DESTIN, FLA. – Dermatomyositis doesn’t always present with the violaceous upper eyelid erythema and associated edema seen in textbook cases.
Rather, it often presents without muscle disease and with pink eyelid erythema, mid-facial erythema that hugs the nasolabial folds and extends onto the forehead, and subtle scaly pink plaques on the knuckles, Dr. Ruth Ann Vleugels said at the annual Congress of Clinical Rheumatology.
Dr. Vleugels described an unfortunate case involving a patient with this type of amyopathic presentation who presented to the emergency department with shortness of breath and what was thought to be a pulmonary infection. The patient was admitted to the intensive care unit, and dermatology was not consulted until the third day.
Unfortunately, the patient died in the ICU, said Dr. Vleugels of the department of dermatology at Harvard Medical School and director of the Autoimmune Skin Diseases Program at Brigham & Women’s Hospital, Boston.
The patient had skin-limited dermatomyositis; his family reported that his rash had been present for more than a year, she said.
Even Gottron’s papules, which are pathognomonic for dermatomyositis, don’t always present as pink to violaceous papules on the knuckles as expected. In some cases they can be very subtle – especially in darker skin types – and sometimes there is involvement between the knuckles as well, Dr. Vleugels said.
She described another patient who had been misdiagnosed with flat warts on the back of her hands before being diagnosed with dermatomyositis. In some cases, the papules are very scaly and can be mistaken for psoriasis, she noted.
"We have to recognize these clinical features," she said.
One helpful tip: Examine the nail folds. Nearly all dermatomyositis patients with active disease "have nice-looking nail folds," explained Dr. Vleugels.
"So the feature we will be looking for is cuticular hypertrophy," she said, noting that women tend to be acutely aware of this symptom and may want to push their cuticles back.
Dilated capillary loops, dropout capillaries, and hemosiderin deposition of the nail fold are also common.
"Really look at those nail folds. Lupus patients do not have nail folds like this," Dr. Vleugels emphasized.
Another clue to diagnosing dermatomyositis is poikiloderma in sun-exposed areas, characterized by redness, dispigmentation, and atrophy or thinning of the skin.
Poikiloderma becomes permanent, which is one reason why photoprotection is critical in these patients, said Dr. Vleugels. It can also involve the scalp (sometimes in addition to scaling), and in fact is "probably an underrecognized feature in our dermatomyositis patients," she said.
The condition is very pruritic and detrimental to quality of life, and hair loss can occur in association with the disease activity on the scalp.
"We treat this as a component of the rash, so if we don’t get their scalp better we increase or change their immunosuppressive therapy," Dr. Vleugels noted.
Keep in mind that poikiloderma can also occur on the lateral thighs (the "holster sign"), even though this is not typically a sun-exposed area, she added.
A recent study found that the MDA5 autoantibody, in particular, is associated with certain cutaneous findings in dermatomyositis. The most common was ulcerations in Gottron’s papules, and this is representative of vasculopathy (J. Am. Acad. Dermatol. 2011; 25-34).
Such ulcerations are not a sign of infection, but a sign that the disease is active and required more aggressive treatment.
Calcinosis is another concern, and occurs more often in children than adults.
However, "good data from the pediatric literature say if we treat these patients early and aggressively, they get less calcinosis," Dr. Vleugels said.
In an adult who is developing calcinosis, consider changing their overall treatment regimen, as this is a sign of active disease, she added.
"Mechanic’s hands" can be another sign of dermatomyositis, particularly if there is scaling and fissures on the lateral and palmar aspects of the fingers (as opposed to scaly Gottron’s papules elsewhere on the hands); this cutaneous phenotype is associated with high risk of antisynthetase syndrome or lung involvement, she said.
Recognizing these signs and symptoms of dermatomyositis can help prevent outcomes such as the death of the patient in the ICU after presenting with unrecognized fulminant lung disease associated with dermatomyositis, Dr. Vleugels emphasized.
"Our skin-limited patients are the ones who are often missed, and these are the ones who have approximately equal risk of lung disease and malignancy," she said.
Data suggest these conditions occur in about 25% of patients with skin-limited dermatomyositis
"So even the patients with amyopathic disease need to have regular screening with pulmonary function tests with diffusion capacity," she said.