Methotrexate has been used for over half a century to treat a wide spectrum of skin conditions. It is a valuable steroid sparing agent, preventing protracted steroid courses and their undesirable side effects. While many alternative therapies exist and continue to emerge to treat these dermatologic conditions, the long history, affordability, and relative safety associated with methotrexate ensure its enduring utility. Further, ongoing research focusing on the pharmacogenetic properties of the drug may allow for more effective and targeted therapeutic strategies.

Dermatitis herpetiformis (DH) is an autoimmune, pleiomorphic, papulovesicular disorder associated with celiac disease and gluten sensitivity. DH is characterized by subepidermal bullae on hematoxylin and eosin staining and granular immunoglobulin A deposits in the dermal papillae using the direct immunofluorescence method. Antibodies to tissue transglutaminase and epidermal transgulatminase can be measured serologically, although biopsy is still required for definitive diagnosis of DH. Gluten free diet (GFD) is the first-line therapeutic approach that can alleviate both cutaneous and intestinal manifestations of this condition, while dapsone and sulfones target the skin eruption only. Combined therapy with GFD and dapsone is an initial treatment of choice to control the cutaneous manifestations of DH. This article will provide a comprehensive review of DH, including its epidemiology, clinical and pathological findings, diagnostic evaluation, and management.

Parabens are preservatives used in a variety of personal care, cosmetic, pharmaceutical and food products. Studies have confirmed the ubiquitous presence of parabens, with levels detected in wastewater, rivers, soil and house dust. Parabens have also been detected in human tissues and bodily fluids, but it is the discovery of these chemical compounds in the breast tissue of patients with breast cancer that has raised public concern over their use. It is hypothesized that the estrogenic properties of parabens may play a role in breast cancer development. However, studies investigating the health effects of parabens are conflicting. At this point, there is an insufficient amount of data suggesting serious consequences from paraben use and exposure to warrant drastic avoidance measures or government regulations.

The exact role of biologics in the treatment of pediatric psoriasis remains undefined but is evolving. Biologics are an attractive option for use in children in part because they offer more convenient dosing regimens and less frequent laboratory monitoring than traditional systemic agents. Further, because their action is targeted, they theoretically lack many of the potential end-organ toxicities of traditional agents. However, compared to adult psoriasis populations, there is a relative lack of long-term safety data specific to the pediatric psoriasis population. Thus, the clear advantages of using biologic agents must be balanced with a measure of caution. This article will provide a summary of the cumulative pediatric safety and efficacy data for the anti-tumor necrosis factor-alpha (TNF-α) agents and interleukin (IL)-12 and IL-23 (IL12/23) pathway inhibitor and suggestions for a rational clinical approach to their use in children with psoriasis.

Urticaria and angioedema are common allergic manifestations and some forms of this disorder may be increasing in both prevalence and severity due to changes in medications, environment and other unknown factors. This review focuses on a rational approach to differential diagnosis and therapy of the most common forms of urticaria and angioedema.

Skin cancer in organ transplant recipients is a serious problem that manifests as increased squamous cell carcinoma in longterm patients. In these patients, a combination of cumulative sun exposure as well as the immunosuppressive effects of transplant medications can cause cutaneous malignancy. Skin cancer can affect transplant patients in multiple ways. It can decrease quality of life by causing various separate skin cancers that require frequent and sometimes painful treatment, as well as possibly result in disfigurement. The more aggressive tumors pose a risk of metastasis and death. Clinical efforts aimed at reduction in skin cancers in this high-risk population include increased education and surveillance, aggressive treatment of skin cancers and pre-cancers, changes to immunosuppressive regimens, and retinoid chemoprevention.

Cutaneous T-cell lymphomas are rare, distinct forms of non-Hodgkin's lymphomas. Of which, mycosis fungoides (MF) and Sézary syndrome (SS) are two of the most common forms. Careful, clear classification and staging of these lymphomas allow dermatologists to commence appropriate therapy and allow correct prognostic stratification for those patients affected. Of note, patients with more advanced disease will require multi-disciplinary input in determining specialist therapy. Literature has been summarized into an outline for classification/staging of MF and SS with the aim to provide clinical dermatologists with a concise review.

Rosacea is a common chronic skin disorder that has significant impact on the self-esteem and quality of life of affected individuals. Currently understood as an inflammatory condition that occurs in the context of an altered innate immune response, the available topical and systemic therapies function as immunomodulators to restore cutaneous homeostasis. The goals of therapy include reduction of papules, pustules, erythema and physical discomfort with improvement in quality of life. Standard topical treatments include metronidazole and azelaic acid, although many other agents and regimens have been presented. Subantimicrobial/antiinflammatory dose oral doxycycline was US FDA approved in 2006 for the management of rosacea, but Health Canada clearance was only recently granted for this indication. Furthermore, renewed research interest has led to the development of other emerging therapies including topical ivermectin, brimonidine and oxymetazoline that hold promise for patients suffering from this condition.

Device-based therapies are promising alternatives for the treatment of onychomycosis because they can mitigate some of the negative factors associated with treatment failure. There are four categories of device-based treatments: laser devices, photodynamic therapy, iontophoresis, and ultrasound. These therapeutic modalities are noninvasive procedures that are carried out by medical professionals, reduce the need for long-term patient adherence, and avoid adverse reactions associated with conventional systemic antifungal therapies.

Propionibacterium acnes (P. acnes) is an anaerobic bacteria implicated in the pathogenesis of acne. The last 30 years have witnessed an alarming increase in resistance to antibiotics commonly employed to treat acne. Antibiotic resistance in acne represents a significant international public health concern because resistance can occur in more pathogenic bacteria than P. acnes, and an increase in pathogenic P. acnes has been reported. Current treatment guidelines offer strategies to limit the potential for resistance while achieving optimal outcome in the management of inflammatory and non-inflammatory acne.