This update and revision of the international guideline for urticaria was developed following the methods recommended by Cochrane and the Grading of Recommendations Assessment, Development and Evaluation (GRADE) working group. It is a joint initiative of the Dermatology Section of the European Academy of Allergology and Clinical Immunology (EAACI), the Global Allergy and Asthma European Network (GA²LEN) and its Urticaria and Angioedema Centers of Reference and Excellence (UCAREs and ACAREs), the European Dermatology Forum (EDF; EuroGuiDerm), and the Asia Pacific Association of Allergy, Asthma and Clinical Immunology with the participation of 64 delegates of 50 national and international societies and from 31 countries. The consensus conference was held on 3 December 2020. This guideline was acknowledged and accepted by the European Union of Medical Specialists (UEMS). Urticaria is a frequent, mast cell–driven disease that presents with wheals, angioedema, or both. The lifetime prevalence for acute urticaria is approximately 20%. Chronic spontaneous or inducible urticaria is disabling, impairs quality of life, and affects performance at work and school. This updated version of the international guideline for urticaria covers the definition and classification of urticaria and outlines expert‐guided and evidence‐based diagnostic and therapeutic approaches for the different subtypes of urticaria.

Intermittent circadian fasting, namely Ramadan, is a common worldwide practice. Such fasting has a positive impact on psoriasis, but no data exist on its role in psoriatic arthritis (PsA)—a disease that is clearly linked to body mass index. We enrolled 37 patients (23 females and 14 males) with a mean age 43.32 ± 7.81 and they fasted for 17 h for one month in 2016. The baseline PsA characteristics were collected and 12 (32.4%) patients had peripheral arthritis, 13 (35.1%) had axial involvement, 24 (64.9%) had enthesitis, and 13 (35.1%) had dactylitis. Three patients (8.1%) were treated with methotrexate, 28 (75.7%) with TNF-α blockers, and 6 (16.2%) with IL-17 blockers. After a month of intermittent fasting, C-reactive protein (CRP) levels decreased from 14.08 ± 4.65 to 12.16 ± 4.46 (p < 0.0001), Bath Ankylosing Spondylitis Disease Activity Index (BASDAI) decreased from 2.83 ± 1.03 to 2.08 ± 0.67 (p = 0.0078), Psoriasis Area Severity Index (PASI) decreased from 7.46 ± 2.43 to 5.86 ± 2.37 (p < 0.0001), and Disease Activity index for PSoriatic Arthritis (DAPSA) decreased from 28.11 ± 4.51 to 25.76 ± 4.48 (p < 0.0001). Similarly, enthesitis improved after fasting, with Leeds Enthesitis Index (LEI) decreasing from 2.25 ± 1.11 to 1.71 ± 0.86 (p < 0.0001) and dactylitis severity score (DSS) decreasing from 9.92 ± 2.93 to 8.54 ± 2.79 (p = 0.0001). Fasting was found to be a predictor of a decrease in PsA disease activity scores (DAPSA, BASDAI, LEI, DSS) even after adjustment for weight loss. IL-17 therapy was found to be an independent predictor of decreases in LEI after fasting. These preliminary data may support the use of chronomedicine in the context of rheumatic diseases, namely PsA. Further studies are needed to support our findings.

Fasting during the month of Ramadan consists of alternate abstinence and re-feeding periods (circadian or intermittent fasting). Nothing is currently known on the impact of this kind of fasting on psoriasis. A sample of 108 moderate-to-severe plaque psoriasis patients (aged 42.84 ± 13.61 years, 62 males, 46 females) volunteered to take part in the study. A significant decrease in the “Psoriasis Area and Severity Index” (PASI) score after the Ramadan fasting (mean difference = −0.89 ± 1.21, p < 0.0001) was found. At the multivariate regression, the use of cyclosporine (p = 0.0003), interleukin-17 or IL-17 blockers (p < 0.0001), and tumor necrosis factor or TNF blockers (p = 0.0107) was independently associated with a low PASI score, while the use of apremilast (p = 0.0009), and phototherapy (p = 0.0015) was associated with a high PASI score before the Ramadan fasting. Similarly, the consumption of cyclosporine (p < 0.0001), IL-17 blockers (p < 0.0001), mammalian target of rapamycin or mTOR inhibitors (p = 0.0081), and TNF blockers (p = 0.0017) predicted a low PASI score after the Ramadan fasting. By contrast, narrow band ultraviolet light B or NB-UVB (p = 0.0015) was associated with a high PASI score after Ramadan fasting. Disease duration (p = 0.0078), use of apremilast (p = 0.0005), and of mTOR inhibitors (p = 0.0034) were independent predictors of the reduction in the PASI score after the Ramadan fasting. These findings reflect the influence of dieting strategy, the biological clock, and circadian rhythm on the treatment of plaque psoriasis.

Skin serves as the first protective line and barrier of the body. Like many other organs, skin can be affected by several disorders in response to external factors such as pathogens, ultraviolet light, and pollution, as well as endogenous alterations related to aging and/or oxidative stress disturbance. Researchers have reported new insights into how skin cells are altered in response to caloric restriction diets in mammals. One of the most well-known caloric restriction diets is the Ramadan intermittent fasting, which is a radical change in the diet plan of practitioners for the period of one lunar month. Ramadan fasting represents the fourth of the five pillars of the Islamic creed. Even though infirm individuals are waived to take part in this religious duty, patients with various health problems, including those with different skin disorders, might choose to share this event with peers and family members. No standardized protocols or guidelines exist, however, to advise their physicians on the proper management of their patients’ condition during fasting. With an increasing Muslim population living in Western countries, this topic has started to draw substantial attention, not only of Middle-Eastern physicians, but also of clinicians in the West. For this purpose, we carried out a comprehensive overview on the topic. Our main findings are that: (1) there is a strong need for evidence-based suggestions and guidance. Literature on the impact of the Ramadan fasting, as well as of other kinds of fasting, on skin diseases is scarce and of poor quality, as well as the information available from the Internet; (2) patients willing to fast should be advised about the importance of taking proper treatments or consider alternative options including administration of trans-dermal/topical drugs, as they are permitted during daylight hours. Further, non-compliance has important, clinical and economic implications for an effective patient management.

Psoriasis and atopic dermatitis (AD) are chronic inflammatory skin diseases, which negatively influence the quality of life. In the last years, several evidences highlighted the pivotal role of skin bacteria in worsening the symptomatology of AD and psoriasis. In the present study we evaluated the skin microbiota composition in accurately selected subjects affected by (AD) and psoriasis. Three first cousins were chosen for the study according to strict selection of criteria. One subject was affected by moderate AD, one had psoriasis and the last one was included as healthy control. Two lesional skin samples and two non-lesional skin samples (for AD and psoriatic subjects) from an area of 2 cm2 behind the left ear were withdrawn by mean of a curette. For the healthy control, two skin samples from an area of 2 cm2 behind the left ear were withdrawn by mean of a curette. DNA was extracted and sequencing was completed on the Ion Torrent PGM platform. Culturing of Staphylococcus aureus from skin samples was also performed. The psoriatic subject showed a decrease in Firmicutes abundance and an increase in Proteobacteria abundance. Moreover, an increase in Streptococcaceae, Rhodobacteraceae, Campylobacteraceae and Moraxellaceae has been observed in psoriatic subject, if compared with AD individual and control. Finally, AD individual showed a larger abundance of S. aureus than psoriatic and healthy subjects. Moreover, the microbiota composition of non-lesional skin samples belonging to AD and psoriatic individuals was very similar to the bacterial composition of skin sample belonging to the healthy control. Significant differences between the skin microbiota of psoriatic individual and healthy and AD subjects were observed.