Dermatomyositis
Examination
“Examine this patient’s skin/face/hands”
“Look and proceed”
“This patient has dysphagia, please examine her”
(Similar to sun-exposed rash)
 Face
 Helitrope rash
 Neck and shoulder – shawl sign
 Weakness of neck flexion
 Conjunctival pallor (associated with myeloproliferative or GI malignancies)
 SLE or SScl for overlap syndrome
 Hands
 Grottron’s sign
 Vasculitis, capillary loops at the base of fingernails
 Raynaud’s phenomenon
 Calcinosis (usually in children)
 SLE or SScl or RA for overlap syndrome
 Upper limbs
 Elbows for rashes
 Tenderness of muscles
 Test power, demonstrating proximal weakness
 Loss of reflexes
 Show no loss of sensory
 Knees for rash
 Request to screen for underlying mitotic lesions such as breast, respiratory and
abdominal examination and screen for interstitial fibrosis.
Presentation
Sir, this patient has got dermatomyositis.
There is the presence of heliotrope rash, which is a purplish-blue rash, around
the eyelids and periorbital area and on the dorsum of the hands. This erythematous
rash is also present on the neck and the shoulders, ie in a “shawl” distribution as well
as on the sun-exposed areas. There is also involvement of the extensor surfaces of the
elbow and knees. There is also periorbital edema.
Examination of the hands reveals also presence of Grottron’s papules, which
are flat-topped, violaceous papules over the dorsum of the knuckles and
interphalangeal joints. The erythematous rash spares the phalanges. There is presence
of nailfold vasculitis and telengiectasias. The cuticles are irregular, thickened and
distorted. There is hyperkeratosis of the palms which resembles a mechanic’s hands. I
did not notice any Raynaud’s phenemenon. There is also no calcinosis.
There is tenderness of the muscles with proximal weakness. There is no
sensory loss. There is also weakness of neck flexion.
I did not detect any clinical features of Systemic sclerosis or systemic lupus
erytthromatosis or rheumatoid arthritis to suggest an overlap syndrome. I would like
to complete the examination by screening for any associated underlying mitotic
lesion.
There are also no features of chronic steroid use.
Questions
What is dermatomyositis?
It is an idiopathic inflammatory myopathy with characteristic cutaneous
findings.
How do you diagnose DM/PM?
4 out of 5 criteria:
 Progressive, proximal, symmetrical muscle weakness
 Raised CK
 Cs EMG findings
 Cs findings on muscle Bx
 Compatible dermatological findings
What are the types of dermatomyositis?
 Dermatomyositis
 Polymyositis
 Amyopathic dermatomyositis (no muscle involvement, just skin features)
How do you classify?
5 Groups, Group 1 to 5 respectively
 Idiopathic polymyositis
 Idiopathic dermatomyositis
 A/w neoplasia
 Childhood a/w vasculitis
 A/w collagen vascular disease
How would you investigate this patient?
 Creatinine kinase levels – raised and reflects disease activity
 ANA levels, anti-Mi-2, anti-Jo1
 EMG – myopathic changes which are spontaneous fibrillations, salvos of
repetitive potentials and short duration of polyphasic potentials of low amplitudes
 Muscle biopsy – necrosis and phagocytosis of muscle fibres, with interstitial and
perivascular infiltration of inflammatory cells.
 Ba swallow – for atonic dilated esophagus (if stem statement states patient has
dysphagia)
 Other Ix to rule out malignancy (breast, lungs and GIT, ovaries) and mixed CT
disease
What is your differential diagnosis for myositis with raised CK levels?
 Statin, chloroquine and colchicine
What are some disorders associated with myositis?
 Drugs
 Infectious – Lyme’s disease, CMV
 Eosinophilic myositis
Outline your management.
 Educate and counselling
 Treat underlying malignancy


General meausures
 Skin – sun avoidance and sunscreens
 Muscle – bedrest, PT and OT, ST and bed elevation if dysphagia
Medical treatment
 Steroid treatment (prednisolone 1mg/kg/day)
 IVIG, methotrexate or azathioprine
 Calcium channel blockers eg diltiazem for calcinosis
What is the prognosis?
Depends on
 Presence of underlying malignancy
 Severity of myopathy
 Presence of cardiopulmonary involvement