A Clinico-Epidemiological Study of Paederus Dermatitis in a Tertiary Care Center in Puducherry, India : Indian Dermatology Online Journal

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A Clinico-Epidemiological Study of Paederus Dermatitis in a Tertiary Care Center in Puducherry, India

Palaniappan, Vijayasankar; Karthikeyan, Kaliaperumal

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Indian Dermatology Online Journal ():10.4103/idoj.idoj_451_22, May 25, 2023. | DOI: 10.4103/idoj.idoj_451_22
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Dear Editor,

Paederus dermatitis (PD) is an acute irritant contact dermatitis caused due to contact with beetles (Order: Coleoptera, Family: Staphylinidae, Genus: Paederus). It is common in tropical and subtropical regions with hot and humid climates.[1,2] In India, PD has been reported from Tamil Nadu, Punjab, Rajasthan, Odisha, and West Bengal.[3] P. fuscipes is the most common species implicated in Southern parts of India.[4] Puducherry is located on the Coromandel Coast of the Bay of Bengal and has a tropical wet and dry climate with high humidity which is perfectly apt for the survival of Paederus beetles. This study aims to know about the epidemiological and clinical features of PD in Puducherry, located in Southern India.

In this clinico-epidemiological study, 320 cases of PD that fulfilled the criteria devised by Karthikeyan and Kumar were included.[1] The socio-demographic details, housing information, and clinical details of the patients were collected using a pre-designed questionnaire. The patients were shown an image of the Paederus beetle to know their familiarity with it

The patients were treated with topical antibiotic and steroid combination creams, antihistamines, and cold compresses. In extensive cases, systemic antibiotics were administered. The patients were also provided health education regarding the preventive measures to avert similar future episodes. Descriptive statistics such as means and standard deviations of quantitative variables and frequencies (%) of qualitative variables were computed.

The mean age of the patients was 37.4 ± 15.8 years (range: 12 to 76 years). There were 204 males (63.7%) and 116 females (36.3%). One hundred and ten (34.3%) patients stated that they slept with their windows open at night and 194 (60.6%) patients slept on their floors before the development of PD. Five (1.5%) of our patients used mosquito bed nets at the night, and only two (0.6%) used insect-repellent creams. The demographic features of patients with PD are mentioned in Table 1. Only two (0.6%) of the people who were given the photograph of the Paederus beetle remembered contact with it before to developing the lesion. Twelve people (3.75%) recognised the existence of similar bugs close to their home.

Table 1:
Distribution of Paederus dermatitis based on the type of housing, lighting, agricultural fields, and seasonal occurrence

The skin lesions were present from 1 to 9 days before the consultation (mean duration 2.4 ± 1.9 days). Family history of PD was ascertained in 10 patients (3.1%). One hundred and eighty-two (56.8%) patients presented with a single lesion, 46 (14.3%) patients had two lesions, 18 (5.6%) patients had three lesions, and 74 (23.1%) patients had more than three lesions. The clinical features of patient with PD in our study are mentioned in Table 2. Keratoconjunctivitis was observed in four (1.2%) of our patients. Fever and malaise were observed in one patient who was managed with antipyretics and oral antibiotics in addition to skin management.

Table 2:
Clinical features of Paederus dermatitis in our study

There are no epidemiological data about the prevalence of PD in Pondicherry, but it is one of the commonly encountered problems. The majority of our patients belong to rural areas, rich in agricultural fields and marshes, the natural habitat of the Paederus beetle. An increased incidence of PD was observed during the monsoon and immediate post-monsoon season in this study. It is consistent rice field activities such as harvesting and plowing in our region during that time. These disturbances in the habitat pose a serious threat to Paederus beetles thereby triggering its dispersal and increased infestation of humans.[5]

The beetles are more active at night, and accidental crushing of the beetles during sleep time is the most prominent form of exposure. Hence, the lesions are usually observed on awakening in the morning and hence termed a “wake and see” disease in Nigeria.[1] Our study also substantiates this finding as 78.7% of our patients noticed the lesions in the morning. A majority of our patients were residing in kutcha houses, which favor the entry of Paederus beetle. In our study, 60.6% had the habit of sleeping on the floors, a possible risk factor for PD as the beetles prefer to run along the ground.[1] A similar finding was observed in a military camp, and among nut farmers in Turkey.[6,7] The epidemiological data of PD patients in our study are mentioned in Table 1.

Similar to other studies, the face and neck were the most common sites involved in our patients.[8,9] The exposed sites have a high level of susceptibility to PD as it does not have a shade to prevent coincidental interaction with the irritant. Dermatitis linearis is the most common morphological lesion observed in our area similar to other studies.[8,10] Various morphological patterns encountered in our study are shown in Figures 1-3. The salient clinical features observed in our patients are mentioned in Table 2.

Figure 1:
(a) Dermatitis linearis (b) Kissing lesion
Figure 2:
(a) Localized pustular dermatitis (b) Erythematous plaque with erosion
Figure 3:
(a) Burnt out appearance (b) Periocular paederus dermatitis

A majority of the patients did not have enough knowledge about dermatitis caused by the Paederus beetle similar to a study conducted in Turkey.[11] Educating the patients about simple preventive measures such as recognizing and avoiding crushing the beetle, closing and covering the windows with screens, utilizing permethrin-treated bed nets, minimizing the use of fluorescent lights, avoiding standing directly under the lights, and draping nets under the lights to prevent fall on humans should be done. When working in an area with high prevalence, wearing long-sleeved shirts and hats is helpful. Clearing the excessive vegetation from and around the residence and regular use of preventive pyrethroids sprays and 50% malathion in infested areas can help in decreasing the incidence of PD.[1] The limitation of our study is that a skin biopsy of the lesions was not performed.

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Conflicts of interest

There are no conflicts of interest.


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