Helliwell et al developed a tool for evaluating dactylitis in a patient with psoriatic arthritis. This can be used to measure the initial involvement and to monitor the course of the disease with response to interventions. The authors are from the University of Leeds in England.
Dactylitis = diffuse swelling and inflammation of a digit (finger or toe)
Parameters:
(1) circumference of involved digit in mm
(2) reference circumference (below)
(3) tenderness score
The circumference of the digit is taken as close as possible to the web space, using a non-stretching measuring tape.
Reference circumference- one of the following:
(1) circumference of opposite digit, if unaffected/normal
(2) standard circumference from table below
|
Digit |
Male |
Female |
|
thumb |
70 mm |
58 mm |
|
index/second finger |
63 mm |
54 mm |
|
middle/third finger |
63 mm |
54 mm |
|
ring/fourth finger |
59 mm |
50 mm |
|
little/fifth finger |
52 mm |
44 mm |
|
great toe |
82 mm |
72 mm |
|
second toe |
52 mm |
46 mm |
|
middle/third toe |
50 mm |
44 mm |
|
fourth toe |
50 mm |
44 mm |
|
little toe |
52 mm |
45 mm |
|
Tenderness |
Points |
|
none |
0 |
|
mild |
1 |
|
wince |
2 |
|
withdraw |
3 |
score for digit =
= (((circumference of affected digit) - (reference circumference)) / (reference circumference)) * 100 * (points for tenderness)
total score for a visit =
= SUM(points for all 10 digits)
Interpretation:
• minimum score for a digit: 0
• maximum score for a digit: > 300
• minimum total score for a visit: 0
• maximum total score for a visit: > 3,000
Performance:
• The reference values would give lower values if the digit is smaller than normal, and higher values if the digit is larger than normal.
Specialty: Immunology/Rheumatology
