Dermamyositis

Question 1

What is dermatomyositis (DM)?

Answer 1

A systemic autoimmune disease characterized by chronic inflammation of the skin and muscles, often associated with other systemic features.

Question 2

What is the hallmark feature of dermatomyositis?

Answer 2

A combination of proximal muscle weakness and distinctive cutaneous findings.

Question 3

What is the typical age of onset for dermatomyositis?

Answer 3

Bimodal distribution: in children (juvenile DM) and adults aged 40–60 years

Question 4

What is the underlying cause of dermatomyositis?

Answer 4

Unknown, but it involves immune-mediated damage to muscle and skin, possibly triggered by environmental factors in genetically predisposed individuals

Question 5

What is the primary immunopathologic mechanism in dermatomyositis?

Answer 5

Complement-mediated microangiopathy causing damage to capillaries in the skin and muscle.

Question 6

Which autoantibodies are commonly associated with dermatomyositis?

Answer 6

Anti-Mi-2: Associated with classic DM and good prognosis.

Anti-Jo-1: Associated with interstitial lung disease (ILD) and mechanic’s hands.

Anti-TIF1γ and anti-NXP2: Associated with malignancy in adult DM.

Question 7

What type of muscle weakness is seen in dermatomyositis?

Answer 7

Symmetrical proximal muscle weakness (e.g., difficulty climbing stairs, rising from a chair).

Question 8

Are distal muscles typically involved in dermatomyositis?

Answer 8

Rarely, and usually only in severe cases.

Question 9

Is muscle pain a common feature of dermatomyositis?

Answer 9

Muscle pain or tenderness occurs in some cases but is not a prominent feature.

Question 10

What is the most specific skin finding in dermatomyositis?

Answer 10

Gottron’s papules: Violaceous, scaly papules over bony prominences like the knuckles, elbows, and knees.

Question 11

What is the characteristic rash seen on the face in dermatomyositis?

Answer 11

Heliotrope rash: A violaceous discoloration around the eyelids, often with periorbital edema.

Question 12

What is the “shawl sign” in dermatomyositis?

Answer 12

A photodistributed erythematous rash over the shoulders, upper chest, and back.

Question 13

What is the “V sign”?

Answer 13

A photodistributed rash over the anterior chest in the shape of a “V”.

Question 14

What are “mechanic’s hands”?

Answer 14

Hyperkeratosis, cracking, and fissuring of the skin on the fingers, often associated with anti-synthetase syndrome.

Question 15

What systemic features are commonly associated with dermatomyositis?

Answer 15

Fatigue, weight loss, fever, Raynaud’s phenomenon, and interstitial lung disease (ILD).

Question 16

What gastrointestinal complication is seen in juvenile dermatomyositis?

Answer 16

Calcinosis: Calcium deposits in the skin and soft tissues.

Question 17

What malignancies are associated with adult dermatomyositis?

Answer 17

Ovarian, breast, lung, gastric, pancreatic, and colorectal cancers.

Question 18

What are the diagnostic criteria for dermatomyositis?

Answer 18

Symmetrical proximal muscle weakness.

Elevated muscle enzymes (CK, LDH, aldolase, AST/ALT).

Myopathic changes on electromyography (EMG).

Characteristic skin findings.

Muscle biopsy showing perifascicular atrophy and inflammation.

Question 19

What imaging modality is useful in diagnosing muscle involvement in dermatomyositis?

Answer 19

MRI, which can detect muscle edema and inflammation.

Question 20

Which skin biopsy finding is characteristic of dermatomyositis?

Answer 20

Interface dermatitis with a lymphocytic infiltrate and basal layer vacuolization.

Question 21

What is the first-line treatment for dermatomyositis?

Answer 21

High-dose corticosteroids (e.g., prednisone) to suppress inflammation.

Question 22

What steroid-sparing agents are commonly used in dermatomyositis?

Answer 22

Methotrexate and azathioprine.

Question 23

Which medication is used in refractory cases of dermatomyositis?

Answer 23

Intravenous immunoglobulin (IVIG), rituximab, or mycophenolate mofetil.

Question 24

How is skin disease in dermatomyositis managed?

Answer 24

Sun protection and avoidance of UV exposure.

Topical corticosteroids or calcineurin inhibitors (e.g., tacrolimus).

Antimalarials (e.g., hydroxychloroquine) for resistant cutaneous disease.

Question 25

What is the most common pulmonary complication of dermatomyositis?

Answer 25

Interstitial lung disease (ILD), which can range from mild to severe fibrosis.

Question 26

What cardiac complications may occur in dermatomyositis?

Answer 26

Myocarditis, arrhythmias, and congestive heart failure.