What is the initial treatment approach for a patient with cutaneous polyarteritis nodosa (CPAN)?

Treatment of Cutaneous Polyarteritis Nodosa

For patients with cutaneous polyarteritis nodosa (CPAN), initiate treatment with moderate-dose oral glucocorticoids (prednisone 0.25-0.5 mg/kg/day, typically 10-40 mg/day) combined with azathioprine as the preferred initial regimen. 1

Initial Treatment Approach

The treatment strategy for CPAN differs fundamentally from systemic PAN and should be approached as a distinct entity:

First-Line Therapy

• Start prednisone at moderate doses (0.25-0.5 mg/kg/day, typically 10-40 mg/day in adults) combined with azathioprine for initial disease control 1
• The American College of Rheumatology explicitly states their systemic PAN recommendations do not apply to isolated cutaneous disease, and azathioprine-based regimens are superior for cutaneous manifestations 1
• This moderate-dose approach contrasts with severe systemic PAN, which requires high-dose glucocorticoids (1 mg/kg/day) 2

Alternative Agents for Mild Disease

For patients without ulcerations or severe manifestations, consider less aggressive options:

• Antiplatelet agents alone achieved remission in a substantial proportion of patients (64% received antiplatelet therapy in one cohort) 3
• Vasodilators can be combined with antiplatelet agents (39% of patients) 3
• Dapsone may be used in combination regimens 4
• Some patients with very mild disease achieved remission with compression therapy alone or observation 3

Duration of Immunosuppressive Therapy

• Continue azathioprine at full therapeutic doses for at least 18 months after achieving sustained remission 1
• This recommendation is based on the monophasic nature of disease in many patients, though relapses do occur 2
• Sustained remission is defined as complete absence of clinical signs or symptoms attributed to PAN, whether on or off therapy 2, 5

Glucocorticoid Tapering Strategy

• The glucocorticoid taper should be slower rather than faster, particularly in patients with ulcer history 1
• The American College of Rheumatology acknowledges the optimal duration is not well established, but faster tapers in other vasculitides led to more flares 2
• Duration should extend beyond 6 months in most cases, guided by clinical response 2

Predictors of Need for Systemic Corticosteroids

Certain clinical and laboratory features identify patients who will require glucocorticoid therapy:

• Presence of skin ulcers strongly predicts need for systemic corticosteroids 3
• Elevated peripheral white blood cell count before treatment 3
• Elevated erythrocyte sedimentation rate (ESR) before treatment 3
• Markedly elevated ESR (>50 mm/h) predicts treatment resistance and potential need for limb amputation 3

Treatment Escalation for Refractory Disease

If initial therapy fails:

• Add additional immunosuppressive agents including methotrexate, mycophenolate, or cyclophosphamide 4
• Other reported agents include hydroxychloroquine, sulfasalazine, sulphapyridine, tacrolimus, and thalidomide 4
• Biologic therapy with rituximab has been reported in isolated cases 6
• For patients with multiple drug failures and markedly elevated ESR, be prepared for potential limb amputation 3

Monitoring Strategy

• Serial clinical examinations focusing on new skin lesions, ulcers, or nodules are essential for monitoring disease activity 1
• Avoid routine repeated invasive testing in stable patients 2
• Monitor for infection risk given immunosuppression, particularly with azathioprine 5

Common Pitfalls to Avoid

• Do not treat CPAN with the aggressive regimens used for severe systemic PAN (cyclophosphamide plus high-dose glucocorticoids) unless there is evidence of systemic involvement 1
• Do not obtain superficial skin punch biopsies for diagnosis—deep-skin biopsies reaching medium-sized vessels of the dermis are required 2, 7
• Do not underestimate the significance of ulcerations and elevated ESR as these predict more aggressive disease requiring systemic therapy 3
• More than half of CPAN patients can achieve remission without corticosteroids, so avoid overtreatment in mild cases 3