Dermatomyositis

Question 1

What type of muscle weakness does dermatomyositis cause?

Answer 1

Symmetrical proximal muscle weakness.

Question 2

What makes dermatomyositis distinct from polymyositis?

Answer 2

Characteristic skin lesions are present.

Question 3

Is dermatomyositis idiopathic or associated with other diseases?

Answer 3

It may be idiopathic or associated with connective tissue disorders or underlying malignancy.

Question 4

Which cancers are commonly associated with dermatomyositis?

Answer 4

Ovarian, breast, and lung cancers.

Question 5

What percentage of dermatomyositis patients have an associated malignancy?

Answer 5

20–25% (higher in older adults).

Question 6

What major clinical step must be performed after diagnosing dermatomyositis?

Answer 6

Screening for underlying malignancy.

Question 7

What condition is considered a variant of dermatomyositis without skin features?

Answer 7

Polymyositis.

Question 8

What type of rash on the back and shoulders is characteristic of dermatomyositis?

Answer 8

Photosensitive macular rash.

Question 9

What is the classic periorbital rash seen in dermatomyositis?

Answer 9

Heliotrope rash.

Question 10

What are Gottron’s papules?

Answer 10

Roughened red papules over the extensor surfaces of the fingers.

Question 11

What are “mechanic’s hands” in dermatomyositis?

Answer 11

Extremely dry, scaly hands with linear cracks on the palmar and lateral aspects of the fingers.

Question 12

What nail sign is associated with dermatomyositis?

Answer 12

Nail fold capillary dilatation.

Question 13

What systemic symptom involving circulation may occur in dermatomyositis?

Answer 13

Raynaud’s phenomenon.

Question 14

What respiratory complication can dermatomyositis cause?

Answer 14

Respiratory muscle weakness.

Question 15

Which interstitial lung diseases may occur in dermatomyositis?

Answer 15

Fibrosing alveolitis or organising pneumonia.

Question 16

What oesophageal and laryngeal symptoms can occur in dermatomyositis?

Answer 16

Dysphagia and dysphonia.

Question 17

Are ANA antibodies common in dermatomyositis?

Answer 17

Yes — around 80% are ANA positive.

Question 18

What proportion of dermatomyositis patients have anti-synthetase antibodies?

Answer 18

Around 30%.

Question 19

Which anti-synthetase antibody targets histidine-tRNA ligase?

Answer 19

Anti-Jo-1.

Question 20

Which autoantibody targets the signal recognition particle (SRP)?

Answer 20

Anti-SRP antibody.

Question 21

Which antibody is classically associated with dermatomyositis and good response to therapy?

Answer 21

Anti-Mi-2 antibody.