Psoriasis is a chronic T-cell–mediated inflammatory disease of the skin and joints. It has been suggested that patients with psoriasis are at an increased risk of cancer, and many cancer risk factors, including smoking and alcohol consumption, are associated with psoriasis.^1,2 Two large studies have found an increased risk of cancer overall, compared with either the general population or a reference population without psoriasis.^3,4 Lymphomas and keratinocyte cancer are more prevalent in patients with psoriasis than in control populations.^4-8 Approximately 1 in 4 patients with psoriasis develop psoriatic arthritis during their life course.⁹ Patients with psoriatic arthritis are considered to be more severely affected than those with psoriasis and often require systemic treatment. The risk of cancer in patients with psoriatic arthritis is also debated,¹⁰ but a collective assessment of the cancer risk in such patients is lacking.

Atopic dermatitis (AD) and food allergy (FA) share similar type 2 inflammation and commonly co‐occur, but the precise proportion of AD patients with FA and vice versa, as well as the effect of AD disease severity on the strength of this association remains uncertain. The aim of this comprehensive systematic review and meta‐analysis was to determine the prevalence and bidirectional associations of AD with food sensitivity (FS), FA and challenge‐proven food allergy (CPFA). We searched PubMed and EMBASE and three independent reviewers performed title/abstract and full‐text review and data extraction. Overall, 557 articles (n = 225,568 individuals with AD, n = 1,128,322 reference individuals; n = 1,357,793 individuals with FS, FA or CPFA, n = 1,244,596 reference individuals) were included in quantitative analyses. The overall pooled prevalence of FS, FA and CPFA in individuals with AD were 48.4% (95% confidence interval: 43.7–53.2), 32.7% (28.8–36.6) and 40.7% (34.1–47.5) respectively. AD prevalence among individuals with FS, FA and CPFA were 51.2% (46.3–56.2), 45.3% (41.4–49.3) and 54.9% (47.0–62.8) respectively. Children with AD had higher pooled FS (49.8% (44.4–55.1)) and FA (31.4% (26.9–36.1)) prevalences than adults with AD (28.6% (13.4–46.8) and 24.1% (12.1–38.7) respectively). Prevalences of FS and FA numerically increased with AD severity. FS, FA and CPFA are common comorbidities of AD and are closely related. Physicians should be attentive to this relationship to optimize management and treatment strategies in patients.

Biological agents including anti-tumor necrosis factor (anti-TNF; adalimumab, infliximab, etanercept) and anti-interleukin-12/13 (IL12/23; ustekinumab) are essential for treatment of patients with severe psoriasis. However, a significant proportion of the patients do not respond to a specific treatment. Pharmacogenetics might be a way to predict treatment response. Using a candidate gene approach, 62 mainly functional single-nucleotide polymorphisms (SNPs) in 44 different genes were evaluated in 478 Danish patients with psoriasis undergoing 376 series of anti-TNF treatment and 230 series of ustekinumab treatment. Associations between genetic variants and treatment outcomes (drug survival and Psoriasis Area Severity Index reduction) were assessed using logistic regression analyses (crude and adjusted for gender, age, psoriatic arthritis and previous treatment). After correction for multiple testing controlling the false discovery rate, six SNPs (IL1B (rs1143623, rs1143627), LY96 (rs11465996), TLR2 (rs11938228, rs4696480) and TLR9 (rs352139)) were associated with response to anti-TNF treatment and 4 SNPs (IL1B (rs1143623, rs1143627), TIRAP (rs8177374) and TLR5 (rs5744174)) were associated with response to ustekinumab treatment (q<0.20). The results suggest that genetic variants related to increased IL-1β levels may be unfavorable when treating psoriasis with either anti-TNF or ustekinumab, whereas genetic variants related to high interferon-γ levels may be favorable when treating psoriasis with ustekinumab.