Cold urticaria is a skin condition characterized by rapid appearance of itchy wheals and occasionally angioedema in response to cold stimulation. Antihistamines do not sufficiently protect all patients from symptoms, even when used in higher than standard doses. In these patients, desensitization to cold can be beneficial. The aim was to investigate whether desensitization can lower temperature thresholds and reduce release of histamine in the skin. Cold urticaria patients were subjected to desensitization and assessed for skin responses to cold stimulation and codeine before and after. Histamine levels mediated by cold and codeine were determined by cutaneous microdialysis before and after desensitization in patients and healthy controls. Desensitization to cold resulted in protection from cold-induced symptoms and lower temperature thresholds in six out of nine patients. Desensitization also prevented histamine release after skin exposure to cold. Surprisingly, skin histamine levels and release after codeine injection were found to be normal in desensitized patients.

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Skin microdialysis (SMD) is a versatile sampling technique that can be used to recover soluble endogenous and exogenous molecules from the extracellular compartment of human skin. Due to its minimally invasive character, SMD can be applied in both clinical and preclinical settings. Despite being available since the 1990s, the technique has still not reached its full potential use as a tool to explore pathophysiological mechanisms of allergic and inflammatory reactions in the skin. Therefore, an EAACI Task Force on SMD was formed to disseminate knowledge about the technique and its many applications. This position paper from the task force provides an overview of the current use of SMD in the investigation of the pathogenesis of chronic inflammatory skin diseases, such as atopic dermatitis, chronic urticaria, psoriasis, and in studies of cutaneous events during type 1 hypersensitivity reactions. Furthermore, this paper covers drug hypersensitivity, UVB-induced- and neurogenic inflammation, and drug penetration investigated by SMD. The aim of this paper is to encourage the use of SMD and to make the technique easily accessible by providing an overview of methodology and applications, supported by standardized operating procedures for SMD in vivo and ex vivo. Electronic supplementary material The online version of this article (10.1186/s13601-019-0262-y) contains supplementary material, which is available to authorized users.

RATIONALE: Poorly-controlled asthma is prevalent in the Medicaid Population. Asthma exacerbations are potentially preventable. Primary care providers lack timely data on asthma control status. Outcomes of predictive models depend on an appropriate system of care. METHODS: Parkland Community Health Plan developed a comprehensive intervention including a risk prediction model to define the risk for asthma ED visits or hospitalizations, monthly patient and provider level risk score reports to network providers including patient-level data on risk scores, integrating point of care decision support alerts in the EHR of the largest PCHP provider, and coordinaton of care between PCHP Disease Management and Case Managers, PCP's, and information technology vendors. RESULTS: The intervention included asthmatic children assigned to 17 PCP's caring for about 50% of PCHP members, The risk prediction model had a good accuracy (C-statistic 0.84). Patients were categorized into four risk score levels. Expected ED visit or hospitalization rate was 20%, 10%, 4%, and 1.4%. After introduction of the EHR alert providers increased prescription of controller medication 50% and controller-to-rescue medication orders 57% compared to the prior year. Asthma related ED visit rates decreased by 30% (from 16% to 11%), hospitalization rates by 43% (from 3.44% to 1.97%), and total costs by 40% (from $1285 to $766 per member per year). The asthma medication ratio increased by 15%, from 0.39 to 0.45. CONCLUSIONS: Combination of a predictive model with a care coordiantion system and EHR alerts for asthma patients in a Medicaid HMO resulted in dramatic improvements in outcomes and cost of care.

BackgroundDiagnostic workup of penicillin allergy comprises skin testing with penicillins, and patients are deemed allergic if skin test is positive. However, the literature suggests that skin test-positive patients may be challenge-negative, indicating that the skin test may be falsely positive.ObjectiveTo investigate real-time histamine release from a positive intracutaneous test induced by penicillin in patients with positive and negative challenges to penicillin.MethodsSkin microdialysis was performed in 21 penicillin-allergic patients with positive skin test, 13 non-allergic volunteers serving as negative controls, and 7 grass pollen-allergic patients serving as positive controls. Histamine was measured by microdialysis after skin test with penicillin/grass/NaCl. Penicillin challenge was subsequently performed in 12 of the patients.ResultsOnly 10/21 patients (47.6%) were skin test positive at microdialysis. During microdialysis 13 single intracutaneous tests were positive and histamine was detected in 4/13 occurring in four challenge positive patients. Thirteen/21 patients (61.9%) were deemed allergic to penicillin; eight had positive skin test. Two patients with positive skin test were challenge negative. In grass pollen allergic patients, 7/7 had a positive intracutaneous test to grass and all released histamine in the wheals. All 13 negative controls had negative intracutaneous test to penicillin and no histamine release.ConclusionHistamine was only detected in the minority of positive intracutaneous tests with penicillin in penicillin-allergic patients. Other mediators may be involved.