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PurposeCritically ill patients are vulnerable to penicillin allergy labels that may be incorrect. The validity of skin testing in intensive care units (ICUs) is uncertain. Many penicillin allergy labels are low risk, and validated tools exist to identify those amenable to direct oral challenge. This pilot randomised controlled trial explored the feasibility, safety, and validity of direct enteral challenge for low-risk penicillin allergy labels in critical illness.MethodsConsenting patients with a low-risk penicillin allergy label (PAL) (PEN-FAST risk assessment score < 3) in four ICUs (Melbourne, Australia) were randomised 1:1 to penicillin (250 mg amoxicillin or implicated penicillin) direct enteral challenge versus routine care (2-h post-randomisation observation for each arm). Repeat challenge was performed post -ICU in the intervention arm. Patients were reviewed at 24 h and 5 days after each challenge/observation.ResultsWe screened 533 patients. 130 (24.4%) were eligible and 80/130 (61.5%) enrolled (age median 64.5 years (interquartile range, IQR 53.5, 74), PEN-FAST median 1 (IQR 0,1)), with 40 (50%) randomised to direct enteral challenge. A positive challenge rate of 2.5% was identified. No antibiotic-associated serious adverse events were identified. 32/40 (80%) received a repeat challenge (zero positive). Post-randomisation, 13 (32%) of the intervention arm and 4 (10%) of the control arm received penicillin (odds ratio, OR 4.33 [1.27, 14.78] p = 0.019).ConclusionThese findings support the safety, validity, and feasibility of direct enteral challenge for critically ill patients with PEN-FAST assessed low-risk penicillin allergy. The absence of false negative results was confirmed by subsequent negative repeat challenges. A relatively low recruitment to screened ratio suggests that more inclusive eligibility criteria and integration of allergy assessment into routine ICU processes are needed to optimise allergy delabelling in critical illness.

C-Tb, an ESAT-6/CFP-10-based skin test, has similar sensitivity for active TB compared to tuberculin skin test (TST) and QuantiFERON-TB-Gold-In-Tube (QFT). However, data are limited in children and HIV-infected persons. Asymptomatic South African contacts <5 years (n = 87; HIV-uninfected), or symptomatic individuals of all ages presenting to clinics with suspected TB (n = 1003; 30% HIV-infected) were recruited from eight South African centres. C-Tb and TST were allocated to either forearm double blinded. Samples for QFT were collected in parallel, and test-positivity rates were compared. In participants with microbiologically confirmed TB (n = 75; 45% HIV-infected) sensitivity of C-Tb, TST and QFT were similar (72% versus 75% versus 73%; p>0.5). All 3 tests had similar positivity rates in HIV-infected participants with active TB, however, positivity rates were reduced when CD4 counts were <100 cells/μL. In participants where active TB was excluded (n = 920), C-Tb (41%), TST (43%), and QFT (44%) also had similar test-positivity rates. Among asymptomatic contacts aged below five, 32% (28/87) tested positive with C-Tb and 32% (28/87) with TST (concordance 89%). Overall, C-Tb and TST showed a similar safety profile. C-Tb was safe and showed similar test-positivity rates, compared to TST and QFT, in children and HIV-infected persons with active or latent M. tuberculosis infection. These data inform the utility of C-Tb in clinical practice. ClinicalTrials.gov NCT01642888. EudraCT 2011-005078-40.

Background This study aimed to evaluate the diagnostic performance of ESAT6-CFP10 (EC) skin test in healthy population and determine the factors influencing the booster effect. Methods We conducted a randomized, double-blind, parallel controlled trial in healthy population. The experiment was divided into two stages. In the first stage, all participants underwent T-SPOT, TB-PPD, and EC tests. In the second stage, to evaluate whether BCG vaccination affected the efficacy of skin tests, the participants with three negative results in the first stage were randomly assigned to the BCG and placebo groups at a ratio of 2:1 and underwent three tests. The positivity rates and concordance of the three tests were calculated in both stages, and a logistic regression model was constructed to determine the factors influencing the booster effect of EC in the second stage. Safety observations were continued until the skin test results were available. Results In the first stage, 1,564 participants were enrolled in the study. The positivity rates of the T-SPOT, EC, and TB-PPD tests in all the participants were 18.89%, 10.37%, and 53.96%, respectively. The concordance between the EC and T-SPOT tests was 88.97% (kappa = 0.56), and that between the TB-PPD and T-SPOT tests was 58.19% (kappa = 0.20). In the second stage, 585 participants were assigned to the BCG or placebo group. In the BCG group, the positivity rates for the T-SPOT, EC, and TB-PPD tests were 4.76%, 7.30%, and 73.65%, respectively. The concordance between the EC and T-SPOT tests was 94.92% (kappa = 0.55), and that between the TB-PPD and T-SPOT tests was 29.84% (kappa = 0.02). In the placebo group, the positivity rates for the T-SPOT, EC, and TB-PPD tests were 6.88%, 11.88%, and 39.38%, respectively. The concordance between the EC and T-SPOT tests was 91.25% (kappa = 0.49), and that between the TB-PPD and T-SPOT tests was 66.25% (kappa = 0.17). The logistic regression model showed that age ≥ 60 years (odds ratio [OR] = 5.42, 95% confidence interval [CI]: 2.05–14.26) and retest positivity of T-SPOT test (OR = 44.87, 95% CI: 16.58–135.21) were stimulative factors of EC booster effect. Adverse reactions occurred in 168 (10.74%) and 33 participants (5.64%) in the first and second stage, respectively. Most of these were local adverse reactions, including injection site pain, pruritus, and rash. Conclusions The diagnostic performance of the EC skin test was similar to that of the T-SPOT test in the healthy population and was unaffected by BCG vaccination. The booster effects were more inclined to occur in population with retest positivity of T-SPOT or age ≥ 60 years. Clinical trials Registration NCT02795260, Clinical Study of Recombinant Mycobacterium Tuberculosis Allergen ESAT6-CFP10 on Healthy People Aged 18–65(III-healthy), Registration Date: June 10, 2016.

Skin prick test (SPT) is a common test for diagnosing immunoglobulin E-mediated allergies. In clinical routine, technicalities, human errors or patient-related biases, occasionally results in suboptimal diagnosis of sensitization. Although not previously assessed qualitatively, lancet weight is hypothesized to be important when performing SPT to minimize the frequency of false positives, false negatives, and unwanted discomfort. Accurate weight-controlled SPT was performed on the volar forearms and backs of 20 healthy subjects. Four predetermined lancet weights were applied (25 g, 85 g, 135 g and 265 g) using two positive control histamine solutions (1 mg/mL and 10 mg/mL) and one negative control (saline). A total of 400 SPTs were conducted. The outcome parameters were: wheal size, neurogenic inflammation (measured by superficial blood perfusion), frequency of bleeding, and the lancet provoked pain response. The mean wheal diameter increased significantly as higher weights were applied to the SPT lancet, e.g. from 3.2 ± 0.28 mm at 25 g to 5.4 ± 1.7 mm at 265 g (p<0.01). Similarly, the frequency of bleeding, the provoked pain, and the neurogenic inflammatory response increased significantly. At 265 g saline evoked two wheal responses (/160 pricks) below 3 mm. The applied weight of the lancet during the SPT-procedure is an important factor. Higher lancet weights precipitate significantly larger wheal reactions with potential diagnostic implications. This warrants additional research of the optimal lancet weight in relation to SPT-guidelines to improve the specificity and sensitivity of the procedure.

IntroductionPenicillin allergies are highly prevalent in the healthcare setting and associated with the prescription of second-line inferior antibiotics. More than 85% of all penicillin allergy labels can be removed by skin testing and 96%–99% of low-risk penicillin allergy labels can be removed by direct oral challenge. An internally and externally validated clinical assessment tool for penicillin allergy, PEN-FAST, can identify a low-risk penicillin allergy without the need for skin testing; a score of less than 3 has a negative predictive value of 96.3% (95% CI, 94.1 to 97.8) for the presence of a penicillin allergy. It is hypothesised that PEN-FAST is a safe and effective tool for assessing penicillin allergy in an outpatient clinic setting.Methods and analysisThis is an international, multicentre randomised control trial using the PEN-FAST tool to risk-stratify penicillin allergy labels in adult outpatients. The study’s primary objective is to evaluate the non-inferiority of using PEN-FAST score-guided management with direct oral challenge compared with standard care (defined as prick and intradermal skin testing followed by oral penicillin challenge). Participants will be randomised 1:1 to the intervention arm (direct oral penicillin challenge) or standard of care arm (skin testing followed by oral penicillin challenge, if skin testing is negative). The sample size of 380 randomised patients (190 per treatment arm) is required to demonstrate non-inferiority.Ethics and disseminationThe study will be performed according to the guidelines of the Helsinki Declaration and is approved by the Austin Health Human Research Ethics Committee (HREC/62425/Austin-2020) in Melbourne Australia, Vanderbilt University Institutional Review Board (IRB #202174) in Tennessee, USA, Duke University Institutional Review Board (IRB #Pro00108461) in North Carolina, USA and McGill University Health Centre Research Ethics Board in Canada (PALACE/2022-7605). The results of this study will be published and presented in various scientific forums.Trial registration numberNCT04454229.

Background Sensitive skin is a worldwide skin problem, and its assessment of therapeutic efficacy traditionally relies on the facial stinging test. However, this test possesses certain limitations due to its restrictive application site, intense pain sensation, and adverse effects on physical appearance. Objective This study aimed to develop and evaluate a highly efficient and user‐friendly sensitive skin simulation model, which combines tape stripping and capsaicin testing on the forearm (FA‐TS‐CAT), as an alternative to the facial stinging test. Methods A randomized, double‐blind, placebo‐controlled clinical trial was conducted involving 74 subjects. Skin redness (a* value), transepidermal water loss (TEWL), and self‐assessment questionnaires were collected at different time points for analysis. Results Tape stripping 5 times and 10 min application of capsaicin test were identified as the optimal conditions for the FA‐TS‐CAT model. Consistent stimulation and natural recovery trends of a* value and TEWL were observed on both the FA‐TS‐CAT and facial capsaicin test (F‐CAT) models within 50 min. After the 4‐t‐butylcyclohexanol complex emulsion was applied, the a* value in the FA‐TS‐CAT model exhibited a soothing trend similar to the F‐CAT model, with a significantly reduced by 3.99‐fold and 3.28‐fold at T3 and T4 (p < 0.001), compared to the placebo. Notably, the test efficiency of the FA‐TS‐CAT model was threefold higher than that of the F‐CAT model, and subjects showed more willingness to participate in the FA‐TS‐CAT test (95.95% vs. 4.05%). Conclusions These results indicated the FA‐TS‐CAT is a highly efficient and user‐friendly model for sensitive skin, providing a reliable and valid method for clinical research in sensitive skin treatment.

Skin prick test (SPT) and specific IgE (sIgE) are approved for evaluation of allergen sensitization. Local allergen extracts are less expensive and more available but need to be standardized. To compare SPT results of local and imported allergen extracts and sIgE levels in response to the American cockroach, dog, cat, Dermatophagoides pteronyssinus (Dp), Dermatophagoides farinae (Df) and Cladosporium spp. allergens. This prospective, randomized, double-blind, self-controlled study was performed in respiratory allergic volunteers. Each subject was pricked with local and imported allergen extracts and sIgE levels were measured. The agreement between SPT results from each local and imported allergen extract was statistically significant, and the level of agreement for dog allergens was very good (kappa > 0.8). All patients with a positive SPT in response to imported Dp allergen extract had positive SPT in response to local Dp allergen extract. Mean wheal diameter of each allergen in both groups showed significant correlation with sIgE levels. The correlation coefficient (CC) for cat allergens showed a very good-to-excellent relationship (CC> 0.75). When compared with sIgE levels, SPT results for imported and local allergen extracts showed comparable sensitivity, specificity, positive predictive value, negative predictive value, likelihood ratio (LR)+ and LR-. When the SPT results are compared between local and imported allergen extracts, all were found to have significant agreement, with very good agreement for cat allergens. When the SPT results are compared with specific IgE levels, both local and imported allergen extract provided comparable validity.

The role of profilin as an allergen has long been questioned. The capacity of profilin to induce respiratory symptoms has recently been demonstrated; moreover, over 50% of patients sensitized to profilin experienced symptoms after the ingestion of plant-derived foods, suggesting that profilin should be considered as a clinically relevant food allergen. We describe the cases of seven allergic patients with oral allergy syndrome and other adverse reactions after eating plant-derived food, that have been undergone to profilin desensitization treatment. The protocol started with a drop of profilin solution (50 µg/mL) diluted 1:1018 in water until the highest dose of 10 drops of undiluted solution three times a week. At the end of the treatment we observed a decreased mean diameter of profilin wheal in skin prick test (SPT) in five of the seven participants and in profilin specific IgE values in six patients that repeated the test. Regarding basophil activation test (BAT) and the detection of IgG4, we do not have significant results because the tests have to be repeated in some patients. Regarding the double-blind placebo-controlled challenges, after about 10 months of induction phase all the patients showed tolerance to several foods that they previously did not tolerate. Moreover, the immunotherapy with profilin has proved to be safe because no serious adverse events have been reported in our patients. In summary, the results of this exploratory study of sublingual immunotherapy (SLIT) for profilin allergy show that it can be a promising therapeutic option that could modify the clinical reactivity of the patients to the intake of plant-derived food.

New tools are required for the diagnosis of pre-symptomatic leprosy towards further reduction of disease burden and its associated reactions. To address this need, two new skin test antigens were developed to assess safety and efficacy in human trials. A Phase I safety trial was first conducted in a non-endemic region for leprosy (U.S.A.). Healthy non-exposed subjects (n = 10) received three titrated doses (2.5 µg, 1.0 µg and 0.1 µg) of MLSA-LAM (n = 5) or MLCwA (n = 5) and control antigens [Rees MLSA (1.0 µg) and saline]. A randomized double blind Phase II safety and efficacy trial followed in an endemic region for leprosy (Nepal), but involved only the 1.0 µg (high dose) and 0.1 µg (low dose) of each antigen; Tuberculin PPD served as a control antigen. This Phase II safety and efficacy trial consisted of three Stages: Stage A and B studies were an expansion of Phase I involving 10 and 90 subjects respectively, and Stage C was then conducted in two parts (high dose and low dose), each enrolling 80 participants: 20 borderline lepromatous/lepromatous (BL/LL) leprosy patients, 20 borderline tuberculoid/tuberculoid (BT/TT) leprosy patients, 20 household contacts of leprosy patients (HC), and 20 tuberculosis (TB) patients. The primary outcome measure for the skin test was delayed type hypersensitivity induration. In the small Phase I safety trial, reactions were primarily against the 2.5 µg dose of both antigens and Rees control antigen, which were then excluded from subsequent studies. In the Phase II, Stage A/B ramped-up safety study, 26% of subjects (13 of 50) showed induration against the high dose of each antigen, and 4% (2 of 50) reacted to the low dose of MLSA-LAM. Phase II, Stage C safety and initial efficacy trial showed that both antigens at the low dose exhibited low sensitivity at 20% and 25% in BT/TT leprosy patients, but high specificity at 100% and 95% compared to TB patients. The high dose of both antigens showed lower specificity (70% and 60%) and sensitivity (10% and 15%). BL/LL leprosy patients were anergic to the leprosy antigens. MLSA-LAM and MLCwA at both high (1.0 µg) and low (0.1 µg) doses were found to be safe for use in humans without known exposure to leprosy and in target populations. At a sensitivity rate of 20-25% these antigens are not suitable as a skin test for the detection of the early stages of leprosy infection; however, the degree of specificity is impressive given the presence of cross-reactive antigens in these complex native M. leprae preparations. ClinicalTrials.gov NCT01920750 (Phase I), NCT00128193 (Phase II).

The skin prick test (SPT) is a valid and approved tool that is used to diagnose atopic diseases. The SPT is accurate, safe, simple and inexpensive. However, the histamine concentration used as a positive control in the SPT varies among centers. To compare SPT results using different concentrations of locally-prepared and imported histamine solutions. This prospective, randomized, double-blind, self-controlled study was performed in healthy adult volunteers. The SPT was performed using 4 concentrations of histamine solutions (imported, 1 mg/mL; locally-prepared, 1, 5 and 10 mg/mL). Locally-prepared histamine positive controls were prepared from histamine biphosphate monohydrate using sterile technique. Seventy-five adult volunteers (mean age, 36 years) were included in the study. Eight volunteers were male and 9 had a history of atopy. Mean wheal diameter (MWD) for imported histamine was 3.49 mm for a concentration of 1 mg/mL, and that of locally-prepared histamine was 2.94 mm, 5.05 mm and 5.52 mm for concentrations of 1, 5 and 10 mg/mL histamine, respectively. Negative SPT results (MWD <3 mm) were found in 11 subjects (14.7%) who received imported histamine and 26 subjects (34.7%) who received the locally-prepared histamine at concentration of 1 mg/mL. All subjects tested with locally-prepared histamine at concentrations of 5 and 10 mg/mL had a MWD > 3 mm. Locally-prepared histamine base at concentrations of 5 and 10 mg/mL yielded better positive results than both imported and locally-prepared histamine at a concentration of 1 mg/mL.