Asymptomatic Cutaneous Polyarteritis Nodosa: Treatment Options and Therapeutic Guidelines

First-line treatment of CPAN includes nonsteroidal anti-inflammatory drugs (NSAIDS) and colchicine.⁷ Nonsteroidal anti-inflammatory drugs are preferred; however, they also have been associated with gastrointestinal tract upset and increased risk for peptic ulcer disease with long-term use. Although colchicine often is used in conjunction with NSAIDS⁸ for its anti-inflammatory activity, no studies have been performed on this drug as monotherapy, and the side effect of diarrhea often limits its use.

Other therapies include dapsone, which should be monitored carefully due to the risk for dapsone hypersensitivity syndrome.^8,9 Topical corticosteroids have been proven effective for mild cases of confluent erythema with remission occurring as early as 4 weeks.⁴ Some reports emphasize the role of streptococcal infections in CPAN, especially in children.^8,10-12 Consequently it is recommended that anti–streptolysin O titers should be included in the workup for CPAN. Long-term penicillin prophylaxis and tonsillectomy have been used to prevent disease flares with limited success.^8,10-12

For more severe disease, especially with neuromuscular involvement, oral methylprednisolone up to 1 mg/kg daily has been used and has proven effective in the control of acute exacerbations.^7,13 However, the many adverse effects of systemic steroids limit their use long-term, and taper will often result in flare of disease.^4,7 Medications used in conjunction with steroids include hydroxychloroquine, dapsone, azathioprine, cyclophosphamide, methotrexate, sulfapyridine, pentoxifylline, infliximab, etanercept, and intravenous immunoglobulin.^4,9,12-17

Low-dose methotrexate has shown some improvement in skin disease with CPAN, but other case reports suggest that complete remission is not achieved with this drug.^15,18 More studies are needed to assess the use of methotrexate for CPAN.

Immunomodulators have been used in multiple case reports with varying levels of success. Rogalski and Sticherling⁴ reported 3 cases that cleared with methylprednisolone plus azathioprine ranging from 4 weeks to 6 months; nausea limited tolerance of azathioprine in 1 case. Mycophenolate mofetil also was successfully used in 2 cases with clearance at 17 weeks and 6 months. In this series of cases, cyclosporine was ineffective for CPAN.⁴ Two case reports documented cutaneous clearance with cyclophosphamide in conjunction with prednisolone.^9,10 No prospective trials have been performed on these medications, and immunosuppressants should only be considered in steroid-resistant cases.

The use of intravenous immunoglobulin has been reported effective in prior cases that showed resistance to more conventional trials of steroids, azathioprine, and/or cyclophosphamide.^12,14 Intravenous immunoglobulin may be regarded as a treatment option for severe resistant disease. Several case reports also have documented success using tumor necrosis factor α blockers, particularly infliximab, as an adjunct to steroids and etanercept as both a steroid adjunct and monotherapy.^16,17,19 More studies are necessary to evaluate these treatments.

Additionally, single case reports have outlined the use of other therapeutic agents, including tamoxifen (10 mg twice daily increased to 20 mg twice daily during episodes of breakthrough lesions),²⁰ hyperbaric oxygen therapy (100% oxygen for 90 minutes 5 times weekly at 1.5 atm absolute followed by 2 weeks of 2 atm absolute),²¹ and granulocyte-macrophage colony-stimulating factor (300 µg injection in small portion to ulcer edges twice monthly for 2 months).²² All of these treatments show promise, but data are limited.

Because thrombosis is postulated to be a potential mechanism leading to CPAN, agents such as pentoxifylline, clopidogrel, and warfarin have been examined as treatment options. Pentoxifylline in combination with mycophenolate mofetil has been successful in treating a case that was resistant to other immunosuppressants.²³ Clopidogrel blocks the adenosine diphosphate pathway and impairs clot retraction. Clopidogrel was reported effective in an acute flare of CPAN for clearance of skin lesions and normalization of lupus anticoagulant.²⁴ It also was used successfully in recurrent CPAN after steroid treatments in a patient with neuromuscular symptoms. There was no recurrence in either of the patients in this case report series. Warfarin therapy at an international normalized ratio of 3.0 also has demonstrated success in halting disease progression and in facilitating the resolution of skin changes and normalization of anti–phosphatidylserine-prothrombin complex antibodies.²⁴ Our review of the literature did not reveal evidence of a standardized length of treatment following symptom resolution or if treatment is indicated in asymptomatic disease, or as in our case, with only mild elevations of antiphospholipid antibodies.

Conclusion

Multiple treatment options exist for CPAN, but the data on their efficacies is limited and based only on anecdotal evidence, not prospective analysis. We believe that it seems reasonable to initiate treatment only for symptomatic disease or cases in which the antibody titers suggest that the patient may be at high risk for thrombosis. Mild symptoms and mild cutaneous changes would suggest the likely choice of NSAIDs, colchicine, or dapsone as treatment options versus no treatment. In patients with antibody titers, pentoxifylline, clopidogrel, or warfarin may be considered first-line therapies. With severe ulcerative lesions and neuromuscular involvement, steroids, immunosuppressants, and other investigative agents should be contemplated. In our patient, the laboratory studies were repeated and normalized on complete resolution of her livedo eruption. She remained asymptomatic and clear for 8 months without any treatment. The incidence of this presentation of CPAN is unknown and is likely underreported, as we would not expect most patients to present to their physicians for the evaluation of otherwise asymptomatic livedo reticularis. In essence, our case report suggests that it may be prudent to simply monitor patients with asymptomatic CPAN.