Antihistamines (AHs) are widely prescribed for allergic conditions and are generally considered safe, with adverse reactions being rare. We report a case highlighting the possible involvement of piperazine ring in a delayed hypersensitivity reaction. A 25-year-old woman with a history of atopic dermatitis progressively developed a maculopapular drug eruption following intake of cetirizine. Patch testing was negative, but oral provocation with cetirizine reproduced the rash, confirming its causal role. Importantly, oral provocation with ciprofloxacin, which also contains a piperazine ring, elicited a similar reaction, supporting that this structural moiety itself was responsible for hypersensitivity. Alternatively, AHs lacking the piperazine ring, such as in bilastine and rupatadine, were well tolerated. This case provides the first direct evidence of delayed hypersensitivity manifesting as a maculopapular drug eruption, probably because of the piperazine ring, with cross-reactivity observed between structurally unrelated drugs. Clinicians should be aware of the potential for structural moiety-driven hypersensitivity to prevent recurrence across different drug classes.

Climate change, pollution, extreme weather events, and ecosystem disruption cause a wide range of consequences for the skin and dermatologic diseases, affecting epidemiology, disease behaviour, and therapeutic response. Some inflammatory dermatoses are worsened by ultraviolet radiation, such as cutaneous lupus and Darier disease. In addition, UV radiation is responsible for most skin cancers. Humidity favours skin infections, particularly fungal infections. Pollution exacerbates atopic dermatitis. Rising temperatures increase sweating, an aggravating factor for fungal infections, Darier disease, and hidradenitis suppurativa. Even some drug-related cutaneous adverse effects are modulated by weather conditions. Several aspects of the dermatological activity contribute to pollution and climate changes, by, for instance, packaging, metabolites and conservatives, UV filters and waste generated by dermatological surgery.

Occupational allergy to rat and mouse in laboratory animal facilities remains underdiagnosed and raises major concerns. This comprehensive review provides an overview of this allergy in literature and recent findings over the last decade. The prevalence of rat and mouse allergy among laboratory workers over the past ten years ranges from 4,4

Benzalkonium chloride (BAK) is an antiseptic that has long been known to be an irritant. In recent years, its allergenicity has been highlighted [1]. This cationic surfactant from the quaternary ammonium family is widely used in the health field, particularly as a skin disinfectant in France in the form of Biseptine [chlorhexidine 0.25%, benzyl alcohol 4%, BAK 0.25%] (Bayer Healthcare, Gaillard, France). We report the case of a 42-year-old woman who had recurring vesicular, eczematous, and itchy lesions on her right forearm for 3 months following a tattoo in the same location. She had a history of contact reactions to dressings without investigation. From the first day of tattooing, the patient developed local skin inflammation with a vesicular reaction attributed to Staphylococcus aureus infection by her general practitioner (GP) (Figure 1). She had no fever. She was treated with amoxicillin-clavulanic acid 3 g/d orally for 14 days, which partially improved her condition. She applied to the skin concomitantly Biseptine and Septivon 1.5% [chlorhexidine] (Perrigo France, Chatillon, France). Due to the persistence of inflammatory skin lesions on her forearm (Figure 1), she continued to apply antiseptics topically several times a day with locoid 0.1% [hydrocortisone-17-butyrate] (Cheplapharm France, Levallois-Perret, France). In the absence of improvement, she was treated a second time by her GP with amoxicillin-clavulanic acid 3 g/d orally for 10 days without success. The skin condition finally improved with Dermoval 0.05% [clobetasol propionate] (GlaxoSmithKline, Rueil-Malmaison, France) locally and oral desloratadine 5 mg/d on the advice of a dermatologist after stopping local antiseptics. A contact allergy to local antiseptics was suspected. We performed patch testing with Biseptine and its components (benzyl alcohol, chlorhexidine, BAK). The reading was done according to the International Contact Dermatitis Research Group criteria. The occlusion time was 48 h according to the European Society of Contact Dermatitis guidelines. The haptens were applied on the back using Finn Chambers. Patch tests were positive for BAK 0.1% aq (+) and Biseptine (BAK 0.25%, chlorhexidine 0.25%, benzyl alcool 4%) aq (++) (Figure 2) at D2. The rest of the substances were negative at D2 and D3. Patient consent was obtained for this article. This case illustrates a vesicular reaction due to an allergy to BAK present in Biseptine. A similar reaction was described with a contact allergy to the topical antibacterials polymyxin B and bacitracin [2]. Only 15 cases of monosensitisation to BAK in case of allergy to Biseptine have been described in the literature [3]. The patient's history of allergy to dressings is likely due to her allergy to BAK, as it may be a component of dressings [4]. BAK allergy is probably underestimated because sensitisation to BAK is not systematically sought. In our case, it is impossible to say whether the very first post-tattoo skin dermatitis was related to Staphylococcus aureus infection or was already due to BAK allergy. The patient did not have bacteriological skin analysis. Regardless, this case shows that it is important to rule out a contact allergy in case of signs of recurring local infection. Juliette Caron: conceptualization, investigation, writing – original draft, methodology, validation, visualization, writing – review and editing, data curation, supervision. Florence Libon: writing – review and editing. Christine Delebarre-Sauvage: writing – review and editing. The authors declare no conflicts of interest.

The treatment of moderate to severe psoriasis relies currently on the use of IL17 and IL23 antagonists. These biological treatments are highly efficacious with an excellent long-term safety profile. Despite the targeted actions of these agents, they are associated with a mild degree of immunosuppression, potentially leading to the reactivation of preexisting infectious diseases, or to an increased susceptibility to infectious diseases or an increased severity and duration of an infectious disease. Hence psoriasis patients receiving biologics must be counseled on recommended vaccinations before initiating a biological therapy or during a biological treatment. In general, for living attenuated vaccinations biologic treatment must be interrupted but for inactivated vaccinations it may be continued. Currently there is no proof that psoriasis patients treated with IL17 or IL23 antagonists present an increased risk for the infections covered by the conventional vaccines and hence the vaccination guidelines should follow the recommendations for the general population.

Allergy to industrial antioxidants has long been considered uncommon, especially to gallates. Only 74 cases of contact allergy to gallates have been reported in the last literature review published in 2017 [1]. Since then, some recent studies suggest that these allergens are not so rare [2]. We report the case of a 68-year-old woman having chronic cheilitis evolving for 10 years. Her history was marked by migraines and dyslipidaemia treated by propranolol and Inegy [simvastatin/ezetimibe] (Organon Heist BV, Heist-op-den-Berg, Belgium) respectively for more than 10 years. Clinical examination showed eczema on the lips. She had daily lip itching. We performed patch testing with the European baseline series and cosmetic series from Laboratoire Destaing. The reading was obtained according to the International Contact Dermatitis Research Group criteria. The occlusion time was 48 h according to the European Society of Contact Dermatitis guidelines. The haptens were applied on the back using Finn Chambers. Positive results were found for gallate mix 1% (+) and propyl gallate 1% (+++) at D3 and D12 and for dodecyl gallate 0.25% (+++) and octyl gallate 0.25% (+++) at D12 only (Figure 2). After 1 month of avoiding cosmetics on the face, a partial regression of the cheilitis was noted. We carried out additional assessment due to persistent symptoms (Figure 1). Inegy is a lipid-lowering therapy containing propyl gallate as an excipient. We performed patch testing with Inegy 30% petrolatum and a negative control. The patch test was found positive for Inegy (+) at D7 (Figure 2). Treatment with Inegy combining ezetimibe 10 mg/simvastatin 40 mg was replaced by ezetimibe 10 mg and simvastatin 40 mg separately. These uncombined tablets do not contain propyl gallate. We also advised the patient to stop consuming industrial food products and foods containing vegetable oils, as she did every day. Following this advice, the patient no longer had cheilitis. She had no symptoms at the clinical visit 3 months later. We concluded that the patient had chronic gallate cheilitis with drug and dietary involvement. In order to treat chronic or recurrent cheilitis, it is important to eliminate an allergy to gallates. This case confirms that patch-test reading at 48 h or 72 h is insufficient to diagnose a sensitization to these molecules, as previously described [3]. We therefore recommend an additional reading between D7 and D15. The treatment is based not only on avoiding cosmetics containing gallates, but also on avoiding medications and foods containing them. The patient's cheilitis worsened when Locapred 0.1% cream [desonide] (Pierre Fabre medicament production, Gien, France) containing propyl gallate was applied on her mouth. It improved after stopping Inegy and following a diet without industrial food products and vegetable oils. Dietary regulation seems to be necessary for healing, as low doses of propyl gallate can be found in olive oil, and also pasta sauce, chewing gum, or peanut butter [4]. Juliette Caron: writing – original draft, conceptualization, writing – review and editing, validation. Florence Libon: writing – review and editing. Christine Delebarre-Sauvage: supervision, validation. The authors declare no conflicts of interest.

Introduction This study explores the current vaccination practices of French general practitioners regarding children with egg allergy. Methods An observational survey was carried out in the North of France using a questionnaire intended for volunteer general practioners. Results Among 93 general practitioners surveyed, the majority (88.9 %) considered egg allergy to be problematic in case of a vaccination. The three most problematic vaccines were those against influenza, yellow fever and measles, mumps and rubella. Discussion Egg allergy may represent an obstacle to children vaccination. We submit recommendations for vaccination practices.

Background: Biological therapies, including TNF-alpha, IL12/23, IL17 and IL23 antagonists, adequately control a very high number of patients with moderate-to-severe psoriasis with an excellent long-term safety profile. However, on occasion, patients on biological therapy with stabilized disease or complete remission report episodes of sudden breakthrough psoriasis. Aim: To study prospectively in a monocentric tertiary setting, the clinical characteristics of patients presenting a sudden breakthrough psoriasis although completely stabilized (PASI 90-100) under biological therapy. Materials and Methods: Psoriasis patients treated by biological therapies achieving PASI 90-100 and with stabilized disease for at least 6 months were invited to enter the follow-up study for 5 years. The clinical features of patients presenting a breakthrough psoriasis were described as well as the rescue therapies and outcomes. Results: From the total cohort of 1121 patients with psoriasis receiving biologicals, 985 patients responded to the inclusion criteria. After 5 years, 10/882 cases (1,13%) of breakthrough psoriasis were identified. Two cases were induced by the K & ouml;bner phenomenon and 8 cases by severe psychological stress. Rescue therapies included topical very potent corticosteroids or additional injections of the biological. Two patients recovered spontaneously when the stressful event was resolved. In none of the cases, there was a consistency between the breakthrough event and the next scheduled injection, nor the duration of the exposure to the treatment. No biological class or agent could be systematically incriminated. Conclusion: Breakthrough psoriasis is an exceptional event among patients with stabilized psoriasis using biologicals, either triggered by the K & ouml;bner phenomenon or by severe psychological stress. The pathogenesis of the breakthrough events could be linked to stress- or K & ouml;bner-related immunomodulation, permitting breakthrough psoriasis lesions to appear.

Atopic dermatitis (AD) is a chronic inflammatory skin condition. The pathogenesis involves genetic, environmental, and immunological factors as well as a barrier dysfunction of the epidermis. Biomarkers may play a significant role in diagnosis, severity assessment, and treatment monitoring of AD. They are categorizable into diagnostic and prognostic as well as severity and stratification biomarkers, offering the potential for a more personalized treatment approach. Although there have been tremendous therapeutic advancements with interleukin (IL) antagonists and Janus kinase (JAK) inhibitors, the domain of biomarkers still requires further research to clarify their place in the diagnosis and prognosis of AD to unravel a better scientific basis for personalized medical care for patients with AD. This article reviews the various biomarkers in relation to the different AD phenotypes and endotypes.

AbstractScabies is a very common ectoparasitosis and is responsible for a real scourge worldwide. The infestation leads to a highly contagious and pruritic dermatosis. Clinical diagnosis is not always easy; dermoscopy is a very useful diagnostic tool. Treatment relies on hygienic measures and specific acaricidals, either for topical application or oral administration. Ivermectin, permethrin and benzyl benzoate are the most frequently used therapies. Treatment failure is on the rise and could be attributed to noncompliance, treatment costs or to resistance to these agents. A series of novel agents are currently under investigation.

The therapeutic prospects for patients with moderate to severe atopic dermatitis completely changed in 2017 with the arrival of the first targeted therapy, dupilumab. Achieving important clinical improvement scores are now possible with this monoclonal antibody directed against interleukins 4 and 13. Since that time, other agents such as tralokinumab arrived on the market, but also the small molecules called «JAK inhibitors» (upadacitinib, baricitinib, etc.). This article provides an inventory of the existing or imminent therapeutic options for atopic dermatitis.

Köbner's phenomenon and its related phenomena are dermatological curiosities that are still partially misunderstood. The Köbner phenomenon is by far the best known and the most studied. It is characterized as the appearance of an inflammatory or infectious dermatosis in an area of healthy skin after skin trauma. The dermatoses most frequently concerned are psoriasis, lichen planus and vitiligo. The inverse Köbner phenomenon and the Renbök phenomenon are two very similar phenomena. The first represents the disappearance of a skin lesion after skin trauma. The second is characterized by a skin trauma that is more specifically induced by another dermatosis. Finally, the Wolf's isotopic phenomenon corresponds to the appearance of a new dermatosis on an area of the skin that was previously the site of another healed dermatosis.

Recently, brentuximab vedotin (BV) (Adcetris®) obtained the reimbursement in Belgium for the treatment of the primary cutaneous NKT-cell lymphomas mycosis fungoides (MF), large cell anaplastic lymphoma and lymphomatoid papulosis type A. BV is a monoclonal antibody directed against the CD30 expressed on tumoral T cells. The inhibition of this pathway releases the process of apoptosis leading to the cell death of the tumoral cells. BV is reimbursed after the use of another systemic treatment without success and if the number of CD30 positive atypical T-cells is larger than 10 %. BV is administered intravenously every 3 weeks with a dosing of 1,8 mg/kg with a maximum of 16 courses. The response rates exceed 75 %. In some instances, interesting treatment responses have been observed with BV in CD30 negative patients. The principal adverse effects are neutropenia and peripheral neuropathy. Two patients are presented with longstanding multi-resistant MF that were successfully treated with BV.

Introduction Psoriasis affects around 2% of children in Europe. The majority of cases is readily managed with topical treatments using corticosteroids without or with calcipotriol. More resistant and extensive moderate-to-severe cases require UVA or UVB phototherapies or conventional systemic treatment including ciclosporin, acitretin and methotrexate. However, these therapies are associated with a low tolerability and potential cumulative long-term adverse effects and toxicities. Areas covered About 15 years ago, the first biological appeared for the treatment of moderate-to-severe plaque type psoriasis in adult patients. Several years later, the first biologic treatment to be approved in children was etanercept, a soluble receptor that binds both tumor necrosis factor (TNF)-alpha and beta followed by adalimumab, a monoclonal antibody against TNF-alpha, and currently by ustekinumab, a monoclonal IL12/23 p40 antagonist and, very recently, secukinumab and ixekizumab, both IL17 antagonists. All these biologic treatments brought significantly improved treatment results compared to light-based therapies and conventional treatments and present very good tolerance and safety profiles. Expert opinion Due to their excellent efficacy and safety profiles ustekinumab, secukinumab and ixekizumab could currently be considered as a first-line treatment options for moderate-to-severe childhood and adolescent psoriasis requiring a systemic treatment.