Antibiotics have a significant role in dermatology, treating a wide range of diseases, including acne, rosacea, inflammatory skin conditions and skin structure infections, such as cellulitis, folliculitis, carbuncles, and furuncles. Because of their consistent use, utility, and availability, antibiotics are susceptible to overuse within the medical practice, and, specific to this discussion, in the dermatologic setting. The issue of continuously increasing risk of antibiotic resistance remains an important concern to the dermatologist. The scope of this review will be to provide an overview of the common antibiotics used in the dermatologic setting with an emphasis on identifying areas of overuse, reported bacterial resistance, and discussion of clinical management aimed at decreasing antibiotic resistance.

h Paraconiothyrium cyclothyrioides is a recently described coelomycetous fungal species. We present a case in a renal transplant patient with chronic skin lesions of the lower extremities caused by P. cyclothyrioides. Treatment with posaconazole led to complete resolution of the lesions. P. cyclothyrioides should be considered an opportunistic human pathogen in immunocompromised patients. CASE REPORTA 49-year-old Latin American man with end-stage renal disease and a cadaveric renal transplant (2 years prior to the current admission) was hospitalized with cutaneous lesions in his lower extremities. The patient had history of type II diabetes, hypertension, and atrial fibrillation. One and half years previous to admission, the patient received thymoglobulin for acute T-cell rejection, with improvement of the episode. Approximately 6 months before the current admission, the patient first noticed a painless, nonpruritic, mildly tender scaly papule on the left tibia just inferior to the knee joint and applied a local adhesive band to prevent friction injury. Over the next few months, other lesions appeared on both tibial surfaces which then began to coalesce into violaceous, necrotic, plaque-like lesions with some areas of ulceration and crusting and mild self-limiting sanguineous discharge without accompanying fevers. The patient lives in Brownsville, TX, works in an office as a manager, and denied any travel outside Texas, trauma, or animal or insect bites. The patient's hobbies include performing mechanical work on car engines. Medications included leflunomide, prednisone, tacrolimus, doxazosin, clonidine, carvedilol, minoxidil, amlodipine, trimethoprim-sulfamethoxazole, insulin, famotidine, gemfibrozil, and pravastatin. His complete blood count was notable for a platelet count of 73 and creatinine of 2.4 mg/dl. On physical examination, he was afebrile and vital signs were stable. A cardiac examination evidenced an irregular rate and a II/VI murmur loudest in the apex. The lungs were clear, and the rest of the examination was unremarkable except for the lower extremities. He had a crusted, ulcerated plaque on the anteromedial aspect of the left knee (measuring 6 by 3 cm) and several similar-appearing lesions of smaller size on the same area (Fig. 1A). The patient was started on vancomycin (1.25 g every 24 h); radiographs of the knee did not reveal any bone abnormality. A skin biopsy specimen yielded a presumptive diagnosis of pyoderma gangrenosum, antibiotics were stopped, and the patient was discharged with wound care instructions and silver sulfadiazine.Two months prior to the current admission, a fungal culture from the skin tissue was positive for a single mold which grew on Sabouraud dextrose (Sab Dex) agar but was not identified at the time. Oral voriconazole (200 mg orally every 12 h) administration was initiated. A month after his discharge, he presented to the dermatology clinic with evidence of progression of his skin lesions and was again admitted to the hospital. He denied new recent trauma or travel h...

Acne and rosacea compromise a substantial portion of the dermatology clinical practice. Over the past century, many treatment modalities have been introduced with antibiotics playing a major role. Today, both oral and topical antibiotics are used in the management of acne and rosacea, with several novel formulations and/or combination regimens recently introduced. The latest studies suggest anti-inflammatory actions to be the most likely mechanism of antibiotics in acne and rosacea, shifting the focus to subantimicrobial-dose oral antibiotics and/or topical antibiotic regimens as the preferred first-line agents. Here we will discuss the most recent oral and topical antibiotic therapies available for treatment of acne and rosacea, with special focus on efficacy data, indication, dosing, and mechanism of action.

The majority of nonbacterial dermatological conditions treated with antibiotics benefit from the anti-inflammatory properties of these medications, usually dapsone or tetracycline. Many other antimicrobials are used to treat noninfectious conditions. The following chapter is an overview of select noninfectious dermatological conditions for which antibiotics are used, with a focus on the most common antibiotics used for their nonantimicrobial properties.

Herpes zoster, also known as shingles, occurs upon reactivation of a primary infection with varicella zoster virus (VZV). Risk factors for reactivation include stress, older age, and immunosuppression, all of which are associated with a decrease in host immunity. Common complications of herpes zoster include scarring and post-herpetic neuralgia (PHN). Cutaneous lesions such as granuloma annulare, lymphomas, and sarcoid granulomas have also been reported to potentially arise at the site of herpes zoster. Here, we report a case that to our knowledge is the first presentation of diffuse large B-cell lymphoma with its only cutaneous manifestation arising in a herpes zoster scar. Punch biopsy was performed on a nodule appearing in a dermatomal distribution within the herpes zoster scar. Histopathology revealed an atypical lymphoid infiltrate in the dermis that was determined to be CD20 positive B-cells. Immunostains for CD20, CD79a, and PAX-5 showed strong positive staining of the atypical cells, confirming B-cell origin and resulting in the diagnosis of lymphoma, large B-cell type. This case highlights the importance of raising clinical suspicion for a malignant process in patients who present with a changing or unresolving skin manifestation after infection with varicella zoster virus.