Good response of a combined treatment of acitretin and antibiotics in blastomycosis-like pyoderma

ARTICLE

Auteur(s) : Xue-lian Lu¹, Wen Zhao², Yu-kun Xia², Jing Chen², Ling Wang², Xiao-wei Zhou², Wei-da Liu¹

¹Department of Mycology, Institute of Dermatology, Chinese Academy of Medical Sciences& Peking Union Medical College, Road Jiangwangmiao No.12, 210042 Nanjing, China
²Dalian Hospital of Skin Diseases, China

Here we report a patient with localized blastomycosis-like pyoderma who showed a poor response to conventional antibiotic treatment and cryotherapy, but a dramatic response to a combined treatment of low-dose acitretin and sensitive antibiotics.

A 23-year-old man presented with a proliferative plaque and recurrent pyorrhea on the right toes for two years. He suffered a painless soybean-sized nodule on his toe, initially from abrasion by slippers. The nodule spontaneously ruptured with pyorrhea and gradually enlarged. The first diagnosis was a wart. Following cryotherapy the lesion disappeared temporarily, yet one month later, miliary papules and pustules with pyorrhea recurred and gradually formed a coin-sized, dark-red, infiltrative plaque with desquamation and significant hyperplasia. Cryotherapy was administered again, resulting only in a more severe lesion with a central swelling and pyorrhea. The patient experienced intermittent local pain and physical activity limitation, and then received oral amoxicillin for one month and oral clarithromycin for approximately six months, with no significant effect. The lesion was re-diagnosed as subcutaneous mycosis and the patient was administered ketoconazole orally, 200 mg/d for three months, resulting in a slight improvement in the first month but worsening over the next two months. There was no history of sunburn, alcohol abuse or halogen intake.

Cutaneous examination revealed a round, dark-red verrucous hyperplasia plaque (4 cm × 4 cm) with a clear boundary at the roots of the right toes, accompanied by punctiform blood crust formation. Fresh ulceration with pus and blood secretion was observed under the crust. The margin was red and elevated, surrounded by satellite lesions with miliary papules and pustules (figure 1A). Routine laboratory examinations including complete blood count, liver function, and serum lipid and protein levels were normal. Treponema pallidum hemagglutination assay and human immunodeficiency virus antibody tests were also negative. The analysis of T-cell subsets in peripheral blood revealed a decreased population of CD4⁺ T cells (23.2%, normal 25.8-41.6%), and a decreased CD4⁺/CD8⁺ ratio (0.77%, normal 0.98-1.98%). Tissue biopsy specimens and under-crust secretion samples were collected for direct microscopic examination, and then cultured three times, which showed growth of only Staphylococcus epidermidis, without fungal or mycobacterial growth. Histopathology revealed pseudoepitheliomatous hyperplasia and a dermal inflammatory infiltrate consisting of neutrophils, lymphocytes, and plasmocytes, and no multinucleated giant cells were observed (figures 1C, D). Ziehl-Neelsen, periodic acid-Schiff, and silver stain were both negative. Based on the presentation of large verrucous plaques with elevated borders and pustules, pseudoepitheliomatous hyperplasia, with a dermal inflammatory infiltrate histologically, positive bacterial cultures and negative cultures for fungi and mycobacteria, the diagnosis was strongly suggested to be blastomycosis-like pyoderma, though our patient did not meet all criteria for diagnosis as the halogen level could not be ascertained [1]. After the final diagnosis, the patient was administered an oral dose of 20 mg acitretin daily, combined with 250 mg cefuroxime three times and 400 mg rifampin daily, which were selected according to antibiotic sensitivity test results. After four months of therapy, the lesion resolved with only an atrophic scar remaining (figure 1B). The duration of combined treatment was five months, and no recurrence was observed during the three month follow-up after discontinuing the drug treatment.

Blastomycosis-like pyoderma responds poorly to regular treatment methods [2]. This case failed to respond to conventional antibiotic treatment and cryotherapy, but a special combined treatment of low-dose acitretin and sensitive antibiotics showed a dramatic therapeutic benefit. Though a similar therapy has been reported by Nguyen et al. [3], more comparative studies should be undertaken to confirm the effectiveness of this therapy.

Acknowledgements

References

2 Stone OJ. Hyperinflammatory proliferative (blastomycosis-like) pyodermas: review, mechanisms, and therapy. J Dermatol Surg Oncol 1986; 12: 271-3.

3 Nguyen RT, Beardmore GL. Blastomycosis-like pyoderma: Successful treatment with low-dose acitretin. Australas J Dermatol 2005; 46: 97-100.