasis, which presents with a fiery red, all-encompassing psoriasis, she added.
Another type is inverse psoriasis, which presents with flat lesions that usually occur underneath the breast or under the groin area.
“However, that type is tricky, because there are other conditions that can occur in those areas — such a yeast infection or a Candida infection — so you must be careful that you are diagnosing the correct type of psoriasis,” she said.
Working like a detective
According to Husni, patients with very mild cases, with symptoms found only in their ear and other hidden places, will take some true detective work to find. The best way to accomplish this is to start by simply asking the patient about their symptoms, she said.
“The first thing I will do is ask the patient if they have noticed any spots or rashes that are irritating them, because the patient knows their body best,” Husni said. “Any rashes or irritations that are new that they want me to know about, and then I go from there and see if they are similar to psoriasis. After that, performing an exam with their clothes off is important, so you can see their back and other areas that the patient may not be able to see themselves.”
According to Fernandez, the key for both rheumatologists and dermatologists is to never simply assume that what they see on the skin is limited only to the skin. Physicians should recognize that when people experience rashes in certain locations, they should inquire about any systemic symptoms to help distinguish between a specific dermatologic condition that may mimic a systemic disease, and an actual systemic disease.
“The key for dermatologists and rheumatologists is to be on the lookout for these mimic diseases,” Fernandez said. “For example, with systemic lupus and the malar rash, the biggest thing we will see is a patient with rosacea, which can sometimes lead to a difficulty in distinguishing the two among rheumatologists. However, on the flip side, a dermatologist could inquire about other conditions and symptoms to distinguish the two.”
There can also be difficulties in distinguishing the difference between the dermatologic symptoms of psoriasis and eczema. According to Fernandez, a rheumatologist may assume that patients with eczema have psoriasis because of certain joint symptoms.
“We as dermatologists sometimes struggle in making this distinction as well,” he said. “Occasionally, even a biopsy of a skin lesion isn’t enough to distinguish between the two.”
Dermatomyositis can be another troublesome condition to diagnose for rheumatologists, according to Fernandez. In such cases, they may sometimes associate a heliotrope rash on the face with edema.
“Even patients who present with allergic contact dermatitis can present with a similar picture, and we have certainly seen patients that have been misdiagnosed in either direction,” he said. “I have referred patients from rheumatologists who were diagnosed with allergic contact dermatitis who, in fact, had rather serious dermatomyositis.”
The importance of working together
Due to the difficulties involved in examining and diagnosing patients with dermatologic symptoms on one’s own, both Fernandez and Husni stressed the importance of collaboration to greatly improve patient outcomes. According to Fernandez, patients with systemic diseases can only benefit from collaborations between physicians within different specialties, who can combine their knowledge to develop an overarching treatment plan.
“[Husni] and I do that certainly on psoriasis patients, but also other patients as well,” Fernandez said. “Just utilizing the particular knowledge each specialist has can help make sure that we’re addressing every organ system that is involved with the best overall treatment plan.”
According to Husni, working together with a dermatologist could help rheumatologists devise better treatment plans, particularly when it comes to topical creams. She added that physicians should avoid exposing patients to systemic immunosuppressant medication when what they see on the skin may not be a true systematic disease.
“They may recommend certain types of topicals and introduce nuances into the treatment process,” Husni said. “I think the process is benefited when you go about it in a collaborative manner.”
Above all, Fernandez noted that rheumatologists should take special care to pay attention to even the smallest details, and to not jump to conclusions based on dermatologic symptoms alone.
“Be aware that just because a patient has cutaneous manifestations in anatomic locations that fit a particular rheumatologic disease, it doesn’t always mean that that is what the manifestation represents,” Fernandez said. “It’s important to not quickly jump to conclusions based on what you see on the skin, and it’s important to work with a dermatologist in these difficult cases, if only to ensure you get an appropriate diagnosis and to confirm you are giving the patient the best treatment plan.” – by Jason Laday
For more information
Anthony P. Fernandez, MD, PhD, can be reached at 9500 Euclid Avenue, Cleveland, Ohio 44195; email: fernana6@ccf.org.
M. Elaine Husni, MD, MPH, can be reached at 9500 Euclid Avenue, Cleveland, Ohio 44195; email: husnie@ccf.org.
Disclosure: Fernandez reports professional relationships with Celgene, AbbVie, Pfizer, Roche and Mallinckrodt. Husni reports no relevant financial disclosures.