Inadequacy of current pediatric epinephrine autoinjector needle length for use in infants and toddlers

Frequencies and predictors of subcutaneous and intraosseous injection with 4 epinephrine autoinjector devices

BACKGROUND

To prevent anaphylaxis-associated illness, intramuscular epinephrine injection is recommended. Subcutaneous injection may reduce efficacy, and intraosseous injection promotes morbidity. A few studies suggested that commercially available thigh epinephrine autoinjectors (EAIs) may induce subcutaneous/intraosseous injection in some adults.

OBJECTIVE

To estimate the subcutaneous/intraosseous-injection rates of 4 EAIs by comparing their needle lengths with the ultrasound-measured skin-to-muscle depth and skin-to-bone depth of the midthigh of adults with allergic diseases in a cross-sectional study and to determine patient factors that predict subcutaneous EAI injection.

METHODS

Thigh ultrasound was conducted in a convenience-recruited cohort with minimal and maximal compression to estimate the effect of EAI-induced compression. Subcutaneous/intraosseous-injection rates were estimated for Anapen (BioProject), EpiPen (Mylan), Jext (ALK), and Emerade (Medeca). Multivariate analyses for subcutaneous-injection risk were conducted with age, male/female sex, abdominal and thigh circumferences, and upper-arm skinfold thickness.

RESULTS

A total of 68 patients were recruited. Compression thinned the subcutaneous tissue and muscle by 1 and 9 mm, respectively, on average. Projected subcutaneous-injection rates with/without compression were high for Anapen (65%-66%), moderate for EpiPen and Jext (29%-38%), and lowest for Emerade (13%-21%). Compression introduced a small intraosseous-injection risk with Emerade (4%). Female sex predicted subcutaneous injection (odds ratio, 1.3-2.0; all P < .001). Depending on the EAI, 29% to 97% of women and 0% to 41% of men would be injected subcutaneously. Older men were at risk of intraosseous Emerade injection. Obesity-related variables predicted subcutaneous injection poorly.

CONCLUSION

Anapen was associated with high subcutaneous-injection rates. EpiPen and Jext were projected to provide intramuscular injection in all men without risk of intraosseous injection. Emerade yielded the lowest subcutaneous-injection rates in women. Compression largely affected the muscle.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT02886468.

Anaphylaxis: A 2023 practice parameter update

This practice parameter update focuses on 7 areas in which there are new evidence and new recommendations. Diagnostic criteria for anaphylaxis have been revised, and patterns of anaphylaxis are defined. Measurement of serum tryptase is important for diagnosis of anaphylaxis and to identify underlying mast cell disorders. In infants and toddlers, age-specific symptoms may differ from older children and adults, patient age is not correlated with reaction severity, and anaphylaxis is unlikely to be the initial reaction to an allergen on first exposure. Different community settings for anaphylaxis require specific measures for prevention and treatment of anaphylaxis. Optimal prescribing and use of epinephrine autoinjector devices require specific counseling and training of patients and caregivers, including when and how to administer the epinephrine autoinjector and whether and when to call 911. If epinephrine is used promptly, immediate activation of emergency medical services may not be required if the patient experiences a prompt, complete, and durable response. For most medical indications, the risk of stopping or changing beta-blocker or angiotensin-converting enzyme inhibitor medication may exceed the risk of more severe anaphylaxis if the medication is continued, especially in patients with insect sting anaphylaxis. Evaluation for mastocytosis, including a bone marrow biopsy, should be considered for adult patients with severe insect sting anaphylaxis or recurrent idiopathic anaphylaxis. After perioperative anaphylaxis, repeat anesthesia may proceed in the context of shared decision-making and based on the history and results of diagnostic evaluation with skin tests or in vitro tests when available, and supervised challenge when necessary.

Epinephrine autoinjectors: individualizing device and dosage to optimize anaphylaxis management in the community setting

Background: Anaphylaxis is the most severe manifestation of a systemic allergic reaction, and, in the community setting, the immediate administration of an epinephrine autoinjector (EAI) can be life-saving. Physicians are tasked with selecting the most appropriate EAI for each individual and counseling patients and/or their caregivers to maximize the likelihood of successful deployment of the EAI. Objective: To offer an evidence-based expert clinical perspective on how physicians might best tailor EAI selection to their patients with anaphylaxis. Methods: A group of eight adult and pediatric allergists with expertise in anaphylaxis management reviewed and assessed the published data and guidelines on anaphylaxis management and EAI device selection. Results: Personalized EAI selection is influenced by intrinsic individual factors, extrinsic factors such as the properties of the individual EAI (e.g., dose, needle length, overall design) as well as cost and coverage. The number and the variety of EAIs available have expanded in most jurisdictions in recent years, which provide a greater diversity of options to meet the characteristics and needs of patients with anaphylaxis. Conclusion: There currently are no EAIs with customizable dose and needle length. Although precise personalization of each patient's EAI remains an optimistic future aspiration, careful consideration of all variables when prescribing EAIs can support optimal management of anaphylaxis.

CSACI position statement: transition recommendations on existing epinephrine autoinjectors

Epinephrine is the first line treatment for anaphylaxis, an acute potentially life-threatening allergic reaction. It is typically administered intramuscularly in the anterolateral thigh at a dose of 0.01 mg/kg of 1:1000 (1 mg/ml) solution to a maximum initial dose of 0.5 mg. Currently in Canada, epinephrine autoinjectors (EAI) are available in three doses, 0.15 mg, 0.30 mg, and 0.50 mg. There are currently no published studies comparing 0.3 mg and 0.5 mg EAIs in the paediatric or adult populations to compare clinical effectiveness. However, as weight increases above 30 kg, the percentage of the recommended 0.01 mg/kg epinephrine dose from an existing 0.3 mg EAI decreases resulting in potential underdosing. As such, The Canadian Society of Allergy and Immunology (CSACI) recommends that for those who weigh ≥ 45 kg, physicians could consider prescribing the 0.50 mg EAI based on shared decision making with patients.

Management of Anaphylaxis in Infants and Toddlers

Anaphylaxis is a systemic allergic reaction that can be caused by food, drugs, insect bites, or unknown triggers in infants and toddlers. Anaphylaxis rates are increasing. Infants and toddlers may have increased exposure to known and unknown allergens, decreased ability to describe their symptoms, and an expanded differential diagnosis for consideration on presentation. The most common symptoms in these age groups are cutaneous and gastrointestinal. Age-specific language may be helpful for caregivers to identify and describe the symptoms of anaphylaxis in infants and toddlers. Long-term management of anaphylaxis includes allergy evaluation to guide avoidance and assess prognosis and education on allergic reaction management; this incorporates the prescription of epinephrine autoinjector and provision of an allergy emergency plan.

Clinical Management of Infant Anaphylaxis

Anaphylaxis is a condition that is likely increasing in prevalence and commonly treated by allergists as well as other first responders and emergency room providers. Although a relatively rare event, anaphylaxis can occur in infants, with the most common cause attributed to foods. Infant anaphylaxis can present with unique diagnostic challenges and treatment considerations. While infants can present with classic signs and symptoms of anaphylaxis (eg, urticaria, angioedema, dyspnea, wheeze, and vomiting) they can also present with non-classical signs. Non-classical signs of infant anaphylaxis can include ear pulling, tongue thrusting, fussiness, and increase clinginess to the caregiver. These non-classic signs of infant anaphylaxis can often mimic normal infant behavior further complicating the diagnosis. Additionally, when treating infant anaphylaxis, there are special considerations regarding the use of epinephrine. These include determining appropriate needle length, dosages appropriate to administer depending on the weight of the infant, and the availability of different epinephrine auto-injectors. In this article, we aim to review the clinical management of infant anaphylaxis including diagnosis, recognition, treatment, strategies for follow-up and special considerations regarding epinephrine administration in this demographics.

Pharmacokinetic and pharmacodynamic evidence of adrenaline administered via auto-injector for anaphylactic reactions: A review of literature

Anaphylaxis is a severe allergic reaction that can lead to death if not treated quickly. Adrenaline (epinephrine) is the first-line treatment for anaphylaxis and its prompt administration is vital to reduce mortality. Following a number of high-profile cases, serious concerns have been raised, both about the optimal dose of intramuscular adrenaline via an auto-injector and the correct needle length to ensure maximal penetration every time. To date, the public data are sparse on the pharmacokinetics-pharmacodynamics of adrenaline administered via an auto-injector. The limited available literature showed a huge variation in the plasma concentrations of adrenaline administered through an auto-injector, as well as variations in the auto-injector needle length. Hence, delivering an effective dose during an anaphylaxis remains a challenge for both patients and healthcare professionals. Collaborative work between pharmacokinetics-pharmacodynamics experts, clinical triallists and licence holders is imperative to address this gap in evidence so that we can improve outcomes of anaphylaxis. In addition, we advise inclusion of expertise of human factors in usability studies given the necessity of carer or self-administration in the uniquely stressful nature of anaphylaxis.

Epinephrine auto-injector needle length: The impact of winter clothing

BACKGROUND

Epinephrine auto-injectors are expected to deliver the drug intramuscularly.

OBJECTIVE

To study whether injection through clothing influences the frequency of subcutaneous and intraosseous/periosteal deposition of epinephrine.

METHODS

Skin to muscle and skin to bone distances were measured for 303 children and adolescents and 99 adults. Distance was determined by ultrasound, with high or low pressure on the ultrasound probe. The risk/percentage of subcutaneous and intraosseous/periosteal injections was calculated using the lower and upper limits for the authority-approved length of EAI needles as provided by two high pressure EAI manufacturers and one low pressure EAI manufacturer. The addition winter clothing on the delivery of epinephrine was illustrated by comparing drug delivery fissue depth with no clothes. Furthermore, the riof non-intramuscular delivery for the shortest and longest approved needle length was calculated.

RESULTS

When using EpipenJr® in children < 15 kg the risk of intraosseous/periostal injection was reduced from 1% and 59% for the shortest and longest approved needle length to 0 and 15% with winter clothes. The Auvi-Q® 0.1 mg had no risk of intraosseous/periosteal injection. However, the subcutaneous deposition risk increased from 94% and 28% to 100% and 99% with winter clothes. The risk of subcutaneous injection using EpipenJr® in the youngest children increased from 13% and 0% to 81% and 1% with winter clothes, and with Epipen® in adults from 45% and 17% to 60% and 38%. Emerade®, had a risk of subcutaneous injection in adults increasing from 14% and 10% to 28% and 21% adding winter clothes.

CONCLUSION

The risk of intraosseous/periosteal injections decreases and the risk of subcutaneous injection increases when injecting through winter clothes for all EAIs.

Infant anaphylaxis: Diagnostic and treatment challenges

Immediate administration of intramuscular epinephrine to a patient experiencing anaphylaxis is the first-line therapy for this life-threatening allergic reaction. Alhough anaphylaxis is generally a rare occurrence, it has dire consequences if left untreated. In infants, anaphylaxis is typically triggered by exposure to egg, cow's milk, or peanuts. The rapid onset of symptoms in multiple organ systems makes an accurate diagnosis in infants difficult because there are numerous ways in which anaphylaxis may present. The symptoms of infant anaphylaxis are often underrecognized or misdiagnosed for less serious illnesses or even normal findings, including drooling, loose stools, and irritability. Because infants are mostly nonverbal-and most pediatric emergency department visits for anaphylaxis cases are the first diagnosis-ascertaining potential exposure to common allergens is difficult; this further complicates diagnosis in these youngest patients for whom the clinical presentation of anaphylaxis varies widely. A key factor in diagnosing anaphylaxis is the temporal profile of symptom development following allergen exposure; however, some children with anaphylaxis develop symptoms that reoccur hours or days after an initial anaphylactic reaction, making diagnosis challenging. Advanced practice nurses are often the first health care provider to encounter a patient who may be experiencing anaphylaxis. Although diagnostic criteria exist for anaphylaxis, specific criteria for the diagnosis of anaphylaxis in infants have not been developed. As such, it is important to understand and recognize the variable presentation of anaphylaxis in infants and to rapidly diagnose and treat with epinephrine.

Food-induced anaphylaxis in infancy compared to preschool age: A retrospective analysis

OBJECTIVE

Little is known regarding food anaphylaxis in infancy. We aimed to describe specificities of food anaphylaxis in infants (≤12 months) as compared to preschool children (1-6 years).

METHODS

We conducted a retrospective study of all food anaphylaxis cases recorded by the Allergy Vigilance Network from 2002 to 2018, in preschool children focusing on infants.

RESULTS

Of 1951 food anaphylaxis reactions, 61 (3%) occurred in infants and 386 (20%) in preschool children. Two infants had two anaphylaxis reactions; thus, we analyzed data among 59 infants (male: 51%; mean age: 6 months [SD: 2.9]); 31% had a history of atopic dermatitis, 11% of previous food allergy. The main food allergens were cow's milk (59%), hen's egg (20%), wheat (7%) and peanut (3%) in infants as compared with peanut (27%) and cashew (23%) in preschool children. Anaphylaxis occurred in 28/61 (46%) cases at the first cow's milk intake after breastfeeding discontinuation. Clinical manifestations were mainly mucocutaneous (79%), gastrointestinal (49%), respiratory (48%) and cardiovascular (21%); 25% of infants received adrenaline. Hives, hypotension and neurologic symptoms were more likely to be reported in infants than in preschool children (P = .02; P = .004; P = .002, respectively). Antihistamines and corticosteroids were more often prescribed in preschool children than in infants (P = .005; P = .025, respectively).

CONCLUSION

Our study found that in infants presenting with their first food allergy, in a setting with a high rate of infant formula use, the most predominant trigger was cow's milk. As compared to older preschool children, hives, hypotonia and hypotension were more likely to be reported in infants. We believe that this represents a distinct food anaphylaxis phenotype that can further support developing the clinical anaphylaxis criteria in infants.

Implications of variation of epinephrine auto-injector needle length

BACKGROUND

The variation of needle lengths of epinephrine auto-injectors (EAIs) has not been investigated.

OBJECTIVE

To investigate the impact of the variation of the needle length of EAIs.

METHODS

Skin-to-muscle (STMD) and skin-to-bone distances (STBD) were measured for 303 children and adolescents and 99 adults. Distance was determined by ultrasound, applying high or low pressure on the probe. The risk of subcutaneous and periosteal/intraosseous injection was calculated using the lower and upper acceptance limits for length of EAI needles as provided for 3 high-pressure EAIs (HPEAI) and 1 low-pressure EAI (LPEAI).

RESULTS

The variation in needle length of the HPEAIs are for Epipen Jr/Epipen 5 mm, for Jext 2 mm, for Auvi-Q 2.5 mm, and for the LPEAI, Emerade, 1.5 mm. When using the longest acceptable needles for Epipen Jr, the risk of intraosseous/periosteal penetration was highest in children weighing less than 15 kg at 60% and for Jext at 43%. The risk was low for Auvi-Q and Emerade. The risk of subcutaneous injection was greatest with the shortest needles of the Auvi-Q 0.1 mg at 94% in children weighing less than 15 kg. In adults, the risk of subcutaneous injection using the shortest needles was for Epi-Pen at 41%, Jext at 36%, Auvi-Q at 38%, and Emerade at 12%.

CONCLUSION

The variation in needle length of EAIs influences the risk of subcutaneous and intraosseous/periosteal injections. Compared with Epipen Jr, the Auvi-Q 0.1 mg for children weighing less than 15 kg had a low risk of intraosseous/periosteal injection but a very high risk of subcutaneous injection. For adults, there is a significant risk of subcutaneous injection.

Point-of-care ultrasonography in the allergy and immunology clinic

OBJECTIVE

To summarize evidence supporting the use of point-of-care ultrasonography as a clinical tool for allergists and immunologists.

DATA SOURCES

Cochrane Library, Medline, EMBASE, and Scopus databases were searched for articles published before December 18, 2018.

STUDY SELECTIONS

We included any retrospective or prospective study that evaluated ultrasonography in allergy and immunology and epinephrine autoinjector (EAI) needle length.

RESULTS

The standard EAI needle length may be inadequate for intramuscular delivery of epinephrine, particularly for women, at risk of anaphylaxis. In patients who weigh less than 15 kg, the lengths of commercially available EAIs may be too long, risking inadvertent intraosseous injection and resultant complications. Ultrasonography can be routinely used in the allergy clinic to guide needle length and angle for subcutaneous allergen immunotherapy injections to minimize systemic adverse effects.

CONCLUSION

Point-of-care ultrasonography can be a useful tool to enhance patient care and safety in an allergy clinic. Ideally, all patients prescribed EAIs should have ultrasonographic measurement of the skin to muscle distance and skin to bone distance to assist in identifying patients at risk of subcutaneous or intraosseous injection in anaphylaxis and those at risk of intramuscular injection during subcutaneous allergen immunotherapy injections.

Guiding Principles for the Recognition, Diagnosis, and Management of Infants with Anaphylaxis: An Expert Panel Consensus

Infant anaphylaxis is an emerging risk, with food allergy the most common cause. Although the presentation of anaphylaxis involves the same systems as in older children and adults, there are real-world challenges to identifying symptoms of an allergic emergency in nonverbal children, as well as implementing optimal treatment. Recognition of anaphylaxis in infants can be challenging because allergic symptoms and certain normal infant behaviors may overlap. Intramuscular epinephrine is the treatment of choice for infants, as it is for older children and adults, and an epinephrine autoinjector approved by the Food and Drug Administration is now available for infants weighing between 7.5 and 15 kg. A panel of experts sought to develop guiding principles for the recognition, diagnosis, and management of anaphylaxis in infants, and provide a framework for the development of new guidelines and future research. Accordingly, anaphylaxis emergency action planning for infants was addressed by the panel. In considering formation of future infant anaphylaxis guidelines, health care providers should be aware of the needs to improve the recognition, diagnosis, and management of infants with anaphylaxis. Future research should identify and validate clinical criteria for the diagnosis of anaphylaxis in infants, as well as risk factors for the most severe reactions.

Unintentional injection to the bone with a pediatric epinephrine auto-injector

Background

Skin-to-bone distance (STBD) in children prescribed a pediatric epinephrine auto-injector (EAI) for anaphylaxis is not commonly measured in practice. Recent evidence suggests that children with STBD less than the exposed needle length of available pediatric EAIs (dose: 0.15 mg, needle length: 12.7 mm) are at risk for unintentional injections to the bone during their use for an allergic emergency.

Case presentation

Described here is a case of a female child with multiple food allergies prescribed a pediatric EAI (0.15 mg EpiPen Jr^®) who experienced an unintentional injection to her femur. The patient’s STBD at the recommended injection site (vastus lateralis) was shorter than the needle length of her prescribed EAI (12.7 mm) at the time of the injury (age: 7, height: 122 cm; weight: 25 kg), even though her weight was within the indication for this EAI (15–30 kg). The patient and her family were made aware of the risk of unintentional bone injection at the time the EAI was prescribed.

Conclusions

Some children, even those at an appropriate weight per the indication of available pediatric EAIs (0.15 mg), may be at risk for unintentional injections to the bone. The effects of an unintentional bone injection with an EAI can have lasting effects on a child, including pain. Healthcare providers who prescribe pediatric EAIs for any child should consider evaluating this risk, inform patients and parents of the risk, and take measures to potentially mitigate unintentional bone injections. For some children, an EAI with a shorter needle length may be a more appropriate choice of treatment for anaphylaxis.

Epinephrine, auto-injectors, and anaphylaxis: Challenges of dose, depth, and device

OBJECTIVE

This review was undertaken to review epinephrine dosing, site and route of administration, focusing on special populations (patients weighing less than 15 kg, and obese patients); and to discuss storage and delivery of epinephrine in prehospital and hospital settings.

DATA SOURCES

Review of published literature.

STUDY SELECTION

Relevance.

RESULTS

The recommended 0.01-mg/kg (maximum 0.3-0.5 mg) epinephrine dose in anaphylaxis is based on limited pharmacokinetic data in healthy volunteers. No pharmacokinetic or pharmacodynamics studies involving patients in anaphylaxis have been published. When epinephrine auto-injectors (EAIs) are used in infants, the dose increasingly exceeds the recommended dose as weight decreases, although the clinical significance of this is unclear. Limited data indicate that the intramuscular route and lateral thigh site are superior. Ultrasound studies suggest that 0.15 EAI needles may be too long for many patients weighing less than 15 kg, and 0.3 mg EAI needles may be too short for obese patients weighing more than 30 kg. A newly available 0.1 mg EAI has a lower dose and shorter needle better suited to patients weighing 7.5 to 15 kg. In some medical settings, vials and syringes may provide a safe, efficient alternative with substantial cost savings over EAIs.

CONCLUSION

EAIs should be available in the community with doses and needle depths that meet the needs of all patients. More research on epinephrine pharmacodynamics are needed in children and adults in anaphylaxis, to better delineate what optimal doses should be. Optimizing epinephrine dose and delivery has the potential to improve anaphylaxis outcomes and prevent adverse events.

Epinephrine auto-injector needle lengths: Can both subcutaneous and periosteal/intraosseous injection be avoided?

BACKGROUND

Epinephrine should be administered intramuscularly in the anterolateral aspect of the thigh. The length of the epinephrine auto-injector (EAI) needle should ensure intramuscular injection.

OBJECTIVE

To discuss suitable EAI needle lengths based on ultrasound measurements related to weight.

METHODS

The skin-to-muscle distance (STMD) and skin-to-bone distance (STBD) were measured by ultrasound in the mid-third of the anterolateral area of the right thigh when applying high pressure (8 lb; high-pressure EAI [HPEAI]) or low pressure (low-pressure EAI [LPEAI]) on the ultrasound probe. The study included 302 children and adolescents and 99 adults. The maximum and minimum STMD and the maximum and minimum STBD were estimated.

RESULTS

Using HPEAIs, the risk of periosteal or intraosseous penetration was 32% in children weighing less than 15 kg. The risk of subcutaneous injection was 12% in adolescents and 33% in adults. With LPEAIs, there was no risk of periosteal or intraosseous injection and the risk of subcutaneous injections in adolescents and adults was lower at 2% and 10%, respectively. A new EAI for injection in small children would have no risk of periosteal or intraosseous injection but would have 71% chance of subcutaneous deposit of epinephrine.

CONCLUSION

Common HPEAIs have a high risk of periosteal or intraosseous penetration in children and subcutaneous injections in overweight and obese adults. LPEAIs have some risk of subcutaneous injection in adults. HPEAIs with 0.1 mg of epinephrine and shorter needles have no risk of periosteal or intraosseous injection but have a high risk of subcutaneous deposit. For adult or overweight or obese patients, HPEAIs and LPEAIs should have longer needles. Future studies should focus on triggering pressures and variations in needle length.

Bioavailability and Cardiovascular Effects of Adrenaline Administered by Anapen Autoinjector in Healthy Volunteers

BACKGROUND

The administration of adrenaline is a life-saving intervention for anaphylactic reactions. However, it has been questioned whether the needle length of the autoinjectors is sufficient to achieve genuine intramuscular delivery and optimal bioavailability.

OBJECTIVE

To assess the adequacy of Anapen, which has a relatively short needle length (10.5 mm), through a comparison of the depot localization, plasma pharmacokinetics, and cardiovascular responses of adrenaline delivered via Anapen versus a prefilled syringe with a 25.4-mm needle, which is generally used for intramuscular injections.

METHODS

This randomized, open-label, crossover study compared the impact of adrenaline administration at 2 sites in the thigh of 18 normal weight male volunteers, using either Anapen or the prefilled syringe; in addition, we studied the treatment of 12 overweight women with Anapen. The depot depth was measured by ultrasonography, plasma adrenaline level was evaluated by ultra performance liquid chromatography-mass spectrometry (UPLC-MS), and heart rates were measured using a Holter monitor.

RESULTS

Intramuscular injections were given with both devices at both thigh sites in nonobese men, but not in overweight women. Adrenaline levels showed a double peak, with parallel changes in the heart rate. The first peak, of potential vital importance in anaphylaxis treatment, occurred at approximately 10 minutes postinjection, with maximum concentration and area under the curve significantly higher with Anapen than with prefilled syringes; the magnitude of the second peak did not differ among the various conditions. Unexpectedly, in overweight women treated with Anapen, the magnitude of the first peak was similar to that observed in men, despite the injection being subcutaneous, and the overall bioavailability was enhanced.

CONCLUSIONS

Needle length and intramuscular injection are not absolute requirements for autoinjector efficacy, but the monitoring of injection location, biphasic adrenaline levels, and cardiovascular responses is important for the assessment of their therapeutic relevance in anaphylaxis.

Contemporary issues in anaphylaxis and the evolution of epinephrine autoinjectors: What will the future bring?

BACKGROUND

Food allergy and anaphylaxis appear to be increasing in the United States, especially in young children, and preparedness is paramount to successful emergency management in the community. Although the treatment of choice for anaphylaxis is epinephrine delivered by autoinjection, some devices are challenged by less user-friendly designs or pose the risk of injury, especially in young patients. Human factors engineering has played a larger role in the development of more recent epinephrine autoinjector technologies and will continue to play a role in the evolution and future design of epinephrine autoinjectors.

OBJECTIVE

To discuss contemporary issues related to the identification and management of anaphylaxis, current and future epinephrine autoinjector design, and unmet needs for the treatment of special populations, namely, young children weighing less than 15 kg.

METHODS

The literature was reviewed and select articles retrieved to support expert clinical opinions on the need for improved recognition of anaphylaxis, epinephrine autoinjector design, and unmet needs in special populations.

RESULTS

Anaphylaxis may be underrecognized and poorly defined in infant- and toddler-aged children, current devices may not be adequate to safely treat these patients (ie, inappropriate needle length), and health care professionals may not be aware of these issues.

CONCLUSION

As epinephrine autoinjector technology continues to evolve, device characteristics that promote safe, user-friendly experiences and give clinicians and their patients confidence to successfully treat anaphylaxis during an emergency, without injury, will be favored.