Current and emerging tests for diagnosis of cutaneous blastomycosis William B. Adams, MD, University of Louisville, Department of Dermatology, Louisville, KY, United States; Andrew H. Kalajian, MD, University of Louisville, Department of Dermatology, Louisville, KY, United States; Jeffrey P. Callen, MD, University of Louisville, Department of Dermatology, Louisville, KY, United States
Potassium hydroxide examination in superficial fungal infection of the skin: The experience-based procedure Sumanas Bunyaratavej, MD, Department of Dermatology, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand
Background: Blastomyces dermatitidis is a dimorphic fungus classically located in the southeastern United States. A unique feature of this pathogen is its ability to cause significant disease in immunocompetent patients. Cutaneous blastomycosis most commonly arises via hematogenous spread following primary pulmonary infection although direct cutaneous inoculation does rarely occur. Diagnosis can be very difficult given the variety of presentations and difficulty in isolation of the organism. Herein we describe a case of cutaneous blastomycosis and discuss current and future diagnostic tests that may aide in the identification of this pathogen. Observation: A 41-year-old African American woman presented with a firm violaceous to erythematous verrucous plaque with pustules on the upper cutaneous lip. Upon further questioning, she related a 3-month history of fever, chest congestion, arthralgias, and myalgias that preceded her first cutaneous lesion. Shortly thereafter, she developed pustular plaques on the dorsal surface of her left hand and left shoulder, followed by the development of a similar lesion in her left conchal bowl, which was excised. Histologic examination showed pseudoepitheliomatous hyperplasia overlying suppurative granulomas, but no organisms were found with special stains or cultures. Tissue culture from the upper lip plaque revealed no growth at 6 weeks. A chest CT showed a left-sided lobar consolidation, and bronchoscopy with tissue sampling was performed. Subsequently, histologic evaluation of a newly developed nodular plaque on her chest revealed broad based budding yeast on Grocott methenamine silver stain consistent with B dermatitidis. All cultures from pulmonary and cutaneous sources remained negative. The patient was started on fluconazole 200mg twice daily for 1 month and was then switched to itraconazole 400mg daily, resulting in dramatic resolution of all cutaneous lesions over the following 3 months. Comment: The isolation of B dermatitidis can be extremely difficult. Differential diagnosis includes sarcoidosis, pyoderma gangrenosum, squamous cell carcinoma, halogenodermas, or other cutaneous infections. Given the prevalence of this fungus and its ability to cause marked morbidity in immunocompetent people, significant search has been undertaken for nonculture diagnostic modalities. Some of the newer ideas to arise are a polymerase chain reaction (PCR) for the DNA of B dermatitidis and measurement of a urinary antigen.
Background: Potassium hydroxide (KOH) examination is commonly used in dermatologic practice. The experience in specimen collection, preparation, and interpretation is very important, despite its simplicity, rapidity, and minimal invasiveness. This study determined the ability in interpretation of KOH preparation of six technicians with different levels of experience within the department of dermatology ranging from the least to the most. Methods: Six volunteer technicians who know basic KOH examination have had different levels of practical experience defined as specimens per week (SPW), ranging from\0.05 to 250 SPW. Each technician examined the 10 unknown slides of skin scraping in the first session, 10minutes/slide. Next, all six technicians were paired in three groups (2 per each). Each of them was asked to exchange the set of 10 slides to the other member for slide interpretation in the second session, 3 to 5minutes per slide. Results of this examination, based on fungal culture and clinical features, were classified as correct, false negative, false positive, and misinterpretation. Results: This study shows that experienced technicians can interpret more correct answers than the fairly experienced group in both sessions, especially in the second session which had more limited time for specimen interpretation. Noticeably, there was positive correlation (r ¼ 1.0, Spearman rank; P ¼ .01) between SPW and the correct answers. Furthermore, there was negative correlation (r ¼ -1.0, Spearman rank; P \ .01) between SPW and misinterpretation, exclusively in the second session. Conclusion: Experience of slide examination per week and time exposure were significant factors for accurate interpretation of KOH examination. Positive correlation between experience and the correct answers and also negative correlation between experience and misinterpretation were identified particularly in limited examination time. Commercial support: None identified.
Commercial support: None identified.
P2405 Severe nail candidiasis in a diabetic patient Ana Moreira, MD, CHVNGaia/Espinho, Vila Nova de Gaia, Portugal; Armando Baptista, MD, CHVNGaia/Espinho, Vila Nova de Gaia, Portugal; Ineˆs Leite, MD, CHVNGaia/Espinho, Vila Nova de Gaia, Portugal; Virgı´nia Lopes, MD, Centro Hospitalar do Porto, Porto, Vila Nova de Gaia, Portugal We report the case of a 79-year-old woman who consulted our department with a severe deformation of the distal phalange of the third finger of the left hand, with a yellowish, opaque, rough, exuberant hyperkeratosis that destructed the entire nail plate. She had diabetes, peripheral arterial disease with amputation of the right leg, cardiac stroke, and left foot ulceration history. A nail surgical avulsion was performed. Biopsy of the nail bed showed an acute inflammatory process with epidermal and dermal involvement and numerous spores were detected by PAS staining. There was no sign of malignancy. KOH-prepared direct microscopy revealed the presence of numerous spores and pseudohyphae. Candida albicans was isolated and identified by cultivation. Routine serum analyses were normal except for elevated fasting glucose levels and hemoglobin A1c. The Rx of the left hand revealed clinodactyly of the fingers and severe osteopenia. The distal phalange of the third left finger did not reveal osteolytic or sclerotic changes. Imidazoles (fluconazole, itraconazole) were administered and after 4 years of intermittent treatment her clinical findings had substantially improved. C albicans and C parapsilosis are the species identified more frequently from nails, particularly from fingernails. Because they could be resident flora of the skin, cultures should be interpreted according to clinical data, direct microscopic observation of clinical samples, and quantification of colonies. Onychomycosis has the potential to cause severe complications in diabetics and should be treated promptly. The existence of comorbid conditions and potential for drug interactions complicates the selection of an appropriate treatment regimen. The role of Candida in onychomycosis may be of increased significance in the diabetic population due to an underlying vulnerability to this organism. The exuberance of the cutaneous lesion and the slow answer to the administered treatment make, in our opinion, a particularly interest example of the impact of diabetes on C albicans infection of the nails. Commercial support: None identified.
P2407 Naftifine: A topical antifungal agent reevaluated Lawrence Charles Parish, MD, Jefferson Medical College, Philadelphia, PA, United States; Hirak B. Routh, MBBS, Paddington Testing Company, Philadelphia, PA, United States; Jennifer L. Parish, MD, Jefferson Medical College, Philadelphia, PA, United States Naftifine, the first of two available allylamine antifungal agents, was originally synthesized in 1974. Initial screens showed this agent to be fungicidal against dermatophytes and fungistatic against yeasts. It also was shown to have both antibacterial and antiinflammatory activity. Its mechanism of action against fungi involves the inhibition of squalene epoxidase and of ergosterol. The increased squalene formation and decreased ergosterol formation of the cell walls interfere with intake of nutrients by the fungi. Clinically, naftifine penetrates the skin transdermally, and in vivo, a 1% cream formulation maintained epidermal pentration for 5 to 10 days after application, providing concentrations up to five times higher than the miniumum inhibitory concentration (MIC) for pathogens such as Trichophyton mentagraphytes. This is the basis for the recommendation of a once-a-day regimen. A trial in the treatment of a 1% cream formulation showed superior clinical and mycological efficacy over a fungistatic azole, oxiconazole, at the end of 2 weeks. In a comparision with another azole, econzaole, naftifine had favorable results at 4 weeks in the treatment of tinea cruris and tinea corporis. The currently available gel and cream formulations have had minimal side effects, which have been limited to occasional minor irritation and one instance of contact dermatitis. Dermatophyte resistance to the allylamines has been extremely rare. Commercial support: 90% supported by MerzUSA.
J AM ACAD DERMATOL