Henoch-Schonlein Purpura can be diagnosed by using a classification tree approach.
top level |
second level |
third level |
fourth level |
diagnosis |
palpable purpura present |
age at onset <= 20 |
|
|
HSP |
|
age > 20 |
extra or perivascular granulocytes on biopsy |
|
HSP |
|
|
no granulocytes on biopsy |
|
non-HSP |
palpable purpura absent |
age <= 20 |
extra or perivascular granulocytes |
|
HSP |
|
|
no granulocytes on biopsy |
GI bleeding |
HSP |
|
|
|
no GI bleeding |
non-HSP |
|
age > 20 |
|
|
non-HSP |
Surrogate criteria:
• if biopsy data not available with palpable purpura and age > 20 years, then GI bleeding may be used
Criteria |
Comment |
palpable purpura |
slightly raised "palpable" hemorrhagic skin lesions, not related to thrombocytopenia |
age <= 20 years at onset of first symptom |
|
gastrointestinal bleeding |
passage of melena, grossly bloody stool, or a positive result for occult blood in stool (usually by the guiac method) |
extravascular or perivascular granulocytes on biopsy |
granulocytes in a perivascular cuff around arterioles or venules, or in an extravascular location |
Patient Subsets |
Findings |
HSP patients |
palpable purpura present; age <= 20 |
|
palpable purpura present; age > 20; extravascular or perivascular granulocytes on biopsy |
|
palpable purpura absent; age <= 20; extravascular or perivascular granulocytes on biopsy |
|
palpable purpura absent; age <= 20; no extravascular or perivascular granulocytes on biopsy; GI bleeding present |
non-HSP patients |
palpable purpura present; age > 20; no extravascular or perivascular granulocytes on biopsy |
|
palpable purpura absent; age <= 20; no extravascular or perivascular granulocytes on biopsy; GI bleeding absent |
|
palpable purpura absent; age > 20 |
Specialty: Immunology/Rheumatology