History
Persons with dermatomyositis often present with skin disease as one of the initial manifestations. In perhaps as many as 40% of individuals with dermatomyositis, the skin disease is the sole manifestation at onset. Muscle disease may occur concurrently, may precede the skin disease, or may follow the skin disease by weeks to years.
Muscle involvement manifests as proximal muscle weakness. Affected patients often begin to note muscle fatigue or weakness when climbing stairs, walking, rising from a sitting position, combing their hair, or reaching for items in cabinets that are above their shoulders. Muscle tenderness may occur but is not a regular feature of dermatomyositis.
Systemic manifestations may occur; therefore, the review of systems should assess for the presence of arthralgia, arthritis, dyspnea, dysphagia, arrhythmia, and dysphonia.
Malignancy is possible in any adult patient with dermatomyositis, but it is more common in adults older than 60 years. Only a handful of children with dermatomyositis and malignancy have been reported, and malignancy does not appear to be over-represented in the pediatric (ie, < 16 years) population.
A thorough history, review of systems, and assessment for previous malignancy should be performed in all patients with dermatomyositis to aid in evaluation for an associated malignancy. In the pediatric population, no further screening is recommended, whereas in the adult population, most experts support a thorough search for malignancy with age-related malignancy screening as well as blind imaging to rule out underlying malignancy.
Dermatomyositis in children is characterized by muscle weakness and resembles the adult form of the disease. Children commonly develop a tiptoe gait secondary to flexion contracture of the ankles in early childhood. Children tend to have extramuscular manifestations, especially gastrointestinal (GI) ulcers and infections, more frequently than adults. Extramuscular manifestations of the disease may include the following:
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General systemic disturbances, fever, arthralgia, malaise, weight loss, Raynaud phenomenon
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Dysphagia
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Gastroesophageal reflux
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Atrioventricular defects, tachyarrhythmias, dilated cardiomyopathies
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GI ulcers and infections
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Contracture of joints
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Pulmonary involvement due to weakness of thoracic muscles, interstitial lung disease
Na et al found the frequency of subcutaneous calcifications to be significantly higher in juvenile dermatomyositis than adult dermatomyositis. [4]
Several reports describe drug-induced dermatomyositis or existing dermatomyositis exacerbated by certain drugs, including statins and interferon therapy. Consequently, a medication history should be elicited in all patients. [47]
Physical Examination
Dermatomyositis is a disease that primarily affects the skin and the muscles, but may also affect other organ systems. The possibly pathognomonic cutaneous features of dermatomyositis are a heliotrope rash and Gottron papules.
The heliotrope rash consists of a violaceous to erythematous rash, with or without edema, in a symmetrical distribution involving the periorbital skin (see the image below). Sometimes this sign is subtle and may consist of only a mild discoloration along the eyelid margin. Similar to other areas, scale may be present on the eyelids. A heliotrope rash is rarely observed in other disorders; therefore, its presence is highly suggestive of dermatomyositis.
Gottron papules are flat-topped, erythematous to violaceous papules and plaques found over bony prominences, particularly the metacarpophalangeal joints, the proximal interphalangeal joints, and/or the distal interphalangeal joints. See the image below. They may also be found overlying the elbows, the knees, and/or the feet. A slight scale overlying the papules may be present, and, occasionally, a thick psoriasiform scale is observed. Gottron papules may clinically resemble lesions of lupus erythematosus; lichen planus; or, particularly in the event of psoriasiform scaling, psoriasis.
Gottron papules and nailfold telangiectasia are present in this patient with dermatomyositis.
Characteristic but not pathognomonic features include the following:
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Malar erythema
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Poikiloderma in a photosensitive distribution
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Violaceous erythema on the extensor surfaces
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Periungual and cuticular changes
Poikiloderma, which consists of erythema, hypopigmentation, hyperpigmentation, and telangiectasias, may occur on photoexposed skin, such as the extensor surfaces of the arm; the upper chest, in a "V-neck" configuration (see the image below); the upper back (shawl sign); or the lateral thighs (holster sign).
Patients often notice an eruption on photoexposed surfaces. The disease is often pruritic, and, sometimes, intense pruritus may disturb sleep patterns. Patients may also complain of a scaly scalp or diffuse hair loss (see the image below). [3]
Diffuse alopecia with scaly scalp dermatosis is common in patients with dermatomyositis.
Dilated capillary loops at the base of the fingernail are characteristic of dermatomyositis. Dropout of nailfold capillaries is also seen, along with cuticular hypertrophy and ragged cuticles. In patients with mechanic's hands, the palmar and lateral surfaces of the fingers may become rough and cracked. Mechanic's hands are linked to an increased risk of pulmonary disease as part of the anti-synthetase syndrome.
The above-mentioned pathognomonic and characteristic cutaneous lesions typically demonstrate interface dermatitis on histopathology. Other cutaneous lesions have been described in patients with dermatomyositis that do not reflect these interface changes. These include panniculitis (see the following image) and urticaria, as well as hyperkeratosis of the lateral palms and digits known as mechanic's hands, which has been associated with anti-synthetase antibodies. [48]
Other rare skin findings include the following:
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Cutaneous mucinosis
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Follicular hyperkeratosis
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Hyperpigmentation
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Ichthyosis
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White plaques on the buccal mucosa
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Cutaneous vasculitis
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Flagellate erythema
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Diffuse subcutaneous edema
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Vesiculobullous or erosive lesions
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Exfoliative erythroderma
Children with dermatomyositis may have an insidious onset that hides the true diagnosis until the dermatologic disease is clearly observed and diagnosed. Calcinosis is a complication of juvenile dermatomyositis (see the image below), but it is rarely observed at the onset of disease. The prognosis in children with dermatomyositis is worse in those in whom diagnosis is delayed.
Calcinosis caused by dermatomyositis in childhood can be observed in patient who had active dermatomyositis 15 years before time of this photograph.
Muscle disease commonly manifests as a proximal symmetrical muscle weakness. The degree of weakness may range from mild to moderate to severe; sometimes, quadriparesis is observed. Patients may have difficulty rising from a chair or squatting and then raising themselves from this position. Sometimes, in an effort to rise, patients use other muscles that are not as affected.
Testing of muscle strength is part of each patient assessment. Often, the extensor muscles of the arms are more affected than the flexor muscles. Distal strength is almost always maintained. Neck flexor weakness may also be seen.
Muscle pain and tenderness may be observed early in the course of the disease; muscle tenderness is a variable finding. Sensation is normal, and tendon reflexes are preserved unless the muscle is severely weak and atrophic.
Other systemic features include joint swelling, changes associated with Raynaud phenomenon, and abnormal findings on cardiopulmonary examination. When joint swelling occurs, the small joints of the hands are the most frequently involved. The arthritis associated with dermatomyositis is non-deforming. Patients with pulmonary disease may have abnormal breath sounds. Patients with an associated malignancy may have physical findings relevant to the affected organs.
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Heliotrope flower, for which characteristic manifestation of dermatomyositis is named.
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Heliotrope rash in a woman with dermatomyositis.
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Gottron papules and nailfold telangiectasia are present in this patient with dermatomyositis.
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These lesions on dorsal hands demonstrate photodistribution of dermatomyositis. Note sparing of interdigital web spaces.
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Diffuse alopecia with scaly scalp dermatosis is common in patients with dermatomyositis.
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Dermatomyositis is often associated with a poikiloderma in a photodistribution.
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Histopathology of dermatomyositis is interface dermatitis.
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Calcinosis caused by dermatomyositis in childhood can be observed in patient who had active dermatomyositis 15 years before time of this photograph.
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Histopathology of dermatomyositis showing inflammatory myopathic changes with a predominantly perivascular chronic inflammatory infiltrate.
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Calcifying panniculitis in patient with dermatomyositis.
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Ulceration over dorsal and lateral fingers in patient with dermatomyositis.
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Hematoxylin and eosin paraffin section shows polymyositis. Longitudinal section shows dense, chronic, endomysial inflammatory infiltrate. Image courtesy of Roberta J Seidman, MD.
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Hematoxylin and eosin frozen section shows polymyositis. Endomysial chronic inflammation is present among intact myofibers that are remarkable only for increased variability of fiber size. Image courtesy of Roberta J Seidman, MD.
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Hematoxylin and eosin paraffin section shows polymyositis. Patient had dense endomysial inflammation that contains abundance of plasma cells, which can be observed in patients with chronic polymyositis. Two necrotic myofibers, characterized by dense eosinophilic staining, are observed. Focal fatty infiltration of muscle is present in lower left quadrant of photomicrograph. Image courtesy of Roberta J Seidman, MD.
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Hematoxylin and eosin paraffin section shows polymyositis. Photomicrograph illustrates attack on nonnecrotic myofiber by autoaggressive T lymphocytes. On left, central myofiber is intact. On right, it is obliterated by segmental inflammatory attack. If immunohistochemistry were performed, expected findings would include admixture of CD8 T lymphocytes and macrophages in inflammatory process. Image courtesy of Roberta J Seidman, MD.
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Hematoxylin and eosin paraffin shows dermatomyositis. In dermatomyositis, inflammation is characteristically perivascular and perimysial. Vessel oriented approximately vertically in center has mild perivascular chronic inflammatory infiltrate. Endothelium is plump; wall is not necrotic. A few lymphocytes in wall of vessel are probably in transit from lumen to external aspect of vessel. Some observers may interpret this finding as vasculitis, but it is certainly neither necrotizing vasculitis nor arteritis. Image courtesy of Roberta J. Seidman, MD.
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Hematoxylin and eosin frozen section shows perifascicular atrophy in dermatomyositis. Fascicles in this sample show atrophy, predominantly at periphery, along connective-tissue border. Ischemia is considered to cause perifascicular atrophy. This finding is characteristic of dermatomyositis, mostly associated with juvenile form but also observed in adult form. Image courtesy of Roberta J Seidman, MD.
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Immunofluorescence for membrane attack complex of complement (MAC) in dermatomyositis. Bright ring of yellow-green fluorescence at center represents MAC in wall of microvessel. Finding was not present after treatment with steroids. Image courtesy of Roberta J Seidman, MD.
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A 47-year-old woman presented with a pruritic, diffuse rash across her upper hands and face that is worsened with sun exposure. ANA testing by outside providers was negative. Her rash was not responsive to topical steroids, and improved with oral prednisone but recurred with tapers beyond 15 mg daily. Diagnosis was dermatomyositis sine myositis. Image courtesy of Jason Kolfenbach, MD, and Kevin Deane, MD, Division of Rheumatology, University of Colorado Denver School of Medicine.
