Immune checkpoint inhibitors have proven to be efficacious for a broad spectrum of solid organ malignancies. These monoclonal antibodies lead to cytotoxic T-cell activation and subsequent elimination of cancer cells. However, they can also lead to immune intolerance and immune-related adverse event (irAEs) that are new and specific to these therapies. Cutaneous irAEs are the most common, arising in up to 34% of patients on PD-1 inhibitors and 43% to 45% on CTLA-4 inhibitors. The most common skin manifestations include maculopapular eruption, pruritus, and vitiligo-like lesions. A grading system has been proposed, which guides management of cutaneous manifestations based on the percent body surface area (BSA) involved. Cutaneous irAEs may prompt clinicians to reduce drug doses, add systemic steroids to the regiment, and/or discontinue lifesaving immunotherapy. Thus, the goal is for early identification and concurrent management to minimize treatment interruptions. We emphasize here that the severity of the reaction should not be graded based on BSA involvement alone, but rather on the nature of the primary cutaneous pathology. For instance, maculopapular eruptions rarely affect <30% BSA and can often be managed conservatively with skin-directed therapies, while Stevens-Johnson syndrome (SJS) affecting even 5% BSA should be managed aggressively and the immunotherapy should be discontinued at once. There is limited literature available on the management of the cutaneous irAEs and most studies present anecdotal evidence. We review the management strategies and provide recommendations for psoriatic, immunobullous, maculopapular, lichenoid, acantholytic eruptions, vitiligo, alopecias, vasculitides, SJS/toxic epidermal necrolysis, and other related skin toxicities.

Type 2 immunity, illustrated by T helper 2 lymphocytes (Th2) and downstream cytokines (IL-4, IL-13, IL-31) as well as group 2 innate lymphoid cells (ILC2), is important in host defense and wound healing. ¹ The hallmark of type 2 inflammation is eosinophilia and/or high IgE counts and is best recognized in atopic diathesis. Persistent eosinophilia, such as seen in hypereosinophilic syndromes, leads to fibrosis and hence therapeutic Type 2 inhibition in fibrotic diseases is of high interest. Furthermore, as demonstrated in cutaneous T cell lymphoma, advanced disease is characterized by Th1 to Th2 switch allowing cancer progression and immunosuppression. Development of targeted monoclonal antibodies against IL-4Rα (eg, dupilumab) led to a paradigm shift for the treatment of atopic dermatitis (AD) and stimulated research to better understand the role of Type 2 inflammation in other skin conditions. In this review, we summarize up to date knowledge on the role of Type 2 inflammation in skin diseases other than AD and highlight whether the use of Type 2 targeted therapies has been documented or is being investigated in clinical trials. This manuscript reviews the role of Type 2 inflammation in dermatitis, neurodermatitis, IgE-mediated dermatoses (eg, bullous pemphigoid, chronic spontaneous urticaria), sclerodermoid conditions and skin neoplasms.

Dupilumab, a monoclonal antibody against the common receptor of interleukin (IL)-4 and IL-13, was the first biologic therapy approved in Canada for treatment of moderate-to-severe atopic dermatitis (AD). While it is considered safe and effective, dupilumab is not universally effective and 8%-38% of patients develop conjunctivitis, while some patients develop head and neck dermatitis. Thus, new therapeutic options are warranted. While both IL-4 and IL-13 play important roles in the pathogenesis of AD, it has been recently demonstrated that IL-13 is the primary upregulated cytokine in AD skin biopsy samples. A placebo-controlled phase 2b clinical trial evaluating the efficacy and safety of lebrikizumab, an IL-13 inhibitor, in AD demonstrated that, at 16 weeks, Eczema Area and Severity Index (EASI) 75 and Investigator’s Global Assessment (IGA) 0/1 were achieved by 60.6% and 44.6% of patients taking lebrikizumab at its highest dose (vs 24.3% and 15.3% of patients taking placebo, respectively). Moreover, treatment with lebrikizumab was associated with rapid improvement of pruritus and low rates of conjunctivitis (1.4%-3.8%). Another IL-13 monoclonal antibody, tralokinumab, was evaluated for safety and efficacy in moderate-to-severe AD. By week 12, among adults receiving 300 mg tralokinumab, 42.5% achieved EASI-75 and 26.7% achieved IGA 0/1 score (vs 15.5% and 11.8% in the placebo group, respectively). Both lebrikizumab and tralokinumab demonstrated acceptable safety profiles in AD (and non-AD) trials with adverse events often being comparable between treatment and control groups. Thus, IL-13 inhibitors may provide a safe and effective treatment alternative for patients with moderate-to-severe AD.

Systemic sclerosis (SSc) is a severe, chronic, and incurable autoimmune fibrotic skin disease with significant extracutaneous involvement. Low concordance rate in twin studies and unequal geographic distribution of SSc argues for importance of environment in disease initiation and progression. In this manuscript we provide a summary of all investigated potential external risk factors for SSc. A literature search in PubMed and EMBASE database was performed for studies published until January 1, 2020 by 2 reviewers (EN and LO) independently. Occupational and/or environmental exposures to silica and organic solvents are associated with increased incidence and severity of SSc. Exposure to epoxy resins, asbestos, and particulate air pollution favors increased risk of SSc, but data are based on limited number of observational studies. There is insufficient evidence to conclude an association between SSc development and other occupational (eg, welding fumes) or personal exposures (eg, smoking, vitamin D deficiency). Association of SSc with silicone breast implants has been disproven. Infectious pathogens (eg, Helicobacter pylori and angiotropic viruses) and dysbiosis seem to play a role in SSc development and severity, but their role remains to be clarified. It may be prudent to counsel our patients with SSc (or those at risk of SSc) to avoid occupations with exposure to silica, organic solvents, asbestos and epoxy resins; restraint from smoking, using cocaine or drugs with pro-fibrotic potential. While the association between low vitamin D and SSc remains to be confirmed, we believe that SSc patients should be encouraged to maintain healthy vitamin D levels as benefits outweigh the risks.

Bullous pemphigoid (BP) is an autoimmune blistering skin disease. Current treatment strategies are limited by their efficacy and/or side effect profile and the need for safer and effective alternatives is undeniable. We aimed to conduct a systematic review focusing on the efficacy and safety of omalizumab in BP patients. Embase, PubMed, Cochrane, and clinicaltrials.gov were searched for English and French articles published from inception to July 1, 2021, using search terms “omalizumab” OR “Xolair” OR “IGE025” OR “olizumab” AND “bullous pemphigoid.” Screening and data extraction was performed by two raters independently. The primary outcome was complete response (CR), and secondary outcomes were partial response (PR), flare-ups, adverse events/vital status. In total, 22 articles were included, with a total of 56 patients. All patients had a refractory BP with mean disease duration of 13.5 ± 20.2 months (Standard Deviation (SD)) and failed 3.1 ± 1.6 therapies and many remained corticosteroids dependent. Overall, 87.5% of patients responded to treatment (55.4% CR and 32.1% PR), 7.1% discontinued the protocol and only 5.4% were non responders. A third of patients were able to discontinue all other therapies and most others were able to discontinue or taper systemic corticosteroids to <10 mg daily. Flare-ups occurred in 57.7% of patients upon discontinuation of omalizumab and/or steroid tapering, most patients recaptured response thereafter. Omalizumab was well tolerated by most patients. Omalizumab appears to be a promising treatment for BP with a good response rate and safety profile. However, several limitations were identified in current literature, and highlight the need for randomized controlled trials of omalizumab in BP.