Intradermal Method Research Articles

Knowledge, Attitude, and Practice of Antibiotic Allergy Testing Among Nurses in Sulaimani, Iraq

Background: One of the major causes of iatrogenic mortality and morbidity is drug allergy. Drug allergies continue to be a major problem for medical professionals right now. For the precise diagnosis of both immediate and delayed medication hypersensitivity, intradermal sensitivity testing is crucial.Objectives: to assess the nurse’s knowledge, attitude and, practice on intradermal method of antibiotic sensitivity test in Sulaimani, Iraq.Materials and Methods: A quantitative, descriptive, and observational design was used to collect information from nurses at Shar Teaching Hospital from various hospital departments. A convenient sampling method was employed for all 90 nurses from January 2022 to August 2022. Data collection was carried out through a structured interview questionnaire aimed at gathering the nurses’ general characteristics, a nurses’ knowledge questionnaire, and an observational checklist to assess the nurses’ practices regarding the Antibiotic Allergy Test.Results: The results indicated a positive attitude and a moderate knowledge of the antibiotic allergy test. A significant correlation existed between attitude scores and age (p=0.03) and degree (p=0.01) but not between demographic characteristics and general knowledge (p>0.05). However, prior research revealed a significant correlation between knowledge and attitude and the training program.Conclusion: The knowledge and attitude of nurses about intradermal testing were moderate. To help nurses better comprehend and fill in the gaps in the practice of antibiotic allergy testing, extensive training and education are therefore required.

Comparative diagnosis of bovine tuberculosis using single intradermal cervical tuberculin technique, conventional methods, enzyme-linked immunosorbent assay, and the gamma-interferon assay.

Background and Aim:Bovine tuberculosis (TB) is a zoonotic disease that causes huge economic losses. This study aimed to compare the result obtained from the single intradermal test, conventional methods (culture and microscopy), gamma-interferon (IFN-γ) assay, and indirect enzyme-linked immunosorbent assay (ELISA) to diagnose bovine TB.Materials and Methods:This study evaluated 2913 animals from milk farms in Cairo, El-Sharkia, and El-Qalyubia Governorates by single intradermal cervical tuberculin technique (SICTT), ELISA, and IFN-γ assay.Results:Of the 2913 dairy cows surveyed, 3.7% yielded positive results. Culture prepared samples on Lowenstein-Jensen and Middlebrook 7H10 agar media yielded 52 (1.85%) isolates of Mycobacterium spp. from 2805 milk samples that yielded negative tuberculin reactions and 56 (51.85%) isolates of Mycobacterium spp. were recovered from 108 lymph node samples from positive cases. ELISA analysis of the sera of 108 positive SICTT reactors revealed that 94 (87.03%) and 97 (89.81%) animals were positive for bovine purified protein derivative (PPD-B) antigen and commercial polypeptide antigen, respectively. IFN-γ assays were performed on whole blood samples collected from positive SICTT reactors and showed that 103 (95.37%) animals were positive.Conclusion:M. tuberculosis complex may be isolated from raw milk and not all infected animals shed mycobacterial bacilli in their milk. The use of polypeptide antigen in ELISA provides better diagnostic efficacy than PPD-B antigen. The IFN-γ assay is more sensitive than both SICTT and ELISA. It should be used in parallel with SICTT to allow the detection of more positive animals before they become a source of infection to other animals and humans.

Evaluation of Behavioral Aspects after Intradermal and Intramuscular Vaccine Application in Suckling Piglets

The aim of this study was to analyse the behavioral aspects of suckling piglets after an intradermal vaccination method in comparison to an intramuscular vaccination applied on the seventh day of life. Possible effects on piglet welfare should be evaluated. Under field conditions, 135 suckling piglets from 12 litters were vaccinated against Mycoplasma hyopneumoniae—64 of those intradermally and 71 intramuscularly, from six litters each. For behavioral analyses, videos were recorded per pen, starting three days before the vaccination and ending three days after the vaccination. In the video analyses, the observation periods 6.00–10.00, 13.00–17.00, and 19.00–21.00 were analysed via scan sampling for the behaviors lying, standing, walking, suckling, and social contact. In the behavioral observations, in all piglets, the most frequent behavior was lying, followed by suckling at the sow’s teats. After vaccination, less lying behavior and more suckling behavior were assessed in intradermally vaccinated piglets compared to intramuscularly vaccinated piglets, which indicates that the piglets were not impaired by stress following vaccination. The results of this study showed that intradermal needle-free vaccination has clear advantages, as it caused fewer vaccination-associated behavior changes in suckling piglets than the intramuscular vaccination method with a needle.

Regenerative potential of partially differentiated mesenchymal stromal cells in a mouse model of a full-thickness skin wound.

Mesenchymal stromal cells (MSCs, known as mesenchymal stem cells) are considered to be a promising therapeutic tool for many diseases. But it is still unclear which cells are more efficient and safe for wound healing and tissue regeneration for clinical applications: undifferentiated, partially differentiated stem cells or differentiated cells. In this study, we modified MSCs with keratinocyte-conditioned medium (KCM) and examined MSCs, partially differentiated MSCs (PMSCs) and differentiated cell migration, accumulation in the wounded area as well as cell regenerative efficiency in a full-thickness skin wound model. In addition to that, the impact of intradermal and intravenous cell delivery methods of wound healing was evaluated. C57BL/6J mouse compact bone MSCs were treated with a KCM for 14 days. Flow cytometry analysis showed the appearance of keratinocyte surface markers which were absent in MSCs, whereas the specific markers for MSCs were lost. Cells were injected either intravenously or intradermally in C57BL/6J mice. Wound closure, cell migration and accumulation in the wounded area were further analysed. Wound healing was assessed by the rate of wound closure and by histological evaluation. Cells were monitored using optical imaging. We demonstrated that PMSCs showed morphology similar to keratinocyte cells, had enhanced migration and increased survival at the site of injury. PMSCs had a beneficial effect on wound healing and tissue regeneration. This effect was reinforced when these cells were injected intravenously. Due to their partial differentiation status, we assume that PMSCs can differentiate more rapidly into epidermal cell lineages thus causing faster and qualitatively improved wound healing.

A study on BCG vaccination using bifurcated needle in babies.

Investigation was done on 527 babies comparing BCG vaccination by bifurcated needle and intradermal method. For this study Japanese and Biofarma BCG vaccines were used.

METHODS OF CONTROL DIPHTHERIA VACCINE SAFETY

Vaccination success depends not only on the timely coverage of threatened contingents, but also on the quality of vaccines. Every day, the requirements for security guarantees vaccines and their use guarantees of security increases. For the fast, reliable and independent scientific assessment of vaccine safety issues, WHO in 1999 created the Global Advisory Committee on Vaccine Safety. To enhance the capacity of pharmaceutical supervision in relation to vaccines in 2012 it was developed the Global Vaccine Safety Initiative. The main directions of the Global Vaccine Safety programs are considered in this review. It’s noted more strict requirements of Ukrainian pharmaceutical industry to produce public immunization drugs regulated Supplements to the State Pharmacopoeia of Ukraine, in comparison with other countries. This review considered diphtheria vaccine safety monitoring in the process of production according to the recommendations of the World Health Organization (WHO), described a subcutaneous method for determining the specific toxicity of the combined purified toxoid, characterized an intracutaneous method of determining of the presence of diphtheria toxin in each sample of the combined purified toxoid, that additionally used by some manufacturers. The definition of diphtheria toxin in dilutions of purified toxoid is presented. This review considered diphtheria vaccine safety monitoring in the process of production according to the recommendations of the World Health Organization (WHO), described a subcutaneous method for determining the specific toxicity of the combined purified toxoid, characterized an intracutaneous method of determining of the presence of diphtheria toxin in each sample of the combined purified toxoid, that additionally used by some manufacturers. The definition of diphtheria toxin in dilutions of purified toxoid is presented. As methods for determination of diphtheria toxin must be able to detect even a small amount of toxin it's examined the WHO's proposal to use an intradermal method on guinea pigs and tests on cell cultures. Attention is drawn to the fact that the determination of specific toxicity in cell culture can be carried out at presence of the approval of this method of a national control authority and sensitivity rates no less than in experiments on guinea pigs. The determining of specific toxicity of ready vaccine by subcutaneous method is described. The publication gave a test for elevated toxicity of the final product by intraperitoneal infection of mice and guinea pigs. It’s cited the WHO recommendations aimed at removing the possibility of recovery of the refined toxin toxicity. Checking vaccines toxicity, pyrogenicity, sterility, allergenicity, teratogenicity, mutagenicity and immunogenicity mainly performed on laboratory animals. The review examined the unreliability of animal experiments and the need to find alternative methods for determining the toxicity without their use particularly in light of the “3R”concept. Methods for determining diphtherial toxin using cell cultures is considered, namely, colony overlay test (COT), tests using a monolayer of HeLa cell culture, a culture of Vero cells (kidney cells of african green monkeys ), a culture of CHO cells (cells of Chinese hamster ovary), which are based on the toxin cytopathic effect on sensitive cell culture. Their advantages and disadvantages are listed. An alternative method for the quantitative detection of C. diphtheriae toxin using the polystyrene plate coated with monoclonal antibody to the part of the diphtheria toxin which defines its binding to the cell, is described. It’s regarded the cytotoxic effect of diphtheria toxin on cells of the immune system of mice and guinea pigs: splenocytes, adhesive phagocytes i B- lymphocytes.

Anaphylactic augmentation by epicutaneous sensitization to acid-hydrolyzed wheat protein in a guinea pig model

Recent reports suggest that hydrolyzed wheat protein (HWP) variants such as Glupearl® 19S (GP19S) induce immediate-type hypersensitivity via epicutaneous (EC) sensitization. The identification of strong allergens is a key step in product assessment before commercial launch. However, few reports have described the estimation of actual and potential anaphylactic sensitizing capacity. In this study we assessed the strength of both the actual and potential anaphylactic sensitizing capacity by investigating the immediate-type hypersensitivity inducing potential of HWP compared with gluten. We assessed these strengths via the EC route using an EC or intradermal (ID) sensitization method. We quantified the strength of immediate-type hypersensitivity by evaluating the titer of serum antibodies isolated from sensitized subjects using passive cutaneous anaphylaxis (PCA) reactions. We also evaluated the cross-reactivity between GP19S and gluten. GP19S and gluten applied by both the sensitization methods induced obvious IgG1-mediated PCA reactions. GP19S had stronger sensitizing potential than gluten, according to the serum titers and dye spot diameters. The difference in antibody titers between GP19S and gluten was 16-fold for the EC method versus 2-fold for the ID method. GP19S cross-reacted with gluten. Acid hydrolysis of gluten increased anaphylactic sensitizing capacity in the EC method. To our knowledge, our study is the first to quantitatively confirm that HWP and gluten can induce immediate-type hypersensitivity through an intact skin. These findings suggest that acid-HWP imposes a higher risk of EC sensitization than gluten because of the ease with which the former confers a sensitizing effect through the intact skin.

Breaking the Barriers to Access a Low Cost Intra-Dermal Rabies Vaccine Through Innovative “Pooling Strategy”

Background: In India every year an estimated 20,000 patients die of Rabies. Major reason for poor compliance to anti-rabies prophylaxis is the high cost of anti-rabies vaccine being prescribed intramuscularly (IM) as a routine i.e. 44.5 USD per course of five injections. In 1992 WHO recommended low cost intra-dermal rabies vaccination (IDRV), which costs only 7.5 USD or less per animal bite course. Methods: Interviews with doctors revealed that they were not prescribing intra-dermal anti rabies vaccination as they were either not aware or were not confident of this route of rabies vaccination. Also the vaccine vial did not have the label for “intra-dermal use”. These barriers were removed by advocacy efforts with policy makers & drug companies, credit sharing & team building, which led to starting of first intra dermal anti-rabies clinic of North India on 2nd August 2008. Results: Within a month of start of intra-dermal rabies vaccination clinic, i.e. by 2nd September, 2008, there was an increase in the hospital patient load by 2.8 times, and poor patients load by 3.2 times. In just less than two-year time, 200,000 USD of poor patients were saved and 5769 patients vaccinated. Each patient was asked to bring one vial on first visit & rest of doses were given “free” by pooling strategy. Pooling strategy involved distribution of one vial of vaccine among four persons and keep the three vials for use one by one by all the four patients on subsequent three visits. Another offshoot of the strategy was to prevent wasting of even few drops of vaccine that used to remain in each vial of 1 ml after distribution among four patients (0.2 mL or less). Out of more than 5000 vials utilised, every time we would transfer the left out drops of vaccine to the next new vial and use it immediately on a new pool of patients waiting for vaccination. We would, however, discard the unused vaccine after eight hours of reconstitution at the end of the day. The vaccine so saved turned to be a stock of more than 100 vials in less than two years that we were able to give free to more than 225 rag pickers, garbage collectors and newspaper hawkers on World Rabies Day, Sep 28, 2010. Conclusions: With intra-dermal clinic, we were able to successfully introduce the new cost effective intra-dermal method of rabies vaccination despite all odds & vested interests of companies & old mindset of doctors that had blocked this technique till now. This will go a long way in reducing the burden of disease & death due to rabies from India.

Rabies vaccination for international travelers

Rabies prevention in travelers is a controversial issue. According to experts, the decision to vaccinate results from an individual risk assessment based on the duration of stay, the likelihood of engagement in at-risk activities, the age of the traveler, the rabies endemicity and access to appropriate medical care in the country of destination. However, no detailed information is available regarding the last two determinants in many regions. Twenty-two cases of rabies were reported in tourists, expatriates and migrant travelers over the last decade, including three cases following short-term travel of no more than two weeks. Studies on rabies post-exposure prophylaxis (PEP) in travelers show that overall, 0.4% (range 0.01-2.3%) of travelers have experienced an at-risk bite per month of stay in a rabies-endemic country, while 31% of expatriates and 12% of tourists were vaccinated against rabies before traveling. The main reason cited by travelers for not being vaccinated is the cost of the vaccine. The majority of patients who sustained a high risk injury was not vaccinated against rabies before traveling and were not properly treated abroad. From available studies, the following risk factors for injuries sustained from potentially rabid animals may be identified: traveling to South-East Asia, India or North Africa, young age, and traveling for tourism. The duration of travel does not appear to be a risk factor. It should be noted that "at-risk activities" have not been addressed in these studies. Detailed rabies distribution maps and information on the availability of rabies biologics are urgently needed in order to identify those travelers who need pre-travel vaccination. Meanwhile, cost-minimization of rabies pre-exposure vaccination may be achieved in several ways, notably by using the intra-dermal method of vaccination.

A specific skin test: the best for both worlds?

For a new tuberculin skin test (TST) to be considered useful, it must meet several requirements including safety, a readable skin response, affordability, a high predictive value, and it cannot easily sensitize, depend on patient characteristics, nor depend on the Mycobacterium tuberculosis isolate. After review of previously conducted animal model studies, we designed a double-blind randomized Phase 1 study comparing recombinant dimer ESAT-6 (rdESAT-6, Statens Serum Institut, Copenhagen, Denmark) to tuberculin as a skin test reagent in the diagnosis of TB. The goals of the study were to assess the safety of an intradermal method of administering the test and to determine the appropriate human dose. The study compared the administration of 2.0 TU PPD (standard dose of RT 23) to four doses of rdESAT-6 (0.01, 0.1, 1, and 10μg). The protocol also called for intra-subject randomization of the left and right forearm. Participants were enrolled in eight different groups. Four groups comprised five healthy controls each for the purpose of testing safety and sensitization issues. The other four groups comprised patients who had been treated for TB in order to determine safety and optimal dose. Several exclusion criteria were applied, including individuals who had received a TST test within the past year or had a known immune deficiency. During the 28-day trial, the guidelines called for 2 hours of close observation after administering the test on Day 0; clinical parameters, photography on Days 1 to 4 with quantiFERON testing of control subjects on Day 2 and lab and urine tests on Day 4; diary keeping on Days 5 to 28 with physical exam, lab and urine tests on Day 28 and quantiFERON testing of control groups. In control groups, all four dosages of rdESAT-6 were administered with no serious side effects; transient redness occurred at 24 hours at the 10 μg dose; and no indication of sensitization was measured in vitro. In the treated TB group, only doses of 0.01 and 0.1 of rdESAT-6 were well-tolerated; equivalent responses to PPD and 0.1 μg rdESAT-6 were observed. Participants reported significant local side effects at 1 μg of rdESAT-6. Results indicate that the new skin test is safe, produced a readable skin test response, did not easily sensitize, and is robust in all practical aspects. Further studies must be conducted on subjects ranging from individuals with active and latent TB, children, pregnant women, and patients who are immunocompromised.

Experience with intradermal injection and intradermal-plus-deep injection in the radioguided sentinel node biopsy of early breast cancer patients

Aims Methods of administering 99mTc-phytate during sentinel node biopsy of early breast cancer patients were compared to improve the sensitivity of the technique. Methods Two injection methods, intradermal vs. intradermal-plus-deep injection, were compared in 648 early breast cancer patients. Intradermal injection was done in 323 consecutive patients (325 breasts), and intradermal-plus-deep injection was done in 325 consecutive patients (329 breasts). The following items were compared: (1) The number of axillary nodes detected scintigraphically and removed surgically, and the breast number of micrometastasis to axillary nodes; (2) The number of internal mammary nodes detected scintigraphically and removed surgically; and (3) The sensitivity of axillary SNB. Results The number of axillary nodes scintigraphically detected was 1.63 ± 0.80 (mean ± SD) in patients given intradermal injection, and was 1.82 ± 0.94 in patients given intradermal-plus-deep injection. The number of axillary nodes surgically removed was 1.78 ± 0.93 in patients given intradermal injection, and was 1.95 ± 0.99 in patients given intradermal-plus-deep injection. The visualization of internal mammary nodes was superior with intradermal-plus-deep injection (5/325 for intradermal, and 51/329 for intradermal-plus-deep). The putative sensitivity was 71/72 (98.6%) for the intradermal-plus-deep method and 56/62 (90.3%) for the intradermal method. The frequency of detection of micrometastasis was 24 in 71 true positive (38.8%) for the intradermal-plus-deep method and 13 in 56 true positive (23.2%) for the intradermal method. Conclusions The SNB procedure with the intradermal-plus-deep injection method detected more axillary and internal mammary nodes, more (not statistically significant) micrometastasis and improved the putative sensitivity more than the SNB procedure with the intradermal injection method.

Role of intradermal skin tests in the evaluation of clinically relevant respiratory allergy assessed using patient history and nasal challenges

Skin testing, correlated with patient history, is the accepted method of identifying clinically relevant aeroallergen sensitivity. Traditionally, intradermal tests are believed to be more sensitive in identifying aeroallergen sensitivity than the epicutaneous and percutaneous methods. Therefore, many allergy practitioners use the epicutaneous or percutaneous method first and, if the results are negative, follow up with intradermal tests. To compare the epicutaneous, percutaneous, and intradermal methods to determine their sensitivity to patient history and to evaluate the value of intradermal tests when epicutaneous and percutaneous test results are negative. Participants were evaluated for rhinoconjunctivitis symptoms and then were skin tested using the prick and Multi-Test II (MTII) methods. Intradermal tests were performed when prick and MTII test results were negative to an aeroallergen. Participants with negative prick and MTII test results and corresponding positive intradermal test results underwent nasal challenges with evaluation by anterior rhinomanometry. Compared with patient history, average sensitivity for MTII was 77% and for the prick method was 62%. When MTII results were negative, 17% of intradermal tests corresponded with probable patient histories of allergy but none with positive nasal challenge results. Nasal challenge results were similar to those of the negative control group and significantly different from those of the positive control group (P < .001). The MTII tests are more sensitive and equally specific compared with the prick method. When MTII results are negative, positive intradermal test results are unlikely to identify clinically relevant aeroallergen sensitivity. Routine performance of intradermal tests when MTII results are negative is likely to be of low clinical yield.

Prevalence and determinants of mastitis and milk-borne zoonoses in smallholder dairy farming sector in Kibaha and Morogoro districts in Eastern Tanzania.

SummaryA study was carried out to establish the prevalence and determinants of mastitis and milk‐borne zoonoses in smallholder dairy farms in Kibaha and Morogoro districts (Tanzania). A total of 57 herds comprising 114 milking cows in Kibaha and 48 herds consisting of 96 milking animals in Morogoro were included in the study. A questionnaire survey was used to assess the socio‐economic determinants of mastitis, whereas California mastitis test (CMT) and microbiological assessment of milk was carried out to establish the status of mastitis and responsible aetiological agents. Seroconversion for brucellosis was evaluated using enzyme‐linked immunosorbent assay (ELISA). Animals were also tuberculin‐tested using a single comparative intradermal method and milk samples were cultured for isolation of Mycobacterium species. Based on CMT, the cow‐based prevalence of subclinical mastitis was 82.4% in Kibaha and 62.4% in Morogoro. Of the 919‐quarter milk samples cultured, 8.2% were positive for aerobic bacteria with predominant isolates being Staphylococcus epidermidis (2.8%), Staph. aureus (1.7%), Streptococcus agalactiae (1.2%) and Staph. intermedius (1.1%). There was a strong association between CMT positivity and bacteriological isolation [relative risk (RR) = 2.60; P = 0.02]. Fungal growth was observed in 21.8% (n = 881) of the samples and the isolates were yeast (19.2%), Mucor (2.5%) and Aspergillus (0.1%). Bucket feeding of calves was associated with increased risk of a quarter being CMT positive (RR = 1.24; P = 0.000), while residual calf suckling was associated with decreased risk of positivity (RR = 0.86; P = 0.015). Earth floor was associated with increased risk of CMT positivity at quarter level (RR = 1.13; P = 0.041) and Jersey breed was identified as a risk factor to mastitis. The prevalence of bovine tuberculosis was 0.4% (n = 259) and 1.7% (n = 181) in Kibaha and Morogoro, respectively. Similarly, the prevalence of brucellosis was 1% (n = 208) in Kibaha and 1.9% (n = 104) in Morogoro. Findings from this study have demonstrated a high prevalence of subclinical mastitis and existence of health risks to milk consumers despite the low prevalence of tuberculosis and brucellosis in the study herds.

Percutaneous or intradermal BCG vaccine?

To compare the intradermal and percutaneous routes of BCG administration. A review of the literature published between 1987 and 2002 was carried out in the MEDLINE and Lilacs databases. The following key words were used: BCG vaccine/administration, adverse effects, efficacy, tuberculosis/prevention and control. Some articles published before 1987 were included because of their relevance to the topic. There are no clinical studies comparing the efficacy of intradermal and percutaneous BCG. Percutaneous BCG causes a weaker reaction, however it is also less efficient in stimulating gamma-interferon production by Th1-lymphocytes, which is considered as the best marker of the anti-tuberculin immune response. In vivo and in vitro studies suggest a better immune response with intradermal BCG. The intradermal method should be recommended for BCG administration.

Intradermal needle method

Intradermal needle method

Administration of the BCG vaccination using the multipuncture method in schoolchildren: a comparison with the intradermal method

BACKGROUNDBCG vaccination using the multipuncture device (the Heaf gun) is recommended in the UK for infants and very small children only. The aim of this study was to investigate the...

Route of administration of BCG in a school population outcome of an audit of clinical practice in North Bedfordshire

Following findings of variations in policies and practices of BCG (Bacillus Calmette-Gúerin) administration in different parts of England and Wales, recommendations were made for BCG vaccination to be administered intradermally using disposable equipment. Intradermal methods were used for BCG in Bedfordshire until 1981 but it was changed in 1982 to percutaneous method using the reusable modified heaf gun. Suggestion to revert from percutaneous to intradermal method caused anxiety amongst health professionals with anecdotal reports of scar formations and keloids causing disfigurement at injection site. An audit was therefore carried out to assess the outcome of intradermal BCG administration initially by doctors and then by nurses. The outcome did not justify initial anxieties.

Route of administration of BCG in a school population: outcome of an audit of clinical practice in North Bedfordshire

Following findings of variations in policies and practices of BCG (Bacillus Calmette-Gúerin) administration in different parts of England and Wales, recommendations were made for BCG vaccination to be administered intradermally using disposable equipment. Intradermal methods were used for BCG in Bedfordshire until 1981 but it was changed in 1982 to percutaneous method using the reusable modified heaf gun. Suggestion to revert from percutaneous to intradermal method caused anxiety amongst health professionals with anecdotal reports of scar formations and keloids causing disfigurement at injection site. An audit was therefore carried out to assess the outcome of intradermal BCG administration initially by doctors and then by nurses. The outcome did not justify initial anxieties.

The Human Capsaicin Model of Allodynia and Hyperalgesia: Sources of Variability and Methods for Reduction

Intradermal and topical application of capsaicin have been used to study mechanisms of mechanical allodynia (MA) and pinprick hyperalgesia (PPH) and the efficacy of drugs in relieving these symptoms. However, it is associated with significant inter- and intra-subject variability. In order to improve the model’s sensitivity, we examined several potential sources of variability of capsaicin-evoked MA and PPH in healthy volunteers, including skin temperature fluctuations, method (intradermal vs. topical) and site (volar forearm vs. foot dorsum) of administration. In study I, 12 subjects received, in a 6-session, randomized, crossover trial, 1) 250 μ g of intradermal (ID) CAP to the volar forearm with skin temperature fixed at 36°C (36 ID). 2) 250 μ g ID CAP with varying skin temperature (VT ID), or 3) 250 μ l of 1% CAP patch placed on the skin at 36°C. The resulting MA and PPH areas observed with each method were measured. In study II, a 4-session, randomized crossover trial, 12 subjects were given 100 μ g ID CAP in the volar forearm or foot dorsum and subsequent areas of MA and PPH recorded. In study I, 5/12 subjects had small MA areas (≤ 5 cm 2) and one subject had small PPH areas in at least 4/6 sessions. The most consistent intra-subject responses were seen with the 36 ID method. Correlation coefficients for the two sessions using the same method of administration were: MA; 36 ID r = 0.83, VT ID = 0.19. Topical r = 0.81; PPH: 36 ID r = 0.93; VT ID r = 0.38, Topical r = 0.78. In study II, 4/12 subjects had little MA for both forearm and foot though all subjects developed PPH. However, greater intra-subject consistency (MA: foot: r = 0.84; arm: r = 0.49; PPH: r = 0.87; r = 0.39) and significantly larger areas of MA (15.8 ± 4.2 vs 9.1 ± 2.5, p < 0.05) were seen with the foot. (PPH: foot: 28.9 ± 6.7; arm: 21.6 ± 4.2, NS). Large variability exists among subjects receiving CAP, with some developing minimal MA. However, these subjects may be screened out prior to entry, increasing the sensitivity of the model, which may be further improved by clamping the skin temperature.

Anaphylaxis to topically applied bacitracin

Background: Bacitracin is widely used for the treatment and prevention of superficial skin infections. Although commonly used, anaphylaxis to topically applied bacitracin is rare, with only nine previously reported cases. Most reported reactions have occurred in middle-aged to elderly women with leg ulcers or chronic eczema. Although most reports include a challenge test to confirm the diagnosis, no recommended standardized method of skin testing for bacitracin anaphylaxis has been advocated to date. Objective: We report two patients who developed anaphylaxis to topically applied bacitracin ointment confirmed by skin prick testing. The subject of bacitracin anaphylaxis is reviewed, and a method for confirmatory skin testing is recommended. Methods: Literature was searched in the MEDLINE database using the key words anaphylaxis and bacitracin, and articles from the American Journal of Contact Dermatitis were also included. Relevant references from these reports were also reviewed. Percutaneous skin prick testing was performed on our 2 patients using the bacitracin powder dilution (10 U/mL and 1 U/mL). Normal control individuals were also tested. Results: Two patients with anaphylaxis to bacitracin are reported. One developed symptoms after a biopsy of chronic eczema was performed. The second patient had no prior history of chronic skin disease and developed symptoms after incurring an abrasion on his knee. The diagnosis was confirmed by a positive wheal and flare reaction after skin prick testing at 1 U/mL and 10 U/mL concentrations, respectively. Normal controls showed no wheal and flare reaction at 10 U/mL. Conclusions: Anaphylaxis to topical bacitracin is rare but potentially fatal. Based on our literature review and the results of our skin testing, we recommend initiating future bacitracin prick testing with 0.1 U/mL. If no reaction occurs at this dilution, subsequent prick testing should be serially performed with a 10-fold higher concentration. Each test should be separated by 15 minutes to a maximum concentration of 10 U/mL. Testing at higher concentrations or by the intradermal method may lead to a false-positive test. This is a US government work. There are no restrictions on its use.