Poison Ivy, Oak, and Sumac Dermatitis: What Is Known and What Is New?

New insight in secretory structures and secretion composition in Rhus typhina L. - Anatomical, histochemical, and ultrastructural studies

Rhus typhina is a valuable plant used in the pharmaceutical, cosmetic, and food industries due to the presence of biologically active substances accumulated in its organs, especially in secretory structures, i.e. trichomes and secretory ducts. Light microscopy, scanning electron microscopy, and transmission electron microscopy were used to examine the structure of glandular and non-glandular trichomes, as well as secretory ducts present in inflorescence peduncles of R. typhina. The chemical composition of the secretion produced by trichomes and ducts was assessed using histochemical techniques, including observations under brightfield and fluorescence microscopes. Two types of capitate glandular trichomes producing secretions with a similar composition and non-glandular trichomes exhibiting secretory activity were identified. The secretion of glandular trichomes was dominated by acidic and neutral lipids, essential oil, sesquiterpenes, and steroid-containing terpenes. The schizogenic secretory ducts located in the phloem produced a viscous milky substance with acidic polysaccharides, acidic lipids, phenolic compounds, and proteins. The secretion was released into the duct lumen through notches in the walls of the secretory epithelial cell facing the duct lumen. The location, type, and traits of the non-glandular trichomes and secretory structures, as well as the composition of the secreted products are considered important taxonomic features in the family Anacardiaceae and the Rhus genus. Additionally, these characters are important diagnostic markers for the pharmacobotanical identification of the species in medicinal and cosmetic raw materials. The various compounds present in the secretory structures of R. typhina may contribute to plant protection against pathogens or herbivory and probably play a role as attractants for pollinators and seed dispersers.

Innovation in prevention of poison oak contact dermatitis

Poison oak-induced contact dermatitis poses a significant challenge due to its urushiol oil-induced allergic reactions. Conventional preventive measures like avoidance and post-exposure cleansing are often impractical, necessitating innovative strategies. This comprehensive review explores emerging technologies and formulations for preventing poison oak dermatitis. Literature search via PubMed and Covidence identified 13 relevant studies, with six discussing preventive measures. Barrier methods, including occlusive creams and protective clothing, showed promise in reducing dermatitis risk. Immunotherapy, although investigated, requires further development. Complete avoidance, while effective, is often impractical. The complexity of poison oak management underscores the need for ongoing research to develop more effective preventive measures. This review highlights the current landscape, identifies gaps in knowledge, and emphasizes the importance of continued research for improved prevention and management of poison oak-induced dermatitis.

Aloe-emodin relieves allergic contact dermatitis pruritus by inhibiting mast cell degranulation

Urushiol-induced allergic contact dermatitis (ACD) is a chronic inflammatory skin disease in which skin barrier dysfunction leads to pruritus and eczematous lesions. ACD is triggered by immune imbalance. Aloe emodin is an anthraquinone derivative extracted from rhubarb, aloe and other traditional Chinese medicines. It has a wide range of pharmacological effects, including anti-inflammatory, anti-tumor, and anti-allergic effects. The purpose of our study was to demonstrate the effectiveness of aloe-emodin on urushiol-induced acute pruritus and allergic contact dermatitis. The results showed that urushiol could stimulate keratinocytes to release chemokines CXCL1, CXCL2, CCL2, TSLP, and TNF-α, which recruit or activate mast cells. Aloe-emodin treatment inhibited inflammatory-response-induced mast cell degranulation in skin lesions and suppressed the expression of inflammatory cytokines, such as interleukin-4, and interleukin-6. Therefore, the results indicate that aloe-emodin can improve urushiol-induced acute pruritus and allergic contact dermatitis in mice by inhibiting mast cell degranulation.

Plant Dermatitis

Plant dermatitis is a common pathology that plagues those who work and recreate in the North American outdoors. The most common plant family to cause dermatitis is the Toxicodendron genus, which includes the plants known by the common names of poison ivy, poison oak, and poison sumac. While mortality is usually quite low for this pathology, the incidence and prevalence of the disease leads to substantial healthcare burden and financial implications across the population. The mainstays of treatment have focused on prevention, corticosteroids, and antihistamines.

Role of Innate Immunity in Allergic Contact Dermatitis: An Update

Our understanding of allergic contact dermatitis mechanisms has progressed over the past decade. Innate immune cells that are involved in the pathogenesis of allergic contact dermatitis include Langerhans cells, dermal dendritic cells, macrophages, mast cells, innate lymphoid cells (ILCs), neutrophils, eosinophils, and basophils. ILCs can be subcategorized as group 1 (natural killer cells; ILC1) in association with Th1, group 2 (ILC2) in association with Th2, and group 3 (lymphoid tissue-inducer cells; ILC3) in association with Th17. Pattern recognition receptors (PRRs) including toll-like receptors (TLRs) and nucleotide-binding oligomerization domain (NOD)-like receptors (NLRs) in innate immune cells recognize damage-associated molecular patterns (DAMPs) and cascade the signal to produce several cytokines and chemokines including tumor necrosis factor (TNF)-α, interferon (IFN)-α, IFN-γ, interleukin (IL)-1β, IL-4, IL-6, IL-12, IL-13, IL-17, IL-18, and IL-23. Here we discuss the recent findings showing the roles of the innate immune system in allergic contact dermatitis during the sensitization and elicitation phases.

Investigation into Propolis Components Responsible for Inducing Skin Allergy: Air Oxidation of Caffeic Acid and Its Esters Contribute to Hapten Formation

Propolis is a resin-like material produced by bees from the buds of poplar and cone-bearing trees and is used in beehive construction. Propolis is a common additive in various biocosmetics and health-related products, despite the fact that it is a well-known cause of contact allergy. Caffeic acid and its esters have been the primary suspects behind the sensitization potency of propolis-induced contact allergy. However, the chemical structures of the protein adducts formed between these haptens and skin proteins during the process of skin sensitization remain unknown. In this study, the reactivity of three main contact allergens found in propolis, namely, caffeic acid (CA), caffeic acid 1,1-dimethylallyl ester (CAAE), and caffeic acid phenethyl ester (CAPE), was investigated. These compounds were initially subjected to the kinetic direct peptide reactivity assay to categorize the sensitization potency of CA, CAAE, and CAPE, but the data obtained was deemed too unreliable to confidently classify their skin sensitization potential based on this assay alone. To further investigate the chemistry involved in generating possible skin allergy-inducing protein adducts, model peptide reactions with CA, CAAE, and CAPE were conducted and analyzed via liquid chromatography-high-resolution mass spectrometry. Reactions between CA, CAAE, and CAPE and a cysteine-containing peptide in the presence of oxygen, both in closed and open systems, were monitored at specific time points. These studies revealed the formation of two different adducts, one corresponding to thiol addition to the α,β-unsaturated carbonyl region of the caffeic structure and the second corresponding to thiol addition to the catechol, after air oxidation to o-quinone. Observation of these peptide adducts classifies these compounds as prehaptens. Interestingly, no adduct formation was observed when the same reactions were performed under oxygen-free conditions, highlighting the importance of air oxidation processes in CA, CAAE, and CAPE adduct formation. Additionally, through NMR analysis, we found that thiol addition occurs at the C-2 position in the aromatic ring of the CA derivatives. Our results emphasize the importance of air oxidation in the sensitization potency of propolis and shed light on the chemical structures of the resultant haptens which could trigger allergic reactions in vivo.

Chemical and cytotoxicity profiles of 11 pink pepper (Schinus spp.) samples via non-targeted hyphenated high-performance thin-layer chromatography

INTRODUCTION

Pink pepper is a worldwide used spice that corresponds to the berries of two species, Schinus terebinthifolia Raddi or S. molle L. (Anacardiaceae). Toxic and allergic reactions by ingestion or contact with these plants were reported, and classical in vitro studies have highlighted the cytotoxic properties of apolar extracts from the fruits.

OBJECTIVES

Perform a non-targeted screening of 11 pink pepper samples for the detection and identification of individual cytotoxic substances.

METHODS

After reversed-phase high-performance thin-layer chromatography (RP-HPTLC) separation of the extracts and multi-imaging (UV/Vis/FLD), cytotoxic compounds were detected by bioluminescence reduction from luciferase reporter cells (HEK 293 T-CMV-ELuc) applied directly on the adsorbent surface, followed by elution of detected cytotoxic substance into atmospheric-pressure chemical ionization high-resolution mass spectrometry (APCI-HRMS).

RESULTS

Separations for mid-polar and non-polar fruit extracts demonstrated the selectivity of the method to different substance classes. One cytotoxic substance zone was tentatively assigned as moronic acid, a pentacyclic triterpenoid acid.

CONCLUSION

The developed non-targeted hyphenated RP-HPTLC-UV/Vis/FLD-bioluminescent cytotoxicity bioassay-FIA-APCI-HRMS method was successfully demonstrated for cytotoxicity screening (bioprofiling) and respective cytotoxin assignment.

Chemical- and Drug-Induced Allergic, Inflammatory, and Autoimmune Diseases Via Haptenation

Haptens are small molecules that only elicit an immune response when bound to proteins. Haptens initially bind to self-proteins and activate innate immune responses by complex mechanisms via inflammatory cytokines and damage-associated molecular patterns and the subsequent upregulation of costimulatory signals such as cluster of differentiation 86 (CD86) on dendritic cells. Subsequent interactions between CD86 and CD28 on T cells are critically important for properly activating naive T cells and inducing interleukin 2 production, leading to the establishment of adaptive immunity via effector and memory T cells. Accumulating evidence revealed the involvement of haptens in the development of various autoimmune-like diseases such as allergic, inflammatory, and autoimmune diseases including allergic contact dermatitis, atopy, asthma, food allergy, inflammatory bowel diseases, hemolytic anemia, liver injury, leukoderma, and even antitumor immunity. Therefore, the development of in vitro testing alternatives to evaluate in advance whether a substance might lead to the development of these diseases is highly desirable. This review summarizes and discusses recent advances in chemical- and drug-induced allergic, inflammatory, and autoimmune diseases via haptenation and the possible molecular underlying mechanisms, as well as in vitro testing alternatives to evaluate in advance whether a substance might cause the development of these diseases.

Notulae to the Italian alien vascular flora: 14

In this contribution, new data concerning the distribution of vascular flora alien to Italy are presented. It includes new records, confirmations, and status changes for Italy or for Italian administrative regions. Nomenclatural and distribution updates, published elsewhere, and corrections are provided as Suppl. material 1.

Community-associated Methicillin-Resistant Staphylococcus aureus (ca-MRSA) as a Pandemic Pathogen: Risk Factors and Implications for Healthcare

Background A diversity of risk factors for ca-MRSA manifestations has been described so far. Up to date toxic contact dermatitis induced by plants has not been identified as one.

Patients and Methods After intense skin contact with poison ivy in the US a 24-year-old Afro-American showed pronounced bullous contact dermatitis on the back of the neck and subsequently massive ca-MRSA furunculitis with proof of Panton-Valentin-leukocidin (PVL). After travelling to Germany, his German girlfriend developed a subacute ca-MRSA, PVL-positive superinfection of a mosquito bite at her lower leg. Both infections required surgical intervention.

Results While the male patient displayed contact dermatitis by poison ivy, the female patient demonstrated two risk factors for ca-MRSA: contact with a ca-MRSA positive person and a predisposing skin lesion. Both cases underpin the role of ca-MRSA transmission and the potential severeness of wound infections in young and immunocompetent persons, just to be resolved by invasive intervention.

Conclusions Marked and recalcitrant skin or soft tissue infections in otherwise healthy young patients require instant microbiological analysis and surgical intervention flanked by adequate antibiotic therapy. Contact dermatitis induced by plant toxins should be taken into consideration as possible risk factor for the acquisition of ca-MRSA.

Black-Spot Toxicodendron Dermatitis With Varied Presentation

This article describes the clinical presentation, differential diagnosis, and treatment of 2 unrelated cases with different presentations of black-spot Toxicodendron dermatitis. In the first case, a healthy 7-y-old male presented with a rash consisting of black dots with localized surrounding erythema on the left arm. The rash then progressed to a vesicular, pinpoint, raised rash spreading to the face, arms, and neck. In the second case, a 4-y-old male presented with non-pruritic, black, flat, non-erythematous lesions that did not progress. This patient's older sibling had been diagnosed with poison ivy 1 wk prior, and they attended the same child care where the poison ivy was thought to be acquired. In both cases, diagnosis of black-spot Toxicodendron dermatitis was made. The black spot of Toxicodendron dermatitis is caused by urushiol oxidation on exposure to air. The subject may or may not go on to develop allergic contact dermatitis after the exposure. Diagnosis of this dermatitis is made on clinical presentation, with careful consideration of history, distribution, and lesion morphology. When allergic dermatitis does develop as in the first case, systemic treatment with oral steroids is recommended. In both of these cases the black dots completely resolved in 2 to 3 wk. Dermatologic referral for dermoscopy and biopsy may be necessary if the dermatosis does not resolve as anticipated.

Establishing Consensus on the Treatment of Toxicodendron Dermatitis

BACKGROUND

Toxicodendron dermatitis (TD) is a common form of allergic contact dermatitis that affects millions of Americans every year. Studies have shown that although there are general recommendations for the treatment of TD, there are no treatment algorithms for clinicians to follow when patients present with TD.

OBJECTIVE

The objective of this study was to achieve consensus on the treatment of TD to create practical guidelines for physicians who treat TD.

METHODS

Data were collected from March 2020 to April 2021. This study included semistructured focus groups and a Delphi Study with dermatologists to achieve consensus.

RESULTS

A total of 51 dermatologists were included in the Delphi. Final agreement with proposed severity criteria ranged from 90.9% to 100.0%. Primary indicators of disease severity were body surface area, presence and severity of pruritus, and anatomic locations of eruptions with 77.4% agreement. Final agreement for the treatment algorithm was over the threshold majority agreement at 67.6%.

CONCLUSIONS

Literature guiding the treatment of TD is scarce. The use of the Delphi method and focus groups can help expand dermatological resources both within dermatology and to other specialties that may need to treat skin conditions.

Itchy Toxicodendron Plant Dermatitis

Plants such as the Toxicodendron species, consisting of poison ivy, poison oak, and poison sumac, largely contribute to allergic contact dermatitis with itch as a predominate symptom. Many individuals are affected by this skin condition, with approximately 50% to 70% of adults in North America demonstrating a degree of clinical sensitivity to this species of plants. In this review, we discuss the prevalence, pathophysiology, and clinical features of this contact dermatitis, as well as both treatment and prevention directed towards alleviation of itch. Updated research is emphasized throughout this review, although it is evident that this field is evolving, and more research is necessary to enhance treatment.

The Association Between Allergic Contact Dermatitis and Erythema Multiforme: A Systematic Review of the Literature

ABSTRACT

The relationship between erythema multiforme (EM) and allergic contact dermatitis (ACD) remains unclear. There have been multiple reports of EM-like lesions occurring in conjunction with or presenting after ACD; however, various definitions and terminologies have been used to denote the patient's diagnosis in these cases. In this systematic review, we summarize the key presenting features of recent cases of EM-like eruptions associated with ACD, as well as diagnostic findings, responsible allergens, treatments, and outcomes. We propose that, whenever possible, these cases should be classified into 2 distinct categories: (1) EM-like ACD and (2) EM after ACD (ACD-induced EM). Because the clinical courses, potential complications, and treatment plans differ between the two, a critical need exists for further characterization and distinguishment of EM-like ACD and ACD-induced EM.

Medical Care at California Wildfire Incident Base Camps

OBJECTIVE

The California Emergency Medical Services Authority manages and deploys California Medical Assistance Teams (CAL-MAT) to disaster medical incidents in the state. This analysis reviews diagnoses for ambulatory medical visits at multiple wildland fire incident base camp field sites in California during the 2020 fire season.

METHODS

Clinical data without personal health information were extracted retrospectively from patient care records from all patients seen by a provider. Results were entered into Excel spreadsheets with calculation of summary statistics.

RESULTS

During the 2020 fire season, CAL-MAT teams deployed 21 times for a total of 327 days to base camps supporting large fire incidents and cared for 1756 patients. Impacts of heat and environmental smoke are a constant factor near wildfires; however, our most common medical problem was rhus dermatitis (54.5%) due to poison oak. All 2020 medical missions were further complicated by prevention and management of coronavirus disease (COVID-19).

CONCLUSIONS

There is very little literature regarding the acute medical needs facing responders fighting wildland fires. Ninety-five percent of clinical conditions presenting to a field medical team at the wildfire incident base camp during a severe fire season in California can be managed by small teams operating in field tents.

Time Trends in Patient Characteristics and In-Hospital Adverse Events for Primary Total Knee Arthroplasty in the United States: 2010-2017

Background

Perioperative care for total knee arthroplasty (TKA) has improved over time. We present an analysis of inpatient safety after TKA.

Methods

14,057 primary TKAs captured by the Medicare Patient Safety Monitoring System between 2010 and 2017 were retrospectively reviewed. We calculated changes in demographics, comorbidities, and adverse events (AEs) over time. Risk factors for AEs were also assessed.

Results

Between 2010 and 2017, there was an increased prevalence of obesity (35.1% to 57.6%), tobacco smoking (12.5% to 17.8%), and renal disease (5.2% to 8.9%). There were reductions in coronary artery disease (17.3% to 13.4%) and chronic warfarin use (6.7% to 3.1%). Inpatient AEs decreased from 4.9% to 2.5%, (P < .01), primarily driven by reductions in anticoagulant-associated AEs, including major bleeding and hematomas (from 2.8% to 1.0%, P < .001), catheter-associated urinary tract infections (1.1% to 0.2%, P < .001), pressure ulcers (0.8% to 0.2%, P < .001), and venous thromboembolism (0.3% to 0.1%, P = .04). The adjusted annual decline in the risk of developing any in-hospital AE was 14% (95% confidence interval [CI] 10%-17%). Factors associated with developing an AE were advanced age (odds ratio [OR] = 1.01, 95% CI 1.00-1.01), male sex (OR = 1.21, 95% CI 1.02-1.44), coronary artery disease (OR = 1.35, 95% CI 1.07-1.70), heart failure (OR = 1.70, 95% CI 1.20-2.41), and renal disease (OR = 1.71, 95% CI 1.23-2.37).

Conclusions

Despite increasing prevalence of obesity, tobacco smoking, and renal disease, inpatient AEs after primary TKA have decreased over the past several years. This improvement is despite the increasing complexity of the inpatient TKA population over time.

Environmental Causes of Dermatitis

Environmental, or exogenous, dermatitis is comprised of irritant and allergic contact dermatitis, which account for 80% and 20% of cases of contact dermatitis, respectively. Contact dermatitis is extremely common, and failure to diagnose this entity may result in overlooking a potentially curable driver of disease. In this review, we describe how clinical features, such as morphology or history, can assist in distinguishing exogenous from endogenous causes of dermatitis, and allergic from irritant contact dermatitis. Additionally, we provide an overview of common contact allergens and how dermatitis distribution can suggest possible culprit allergens. Patch testing is needed to confirm contact allergy.

Roles of Lipids in the Permeability Barriers of Skin and Oral Mucosa

PubMed searches reveal much literature regarding lipids in barrier function of skin and less literature on lipids in barrier function of the oral mucosa. In terrestrial mammals, birds, and reptiles, the skin’s permeability barrier is provided by ceramides, fatty acids, and cholesterol in the outermost layers of the epidermis, the stratum corneum. This layer consists of about 10–20 layers of cornified cells embedded in a lipid matrix. It effectively prevents loss of water and electrolytes from the underlying tissue, and it limits the penetration of potentially harmful substances from the environment. In the oral cavity, the regions of the gingiva and hard palate are covered by keratinized epithelia that much resemble the epidermis. The oral stratum corneum contains a lipid mixture similar to that in the epidermal stratum corneum but in lower amounts and is accordingly more permeable. The superficial regions of the nonkeratinized oral epithelia also provide a permeability barrier. These epithelial regions do contain ceramides, cholesterol, and free fatty acids, which may underlie barrier function. The oral epithelial permeability barriers primarily protect the underlying tissue by preventing the penetration of potentially toxic substances, including microbial products. Transdermal drug delivery, buccal absorption, and lipid-related disease are discussed.

Occupational Contact Dermatitis: An Update

Occupation contact dermatitis (CD) is a common inflammatory skin condition impacting every professional industry in the United States. It is associated with significant personal and professional distress, loss of revenue, and decreased productivity. Occupational CD is further subdivided into irritant CD and allergic CD. Frequently, workers may suffer from a combination of both types. Numerous workplace exposures are implicated, but there are several themes across professions, such as CD related to frequent handwashing and wet work. A detailed occupational history, physical examination, and patch testing can help to make the diagnosis. Treatment includes identification of the substance and avoidance, which often is quite challenging.

Comparative Study on Different Skin Pruritus Mouse Models

The animal model is an important tool to study the mechanism of disease formation. Different animal models of pruritus have been adopted based on the purpose of researchers in the study of the itching mechanism. Although the symptoms of various models are quite different, scratching behavior is a key indicator. Therefore, it is necessary to find an animal model that can quickly induce animal scratching and maintain the stability of scratching behavior. In this study, we compared animal models of pruritus induced by four substances and found that the scratching behavior of mice induced by urushiol not only reached the plateau stage quickly but also showed more stability in the plateau phase than that induced by 2,4-dinitrofluorobenzene, oxazolone, and imiquimod. Meanwhile, in the animal model induced by urushiol, the changes of epidermal thickening and inflammatory cell aggregation were also more obvious. In addition, pruritus induced by urushiol is prevalent all over the world, especially in the United States and Europe, involving outdoor groups such as firefighters, forest loggers, and farmers. Therefore, we believe that the urushiol-induced animal model is an ideal choice for the study of the itch formation mechanism and the development of antipruritic drugs.