Case discussion
The 28-yr-old female had a 15-day history of gradual onset of erythematous petechial rashes, predominantly in lower limb and abdomen. History revealed that the rashes appeared in crops and faded in 3-4 days, however some were ulcerative and non-itchy. Clinical investigation revealed that the patient was positive for ANA, ANCA positive and anti-PR3. The lesions were raised, petechial, purpuric and ecchymosis. The complement levels were normal. CRP and ESR were elevated.
The prominent clinical presentation in the present case was purpura. The purpuric lesions should be differentiated from thrombocytopenic/non-thrombocytopenic lesions. The probability of thrombocytopenic causes could be excluded, since the platelet counts were normal and no associated features of bleeding were reported. Non-blanching of the lesion, while pressing, indicated that it wnnjmas extravascular. Purpura may be classified as: palpable and non-palpable. Non-palpable purpura is caused by blood leaking from a normal blood vessel due to trauma or a hematologic problem like thrombocytopenia, coagulation defects or capillary fragility. While palpable purpura causes are inflammation around the blood vessels. The differential diagnoses are vasculitis and an inflammation due to infection around the blood vessels. Henoch-Schönlein purpura (HSP)is common in children, while vasculitis is common in adults (rarely allergic-leukocytoclastic vasculitis). These lesions represent small vessel vasculitis of various causes. Rarely, the vasculitis may not be palpable in the early stages, and may show blanching (Riordan, 1996). Petechial lesions restricted to the area above the clavicles signify a benign cause, generally accompanied by coughing or vomiting. Various causes of purpura are listed in table 1.
Table 1: Categorization of various causes of purpura
The palpable and non-blanching rashes noted in the current case suggest the possibility of vasculitis or allergic rashes. The presence of arthralgia and a few ulcerating rashes indicated the possibility of vasculitis. The non-ulcerative palpable lesions are small vessel vasculitis, while ulcerating lesions are medium to small vessels. Clinical clues, which may help in categorizing the size of the vessels involved, are given in below table 2.
Clinical features |
Most likely affected vessels |
Most commonly associated systemic vasculitis |
Cutaneous |
Palpable purpura |
Post-capillary venules |
Any type of vasculitis except giant cell arteritis and Takayasu's arteritis |
Skin ulcers |
Arterioles to small arteries |
Polyarteritis, Churg-Strauss vasculitis, Wegener's granulomatosis, hypersensitivity vasculitis |
Gangrene in an extremity |
Small to medium-sized arteries |
Polyarteritis, Churg-Strauss vasculitis, Wegener's granulomatosis |
Gastrointestinal tract |
Abdominal pain or mesenteric ischemia |
Small to medium-sized arteries |
Henoch-Schönlein purpura, polyarteritis, Churg-Strauss vasculitis |
Gastrointestinal bleeding |
Capillaries to medium-sized arteries |
Henoch-Schönlein purpura, polyarteritis, Churg-Strauss vasculitis |
Renal |
Glomerulonephritis |
Capillaries |
Microscopic polyangiitis, Wegener's granulomatosis, cryoglobulinemia, Churg-Strauss vasculitis, Henoch-Schönlein purpura |
Ischemic renal failure |
Small to medium-sized arteries |
Polyarteritis, Takayasu's arteritis; less commonly, Churg-Strauss vasculitis and Wegener's granulomatosis |
Pulmonary |
Pulmonary hemorrhage |
Capillaries; less commonly small to medium-sized arteries |
Microscopic polyangiitis, Wegener's granulomatosis |
Pulmonary infiltrates or cavities |
Small to medium-sized arteries |
Churg-Strauss vasculitis, microscopic polyangiitis |
Neurologic |
Peripheral neuropathy |
Small arteries |
Polyarteritis, Churg-Strauss vasculitis, Wegener's granulomatosis, cryoglobulinemia |
Stroke |
Small, medium-sized or large arteries |
Giant cell arteritis, SLE-associated vasculitis |
The probable diagnoses are: HSPor hypersensitivity vasculitis (HSV), drug-induced vasculitis, and other primary vasculitis including microscopic polyangiitis; among infections rickettsial infections, viral infections and streptococcal infections; secondary causes of vasculitis including lupus. The presence of ulcerating lesions is not commonly seen in HSP and HSV. ACR classification criteria for HSP are given in table 3.
Table 3: ACR classification criteria for HSP
Criterion |
Definition |
Palpable purpura |
slightly elevated purpuric rash over one or more areas of the skin not related to thrombocytopenia |
|
|
Age at onset |
< 20 years Development of first symptoms at age 20 years or less |
|
|
Bowel angina |
Diffuse abdominal pain worse after meals, or bowel ischemia, usually bloody diarrhea |
|
|
Wall granulocytes on biopsy |
Histological changes showing granulocytes in the walls of arteries or venules |
Note: For the purpose of classification, a patient shall be said to have HSP if at least 2 of these 4 criteria are present. The presence of any 2 or more criteria yields a sensitivity of 87.1% and specificity of 87.7%
It is important to consider the possibility of other vasculitis and other similar rashes. Clinical characteristics to be considered for differentiating different types of C- ANCA-positive vasculitis are listed in table 4.
Table 4: Clinical characteristics differentiating different types of C- ANCA-positive vasculitis
Conditions |
Wegener's Granulomatosis |
Microscopic Polyangitis |
Polyarteritis
Nodosa |
Chrug Strauss Syndrome |
Comments |
Pulmonary infiltrates or nodules |
+++ |
++ |
- |
+++ |
Asthama and eosinophilia CSS |
Alveolar hemorrhage |
++ |
++ |
- |
+ |
|
Glomerulonephritis |
+++ |
+++ |
- |
++ |
Progressive renal failure uncommon in CSS |
Upper airway disease |
+++ |
+ |
+ |
++ |
ENT disease usually favours WG |
Skin / purpura |
+ |
+++ |
- |
++ |
|
Peripheral nervous system |
++ |
+ |
++ |
+++ |
Often a prominent feature of CSS |
Central nervous system |
+ |
+ |
+ |
++ |
|
The patient did not fulfil the complete criteria for the diagnosis of Wegener's or any of the vasculitis. In addition, no systemic clinical features of definable syndrome of ANCA-associated vasculitis were reported. In order to confirm the diagnosis of ANCA-positive cutaneous vasculitis, skin biopsy of an active lesion, ENT evaluation for asymptomatic involvement, and chest and PNS X-rays to exclude the possible involvement of these organs were conducted.
Final diagnosis
ANCA-associated cutaneous vasculitis
Course of treatment
She was managed on small doses of steroids and azathioprine. The rashes reduced and symptomatically improved. The patient is on regular follow-up and there is no further organ involvement.