Dactylitis

Question 1

What is the definition of dactylitis?

Answer 1

Inflammation of a digit (finger or toe).

Question 2

What group of conditions commonly causes dactylitis?

Answer 2

Spondyloarthritis (e.g. psoriatic arthritis and reactive arthritis).

Question 3

What haemoglobinopathy is a major cause of dactylitis?

Answer 3

Sickle-cell disease.

Question 4

What infectious and granulomatous conditions can rarely cause dactylitis?

Answer 4

Tuberculosis, sarcoidosis and syphilis.

Question 5

What is the significance of dactylitis in psoriatic arthritis?

Answer 5

Dactylitis is a hallmark feature and forms part of the CASPAR criteria for diagnosing psoriatic arthritis.

Question 6

Which age group most commonly develops dactylitis in sickle-cell disease?

Answer 6

Infants and young children aged 6 months to 4 years.

Question 7

What is the underlying mechanism of sickle-cell dactylitis?

Answer 7

Vaso-occlusive infarction of the small bones of the hands and feet.

Question 8

What structures become inflamed to produce the ‘sausage digit’ appearance in dactylitis?

Answer 8

A combination of synovitis, flexor tenosynovitis, and soft-tissue oedema.

Question 9

Which imaging modality best demonstrates tendon sheath inflammation in dactylitis?

Answer 9

Ultrasound.

Question 10

Which imaging finding on MRI supports dactylitis in spondyloarthritis?

Answer 10

Bone marrow oedema.

Question 11

In reactive arthritis, what does dactylitis commonly accompany?

Answer 11

Asymmetrical oligoarthritis, enthesitis, and preceding infection.

Question 12

What common condition must be differentiated from dactylitis when assessing a swollen digit?

Answer 12

Flexor tenosynovitis (Kanavel signs) or cellulitis.

Question 13

What pattern of joint involvement strongly suggests psoriatic arthritis when dactylitis is present?

Answer 13

Asymmetrical involvement with concurrent nail changes (e.g., nail pitting).

Question 14

What clinical pattern suggests sickle-cell dactylitis rather than rheumatological causes?

Answer 14

Painful swelling of hands and feet in a toddler with recurrent vaso-occlusive crises.