The Dermatomyositis Skin Severity Index (DSSI) is based on the PASI (Psoriasis Activity and Severity Index) scoring system for psoriasis. The DSSI can be used over time and to monitor the patient's response to therapy. The authors are from Wake Forest University in Winston-Salem, North Carolina.
Patient selection: dermatomyositis
Parameters:
(1) body regions as percent of body surface area
(2) extent of body region affected
(3) extent of psoriatic changes (severity)
Body Region
Code
Percent Body Surface Area
head
H
10%
trunk
T
20%
upper extremities
U
30%
lower extremities
L
40%
Portion of Body Region Affected
Points for Anatomical Extent
0 (none)
0
< 10%
1
10 to 30%
2
31 to 50%
3
51 to 70%
4
71 to 90%
5
> 90%
6
Changes in DM
Code
erythema (redness)
R
induration
I
scaliness
S
Severity for Each Change
Points for Extent
none
0
mild
1
moderate
2
moderate to severe
3
severe
4
DSSI =
= SUM ((percent BSA in body region) * ((extent erythema in region) + (extent infiltration in region) + (extent desquamation in region)) * (extent of body region affected)) =