An outbreak of Paederus dermatitis in a suburban hospital in South India: a report of 123 cases and review of literature

Morphological and Clinical Patterns of Paederus Dermatitis

Background The objective of the present study was to describe the morphological and clinical patterns of paederus dermatitis (PD). Methodology This retrospective case series was conducted in the outpatient department of the Department of Dermatology, Srinivasan Medical College and Hospital, Trichy, Tamil Nadu, between June 2023 and August 2023 among patients with a clinical diagnosis of PD. Results This study included a total of 10 patients. The mean (SD) age of the patients was 19.4 (1.9) years. More than half of the patients (60.0%) were males. Of the 10 patients included, four (40.0%) were from rural areas, three (30.0%) were from urban areas, and three (30.0%) were from semi-urban areas. The maximum number of cases was reported between June and September. The most common presenting complaint was a burning sensation in 80.0% of the patients, followed by pain in 80.0% and blisters in 20.0% of the patients. The mean (SD) duration of the lesion was 4.2 (1.3) days. Regarding the clinical pattern of lesions, linear lesions were the most common (40.0%), followed by erythematous lesions with central gray area in 30.0%, kissing lesions in 20.0%, and burnt appearance in 10.0% of the lesions. Nearly half of the patients presented with lesions in the face (40.0%), the most common site in the present study, followed by lesions in the leg (20.0%), and lesions in the axilla, chest, arm, and back (10.0% each). Conclusions Understanding the epidemiology and clinical manifestations of this condition is crucial for accurate diagnosis, timely management, and public health interventions aimed at preventing Paederus beetle-related dermatitis.

The insect microbiome is a vast source of bioactive small molecules

Covering: September 1964 to June 2023Bacteria and fungi living in symbiosis with insects have been studied over the last sixty years and found to be important sources of bioactive natural products. Not only classic producers of secondary metabolites such as Streptomyces and other members of the phylum Actinobacteria but also numerous bacteria from the phyla Proteobacteria and Firmicutes and an impressive array of fungi (usually pathogenic) serve as the source of a structurally diverse number of small molecules with important biological activities including antimicrobial, cytotoxic, antiparasitic and specific enzyme inhibitors. The insect niche is often the exclusive provider of microbes producing unique types of biologically active compounds such as gerumycins, pederin, dinactin, and formicamycins. However, numerous insects still have not been described taxonomically, and in most cases, the study of their microbiota is completely unexplored. In this review, we present a comprehensive survey of 553 natural products produced by microorganisms isolated from insects by collating and classifying all the data according to the type of compound (rather than the insect or microbial source). The analysis of the correlations among the metadata related to insects, microbial partners, and their produced compounds provides valuable insights into the intricate dynamics between insects and their symbionts as well as the impact of their metabolites on these relationships. Herein, we focus on the chemical structure, biosynthesis, and biological activities of the most relevant compounds.

An Outbreak of Paederus Dermatitis in a Suburban Hospital in Southwest China: A Report of 134 Cases and Review of Literature

Reports of paedoptera dermatitis are commonly found in tropical and subtropical regions, while reports in China are rare. In September 2022, an outbreak of paedoptera dermatitis occurred in a minority autonomous county in southwestern China. Here, we report 134 patients with paedoptera dermatitis who were treated at the People's Hospital of Sandu Shui Autonomous County. The skin lesions of these patients were mostly located on the face, neck, trunk, or multiple sites. The skin lesions were mainly distributed in patches and were characterized by vesicular linear or "kissing" lesions. Most patients felt burning pain, and few patients felt pruritus. The treatments with oral antihistamines, calamine lotion, steroids, and antibiotics were effective. For patients with ocular involvement, treatments with oral prednisone and bufexamac cream were effective. All patients recovered within 2 wk. There is a possibility of another outbreak of paedoptera dermatitis in the region. Awareness of the condition and its clinical features will prevent misdiagnosis. Early diagnosis and timely treatment lead to a better prognosis for paederus dermatitis. Simple preventive measures can be undertaken based on the behavioral pattern of this nocturnal beetle.

The Nairobi fly in the Himalayas

The Nairobi fly has been sighted in the sub-Himalayan range with an outbreak of Paederus dermatitis in Nepal, Bhutan and north-eastern India in 2022. With increasing international travel and a warmer earth, tropical vectors in non-native regions are an emerging global health challenge.

Erythroderma and Skin Desquamation in Paederus Dermatitis

Exfoliative erythroderma is rare but serious condition, which requires close supervision. We report a rare case of 28-year-old man with kissing lesions of Paederus dermatitis at his right side of neck. The rash caused by Paederus beetle was improved after treatments. However, the patient developed generalized erythema with desquamation and scaling. The patient was successfully treated topically with moisturizing liquid soap and topical moisturizer with emollients and humectants, and triamcinolone lotion was applied on the bright red lesion. The patient was also treated with oral replacement solution and tropical azelaic cream was applied on the hyperpigmented kissing lesion. This case report shows the importance of a diagnostic practice with follow-up examination.

Paederus Dermatitis Outbreak in Addis Ababa, Ethiopia: A Case-Control Study

Background

Paederus dermatitis is an irritant contact dermatitis caused by crushing insects of the genus Paederus, which releases a vesicant toxin called pederin. On July 28, 2018, the district health office received a report of cases with erythema, itching, and burning after contact with the Paederus insect. In response, we investigated the outbreak intending to describe, confirm, and identify the risk factors associated with the country's first reported outbreak.

Methods

A community-based unmatched case-control study was conducted from August 10 to 22, 2018. Two hundred twenty-five (75 cases and 150 controls) study participants were involved in the study. Cases were defined as Bole subcity residents who had acute contact dermatitis after contact with the insect, while controls were persons who did not have contact with the insect. Cases were recruited consecutively as they present, whereas controls were selected by the neighborhood sampling method. An interviewer-administered questionnaire was used for the data collection, and multiple logistic regression was applied to determine the independent risk factors. The results were expressed as adjusted odds ratios (AORs) and 95% confidence intervals (CIs).

Results

A total of 122 cases were reported from the three districts of the subcity. The mean age of cases and controls was 23.6 (SD ± 16.4) and 29.4 (SD ± 10.9) years, respectively. Multivariate analysis showed that the presence of outdoor light (AOR = 5.1; 95% CI (2.5, 10.9), presence of rotten leaves (AOR = 6.4; 95% CI (2.9, 15.7)), sleeping on the floor (AOR = 6.1; 95% CI (2.5, 15.7)), wearing protective clothing (AOR = 0.2; 95% CI (0.1, 0.4)), and use of insect repellant (AOR = 0.1; 95% CI (0.0, 0.4)) were significantly associated with Paederus dermatitis outbreak.

Conclusion

The investigation identified exposure to artificial light and the presence of rotten leaves around the residential area as important factors leading to an increase in the odds of Paederus dermatitis. In contrast, the use of insect repellant and wearing protective clothing were shown to provide protection. The investigation determined that reducing burning outdoor lights, cleaning excess vegetation, avoiding sleeping on the floor, using insect repellants, and wearing protective clothing can reduce the risk of contracting Paederus dermatitis.

Evaluation of Lymphocyte Migration to Induced Paederus Dermatitis: An Experimental Study in Rats

Background:

Paederus dermatitis (PD) is a blistering disorder that is caused by a small insect of the genus Paederus, especially Paederus fuscipes. This study aimed to investigate the reaction of the adaptive immune system regarding the recruitment of CD3, CCR4, and CCR10 markers, which are specifically expressed on the surface of T lymphocytes.

Materials and Methods:

In this experimental study, 24 female rats were divided into two groups: the test and the negative control. In the test group, PD was induced by making insects in contact with shaved rat skin. Biopsies were obtained 24, 72, and 120 h after induction. In the negative control group, physiological saline was applied. Specimens were evaluated by immunohistochemical staining method. Antibodies against CD3, CCR4, and CCR10 were used. Distribution and staining intensities of CD3, CCR4, and CCR10 markers were estimated by the H-score index and findings were analyzed using the Kruskal–Wallis and Wilcoxon statistical tests.

Results:

Based on the results of immunohistochemistry, the expression of CD3, CCR4, and CCR10 in the test group at 24, 72, and 120 h compared to the control group showed significant increase (P = 0.0006, P = 0.001, and P < 0.0001), respectively. The peak of expression of all markers was at 72 h after exposure. Hematoxylin and eosin staining also confirmed the fact that the majority of the lymphocyte infiltration occurred at 72 h postexposure.

Conclusion:

The expression of CD3, CCR4, and CCR10 on cells present in PD lesions could indicate that T-lymphocytes are recruited to the site of inflammation by chemokine–chemokine receptor interactions and hence provide evidence for the response by the adaptive immune system following a PD.

Dermatitis Due to Paederus Colombinus: Report of an Epidemic Outbreak of 68 Cases in the Province of Darien, Panama

Introduction

Contact dermatitis due to Paederus is a particular form of accident by animal contact. It is characterized by the sudden onset of erythematous and vesicular lesions with burning sensation on exposed areas of the body. The aim of this study was to describe the epidemiological and clinical findings of an outbreak of Paederus dermatitis in Panama.

Methods

Clinical and epidemiological findings of an outbreak of contact dermatitis caused by Paederus sp. in the province of Darien in eastern Panama is reported. After reviewing the clinical records, a clinical-epidemiological questionnaire was developed and used in 20 communities where reported cases were found. We captured and collected the specimens for species characterization for three consecutive days using three different methods of capture.

Results

During May-July, 2014, 68 cases of Paederus irritant contact dermatitis occurred in 20 communities of the Darien. Fifty-three percent were females. The age group of zero to five years had the highest number of cases, 15 (22%). The most common clinical presentation was the classical linear dermatitis (58%); 42% of the subjects had mirror image lesions, multiple vesicular-pustular lesions, and crust lesions. Symptoms were most commonly reported as a burning sensation (65%), followed by pruritus in 60%, pain (25%), and fever (nine percent). A total of 81 specimens of Paederus were collected, 68% in peridomiciliary areas.

Conclusions

This Paederus sp. dermatitis report represents one of the largest outbreak described in Latin America and the diagnosis could be confused with others skin diseases like pyodermitis or other contact dermatitis.

Attraction factors for Paederus fuscipes ' dispersal, a vector of Paederus dermatitis towards human residential premises

Paederus fuscipes, a vector of Paederus dermatitis in most tropical and subtropical countries of the world have a high prevalence in human dwellings due to their positively phototaxic behaviour which has caused a tremendous impact on human health. In this paper, P. fuscipes dispersal flights were studied for two seasons of the rice cultivation phases in residential premises built close to rice field areas (≈32-60 m and 164 m) in mainland Penang, Malaysia. We examined the effects of different light illuminance, building floor level and their association with rice stages as a focal cause of P. fuscipes dispersion from the rice fields towards human dwellings. The present study showed a significant interaction between different light illuminances and rice cultivation phases in attracting P. fuscipes to disperse and invade human dwellings. The highest number of P. fuscipes was captured near the bright light. P. fuscipes flights increased in line with each floor level, and the highest captures took place at higher building floor levels (levels 2 and 3) compared to lower building floor levels (ground floor and level 1) of a three storey apartment in both rice seasons. This finding not only conveys a better understanding on P. fuscipes dispersal pattern, but also draws public attention on the occurrence of dermatitis linearis caused by the Paederus beetles.

Clinical and Epidemiological Features of Paederus Dermatitis Among Nut Farm Workers in Turkey

Paederus dermatitis is an acute irritant dermatitis resulting from contact with the hemolymph of Paederus beetles. This dermatitis mimics other infectious skin disorders, often resulting in diagnostic dilemmas. This study of 46 patients was conducted to increase awareness about Paederus dermatitis. Possible causes of a number of cases of Paederus dermatitis in Giresun, Turkey, were investigated using climate data and telephone interviews with the patients about risk factors. Insects caught by patients were identified at the species level. All patients were hazelnut farm workers and admitted to the hospital in the months during which the hazelnut harvesting occurs. Of the patients, 11 (23.91%) presented with painful and burning skin lesions, and 35 (70.09%) complained of itching. The neck was the most involved site (47.83%). The predominant type of lesion was erythematous plaque (84.78%). No pathological findings were detected by laboratory testing. Patients reported coming into contact with the insect during the daytime. Captured insects were identified as Paederus fuscipes. Although the weather and climate were optimal for P. fuscipes during June-October, patients were admitted to the hospital only during the hazelnut harvesting season (August-September). The only risk factor identified among patients was occupation; hence we believe our study is the first to suggest that Paederus dermatitis is an occupational disease among hazelnut farm workers. We suggest that Paederus spp. may become a substantial threat due to global warming, especially among farm workers. Paederus dermatitis is not included in classic medical textbooks. It is necessary to increase awareness about this condition.

Ophthalmic manifestations of Paederus dermatitis

PURPOSE

To report the pattern of ophthalmic manifestations associated with Paederus dermatitis (PD).

SETTING

Department of Ophthalmology, Sri Guru Ram Das Institute of Medical Sciences and Research, Amritsar, India.

DESIGN

Clinic-based retrospective study.

METHODS

Medical charts of patients presenting to the eye clinic with clinical features consistent with the diagnosis of PD from May 1, 2014 to April 30, 2016 were retrospectively reviewed. Relevant demographic and clinical data of periocular and ocular findings were collected and analyzed. The patients with a history of chronic skin disorders or allergies were excluded from the study.

RESULTS

A total of 56 patients were included in the study, of which 39 (69.6 %) were males. The age range was 4-65 years with a median of 27 years. On presentation, common subjective symptoms were burning sensation in 49 (87.5 %), itching in 37 (66.1 %), watering in 25 (44.6 %), foreign body sensation in 19 (33.9 %), blurring of vision in 17 (30.4 %), and photophobia in 12 (21.4 %) patients. Visual acuity at presentation was 20/20 in 39 (69.6 %) patients, between 20/30 and 20/80 in 9 (16.1 %) patients, and less than 20/80 in 8 (14.3 %) patients. Lid swelling, erythema, crusts, and vesicles were the common periocular findings; and conjunctival hyperemia, discharge, and corneal erosions were the common ocular findings.

CONCLUSIONS

The current study shows that PD can cause significant ocular morbidity. Ophthalmologists, especially those who work in endemic areas, should be aware of this entity both in terms of management as well as for educating patients about the preventive measures.

Paederus dermatitis in a seafarer diagnosed via telemedicine collaboration

Seafarers are traveling workers, subject to unique exposures and generally isolated from adequate medical care. This case report of paederus dermatitis diagnosed at sea highlights the importance of a multidisciplinary diagnostic approach and telecommunication in providing remote medical advice to isolated traveling workers such as seafarers.

[Blister beetle dermatitis: Dermatitis linearis]

Several families of beetles cause toxic reactions on exposed human skin. Cantharidin provokes nearly asymptomatic vesicles and blisters, while pederin leads to itching and burning erythema with vesicles and small pustules, later crusts. Paederi are attracted by fluorescent light especially after rain showers and cause outbreaks in regions with moderate climate. Clinical findings and patient history lead to the diagnosis: dermatitis linearis.

[Vesicular contact dermatitis due to Paederus in Cameroon and review of the literature]

This irritant blister dermatitis is caused by the genus Paederus whose geographical distribution is worldwide, with a higher incidence in tropical areas. It is induced by direct skin contact with pederin, a blistering and caustic substance found in the abdomen (coelome) of Paederus insects (insect order Coleoptera: family Staphylinidae). The diagnosis is based on the presence of typical clinical features combined with compatible epidemiological features. Our goal is to describe the epidemiological and clinical features of this irritant contact dermatitis in Cameroon through a retrospective study conducted at the end of the rainy season at the Oku Hospital in Northwest Cameroon and to also include cases reported at the medical center of the French Embassy in Yaounde during this same timeframe. In addition, we conducted a literature review of paederus dermatitis. Nineteen patients were included in this study. More than half of the patients presented with more than two lesions predominantly localized to the face or the neck; less than half had complications manifesting as either localized or respiratory reactions and three patients presented periorbital involvement. This study confirms the presence of paederus dermatitis in Cameroon. It is mainly localized in the unusual geoclimatic region of the western high mountains within the country, as well as the usual warm, moist areas of Yaounde. The clinical evolution of this dermatitis is usually one of spontaneous and uneventful resolution with complications being rare. Curative treatment is one of localized topical therapies while oral antibiotic therapy should be reserved for more complicated cases.

Paederus Outbreaks in Human Settings: A Review of Current Knowledge

Although rove beetles (Paederus spp.) play a beneficial role as biological control agents to manage crop pests in agro-ecosystems, their high prevalence in human settings has elevated them to pest status in urban areas. Rove beetles neither bite nor sting, but accidental crushing on human skin causes them to release the toxin paederin, which causes dermatitis linearis. This review integrates currently available knowledge about the issues pertaining to Paederus infestation. For instance, the results of life history studies conducted under different food and temperature regimes are summarized, as they indicate how large a population can be in a habitat to cause massive and widespread infestation and illustrate the physiological traits required to maintain the population at the maximum level even under adverse conditions. In contrast to what is generally reported, we speculate that climatic factors do not necessarily result in Paederus dispersal in temperate regions; instead, habitat disturbance and site unsuitability may be the main factors that lead to massive dispersal to human settings. Factors such as whether dispersers are adaptable to xeric conditions in human settings, the probability that dispersed Paederus mate with the opposite sex, and whether dispersers have adequate nutrient intake to reproduce are considered to evaluate their potential to reproduce in human settings. Finally, the effectiveness of current commercial insecticides, challenges faced in managing infestations, and sustainable management practices are discussed to provide information for long-term control programs.

Paederus dermatitis featuring chronic contact dermatitis

Paederus dermatitis is a distinct variant of acute irritant contact dermatitis caused by mucocutaneous contact with the specific toxin of an insect belonging to the genus Paederus. It is characterized by the sudden onset of erythema and vesiculobullous lesions on exposed skin, with special predilection for the periorbital region. Paederus species have been mostly identified in Africa, Asia, Australia, and Central/South America. We report a 51-year-old woman who experienced 4 recurrences of periorbital erythema and edema in the previous year. No consistent etiology could be established at the beginning. Only after taking a detailed medical history was it discovered that 1 year before our examination, the patient had traveled to Kenya, where she had experienced contact with the insect. This fact led us to the diagnosis of Paederus dermatitis. After appropriate treatment, a complete regression was observed over a 3-week period.

Dermatitis linearis: vesicating dermatosis caused by paederus species (coleoptera: staphylinidae). Case series and review

OBJECTIVE

Outbreaks of dermatitis linearis have been documented worldwide. We present a case series of dermatitis linearis from Latin America to highlight the importance of this clinical entity. Clinical, historical, epidemiological, and pathological aspects of the condition are discussed, and a concise current approach to the management and treatment of this morbidity is presented.

METHODS

We present a series of 4 selected cases reflecting the clinical spectrum exhibited in dermatitis linearis by Paederus along with a review of the literature.

RESULTS

In this review we demonstrate the need for awareness of dermatitis linearis as a clinical entity that must be considered in the broad list of differential diagnosis embracing vesicating linear lesions.

CONCLUSIONS

Capture of the insect, epidemiologic features, and a high clinical suspicion can aid in making the correct diagnosis. Primary prevention through public awareness, decreased use of artificial lighting, and mosquito nets can limit the extent and severity of outbreaks.

Nairobi fly (Paederus) dermatitis in South Sudan: a case report

A 28-year-old nursing student working in Juba, South Sudan, suddenly developed a rash over her mid-right clavicle. Beginning as a 10-cm-diameter erythematous patch with an irregular border, within 24 hours it had developed an increasingly gray, necrotic center, appearing similar to a burn. The patient was seen by 2 local physicians without a diagnosis being made. Ultimately, it was diagnosed as being caused by the toxic hemolymph, pederin, from the Nairobi fly (Paederus). The rash usually affects body parts not covered by clothing; healing time ranges from 7 to 28 days, usually with permanent skin discoloration. Preventive measures include typical antivector precautions, including bed nets, long-sleeve clothing, and avoiding fluorescent lights. If the beetles are found on the skin, brushing them off, rather than crushing them, avoids producing dermatitis. Treatment includes rapidly washing the affected area, applying cold, wet compresses, and possibly treating with antibiotics, steroids, and antihistamines.

Life table of Paederus fuscipes (Coleoptera: Staphylinidae)

The life history characteristics of the rove beetle Paederus fuscipes Curtis were studied under laboratory conditions using three field strains from Malaysia: Desa Wawasan (DW), Sri Pinang (SP), and Ampang Jajar (AJ). The total development time of immature stages differed significantly among the three strains, especially between DW (17.43 +/- 0.16 d), SP (18.60 +/- 0.19 d), and AJ (18.68 +/- 0.22 d). Adult females and males from DW also exhibited a shorter life span, although the difference among strains was not significant. In terms of fecundity, the numbers of eggs laid per female for DW, SP, and AJ were 121.28 +/- 15.98, 127.30 +/- 18.01, and 147.45 +/- 17.12, respectively. Additionally, because of the shorter life span in DW strain, two apparent peaks in age-stage specific fecundity were detected. The beetles compensated for their shorter life span by increasing their reproductive activity to sustain the progeny in the population. The intrinsic rates of increase (r) of P. fuscipes from DW, SP, and AJ were 0.0773 +/- 0.0046 d(-1), 0.0788 +/- 0.0051 d(-1), and 0.0873 +/- 0.0054 d(-1), respectively; and the net reproduction rates (R0) were 40.09 +/- 7.39 offspring, 45.29 +/- 8.74 offspring, and 42.34 +/- 8.25 offspring, respectively. The mean generation time of P. fuscipes from AJ was 43.08 +/- 1.07 d, which was significantly higher than that from DW (47.95 +/- 1.36 d) and SP (48.57 +/- 1.43 d). The total immature development time of P. fuscipes in this study was shorter than values reported in previous studies.

Irritant bullous contact dermatitis caused by a rove beetle: an illustrated clinical course

A 26-year-old Australian female traveller in Sierra Leone presented with an irritant bullous contact dermatitis consistent with paederus dermatitis. The lesions were treated with a potent topical corticosteroid with good effect. The affected area resolved in 6 weeks and hyperpigmention persisted for months until complete resolution. This dermatitis occurs when beetles of the genus Paederus (rove beetles) are crushed on the skin, releasing pederin. The same dermatitis ensues with Australian Paederus species. Serial clinical photographs are presented which will aid Australian dermatologists in the diagnosis of this dermatitis, which presents in regional Australian patients and returned overseas travellers.

Comparison of topical triamcinolone and oral atorvastatin in treatment of paederus dermatitis Northern Iran

Dermatitis caused by stimulation of beetle paederus, is a common health problem in Northern and some southern parts of Iran. Since by now, traditional medicine and some corticosteroid agents have been used for treatment of dermatitis caused by beetle paederus. Because, there are few researches about classical treatment of the disease at academic level, this study planned to compare the effectiveness of triamcinolone ointment and atorvastatin tablet with placebo in treatment ofpaederus dermatitis in Northern Iran. A randomized double-blind clinical trial was carried out on 30 patients referred to the hospital and clinics at Sari and Neka countries in Northern Iran during 6 months. Patients were randomly divided into two therapeutic equal groups. The first group was triamcinolone ointment twice a day and a placebo atorvastatin tablet daily. The second group was oral atorvastatin one tablet (20 mg) daily and a placebo triamcinolone ointment twice a day. In Seventh day of visits, therapeutic response of the patients in triamcinolone and atorvastatin group were 93.33 and 80%, respectively. No significant differences were found in therapeutic outcome between the two groups (p > 0.05). The results showed both oftriamcinolone ointment and oral atorvastatin had similar effect on paederus dermatitis. Because the paederus dermatitis is a self-limited disease use of topical therapy for treatment of the disease is recommend.

Paederus dermatitis in Egypt: a clinicopathological and ultrastructural study

BACKGROUND

Outbreaks of paederus dermatitis (PD) have been observed in different parts of the world, yet the histopathological and ultrastructural changes and their relationship to pederin toxin have not been described.

OBJECTIVE

To describe the clinical presentations of PD in Egypt and to study the effects of pederin toxin on the skin by evaluating the histopathological and ultrastructural changes of some representative cases.

METHODS

One hundred and thirteen patients with PD were studied clinically and epidemiologically. Skin biopsies were taken from 40 patients for histopathological examination and from 20 patients for electron microscopic (EM) examination.

RESULTS

Clinically, the most common presentation comprised erythematous plaques with micropustules. Blisters exhibited a linear configuration in 40% of the patients and kissing lesions were observed in 13%. Multiple lesions occurred in 78% of the patients and the face was the most commonly involved site (48%). The insect was identified as Paederus alfierii. Histopathological examination revealed features of acute irritant dermatitis in the upper epidermis. Mitotic figures and apoptotic changes such as chromatin condensation and DNA fragmentation were identified in the basal and suprabasal layers. These features were confirmed by EM.

CONCLUSIONS

Clinical, histopathological and, for the first time, ultrastructural characteristics of paederus dermatitis are described. The pathological abnormalities of the upper epidermis are caused by the irritant effect of pederin toxin. The presence of apoptosis within the lower epidermis can be related to this toxin, a point that needs further research, hoping for its future implications in the management of hyperproliferative disorders.

An outbreak of 268 cases of Paederus dermatitis in a toy-building factory in central China

OBJECTIVE

To evaluate the clinical features of and to identify the pathogen responsible for an outbreak of acute dermatitis in a toy-building factory in Chibi city, central China.

METHODS

Physical examinations were carried out on all the factory staff. Records were made. The factory district, its surrounding environment and the accommodation conditions were investigated. The insects collected in the area were identified by a parasitologist at the Department of Parasitology, Tongji Medical College, Huazhong University of Science and Technology, Wuhan.

RESULTS

Two hundred and sixty-eight cases of Paederus dermatitis were diagnosed in a total of 316 staff at the toy-building factory. The total incidence rate was 84.81%. The incidence rates in administrators and workers were 43.75% and 87%, respectively. The face and neck were the most common sites of involvement. The most common lesions consisted of linear erythema and papulopustules. In 71.27% of patients, more than one lesion was present.

CONCLUSION

This outbreak of acute dermatitis was diagnosed as Paederus dermatitis caused by Paederus fuscipes. The favorable environment, lighting, humidity, and poor accommodation may have been responsible for the outbreak. Increased public awareness of this condition may decrease the incidence of Paederus dermatitis.