Actinic keratoses (AKs) are atypical, precancerous proliferations of keratinocytes that develop because of chronic exposure to ultraviolet (UV) radiation. Treatment of AK can be lesion-directed or field-directed. Field cancerization theory postulates that the skin surrounding AK is also at increased risk for possible malignant transformation since it has been exposed to the same chronic UV light. Field-directed therapies thus have the potential to address subclinical damage, reduce AK recurrence rates, and potentially reduce the risk of squamous cell carcinoma (SCC) development. Published clinical studies have found lesion clearance rates ranging from 81 to 91% for photodynamic therapy (PDT) with either aminolevulinic acid (ALA) or methylaminolevulinate (MAL). Clinical studies have also been published on various topical treatments. Complete clinical clearance (CCC) was significantly higher in patients treated with a combination of 5-fluorouracil and salicylic acid (5-FU-SA) than in the vehicle group across multiple studies, and CCC ranged between 46 and 48% following treatment with imiquimod. Additionally, treatment with diclofenac sodium (DFS) found reduction in lesion sizes to range from 67 to 75%. Reported results have been similar for another non-steroidal anti-inflammatory drug (NSAID), piroxicam, which has more cyclooxygenase (COX)-1 activity than DFS. Active treatments with ingenol mebutate were also significantly more effective than vehicle at clearing AK lesions. All treatments resulted in mild, localized skin reactions. PDT using conventional light sources was associated with increased severity of pain and/or discomfort, while PDT using daylight as the light source was associated with less pain and occasionally no pain at all. Though no widely accepted algorithm for the treatment of AKs exists, field-directed therapy can be particularly useful for treating photo-exposed areas containing multiple AKs. Additional research with more direct comparisons between these field-directed therapies will help clinicians determine the best therapeutic approach. Here, we provide a balanced and comprehensive narrative review of the literature, considering both light-based and topical therapies with a focus on their field-therapy aspects, and propose a therapeutic algorithm for selecting an appropriate treatment in the clinical setting.

While many studies have examined the barrier effects of large rivers on animal dispersal and gene flow, few studies have considered the barrier effects of small streams. We used displacement experiments and analyses of genetic population structure to examine the effects of first-order and second-order streams on the dispersal of terrestrial red-backed salamanders, Plethodon cinereus (Green, 1818). We marked red-backed salamanders from near the edges of one first-order stream and one second-order stream, and experimentally displaced them either across the stream or an equal distance farther into the forest. A comparison of return rates indicated that both streams were partial barriers to salamander movement, reducing return rates by approximately 50%. Analysis of six microsatellite loci from paired plots on the same side and on opposite sides of the second-order stream suggested that the stream did contribute to genetic differentiation of salamander populations. Collectively, our results imply that low-order streams do influence patterns of movement and gene flow in red-backed salamanders. We suggest that given the high density of first-order and second-order streams in most landscapes, these features may have important effects on species that, like red-backed salamanders, have limited dispersal and large geographic ranges.

Atopic dermatitis (AD) is a chronic inflammatory skin disease, with a remitting relapsing course. The central diagnostic features of AD include pruritus, xerosis, eczematous lesions with a characteristic morphology and distribution, and a personal or family history of atopic disease. Several clinical studies have emphasized the link between AD and other atopic disorders including asthma, allergic rhinitis, and food allergies. More recent studies indicate possible links between AD and other nonatopic disorders, including ADHD, sleep disturbance, and mental health disorders, suggesting an even more profound impact of this disease. Furthermore, the social, emotional, and personal impact of AD for patients and their caregivers is substantial. Understanding both the clinical characteristics and implications of AD is critical to lessening the psychosocial, clinical, and economic burden of this disease.

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Blastomycosis-like pyoderma (BLP) is a rare, exaggerated, vegetative tissue reaction that occurs in patients with local or systemic immune dysregulation. Reported causes of immune compromise include human immunodeficiency virus, malnutrition, alcoholism, leukemia, immunosuppressant use, radiation therapy, and others. Nearly all cases involve an underlying, prolonged pyogenic bacterial infection. Historically monotherapy with systemic antibiotics requires long-term treatment and often fails. We describe a case of a male patient with BLP of the face and scalp, which cultured positive for methicillin-resistant Staphylococcus aureus (MRSA). Subsequent evaluation uncovered a concurrent Treponema pallidum and HIV infections. Treatment of the MRSA with a short course of doxycycline and the syphilis with penicillin, resulted in complete resolution of the skin lesions. Highly Active Anti-Retroviral Therapy for HIV was initiated after the skin lesions had cleared. Resolution of BLP by antibiotic therapy alone in the context of untreated HIV leads the authors to postulate that syphilis may have been the relevant factor contributing to his immune dysregulation.