Discussion
Primary cutaneous actinomycosis is very rare, and risk factors include dental surgery, immunosuppression, maxillofacial trauma, local ischemia, and the presence of a foreign body.5 Actinomycosis occurs following damage to the skin or mucosa, leading to abscess formation with draining sinus tracts, fistulae, or mass lesions that are often misdiagnosed as cutaneous tumors.5-8 However, the patient’s prior facial surgery and her immunosuppression from chronic renal failure were the determining elements to suggest the actinomycosis diagnosis.4,9
Although actinomycosis is not actually an “opportunistic” disease, many reports3,10-12 of actinomycosis in immunosuppressed patients have been published recently. Actinomycosis without a history of surgery or trauma may indicate the need to evaluate an underlying immunological deficit. Early diagnosis remains important for extensive surgical treatment and decreased morbidity. If workups for tuberculosis and fungal infections are negative, a high degree of suspicion is needed to diagnose actinomycosis correctly.
Actinomycosis frequently imitates a neoplastic process when faced with an ill-defined and fixed mass. Facial forms are difficult to diagnose since the clinical presentation is often nonspecific and highly variable, but also because of a general lack of experience with the disease and the complicated microbiological identification.2 Although the definitive diagnosis of actinomycosis comes from positive cultures, a negative culture result does not exclude the diagnosis,13 as in this case where the culture result was negative. The diagnosis is most often made by the histological examination of tissue samples since the presence of characteristic clusters of organisms with sulfur granules is pathognomonic.14 Sulfur granules with Actinomyces colonies were shown in the histological examination in the case herein.
The treatment of a classical case of cutaneous actinomycosis includes high doses of intravenous antibiotics for 4–6 weeks followed by oral penicillin or amoxicillin for 6–12 months. In penicillin-resistant cases, the other alternatives are clindamycin, tetracycline, erythromycin, and chloramphenicol.15-17 The present patient received high doses of penicillin for 1 month and then clindamycin for 14 days. In the majority of the cases, surgical excision may ultimately be required for definitive diagnosis and treatment of actinomycosis. The prognosis depends on quick treatment. The infection is highly responsive to antibiotics, including penicillin and clindamycin, but prolonged treatment is needed in most cases. Surgical treatment is certainly necessary; however, cases complicated by fistula or abscess formation need to debulk necrotic and fibrotic tissues unresponsive to antibiotic treatment or to diagnose.2 Surgery alone is not curative.18 For this reason, there is a need for the combination of surgical intervention and antibiotics. With this dual treatment, better cosmetic results are obtained and the rate of recurrence is reduced.17,18