Publication:

Clinico-epidemiological profile and morphological patterns of an institutional outbreak of paederus dermatitis from North India: a descriptive study

Background Paederus dermatitis (PD) is an acute irritant contact dermatitis caused by pederin, a vesicant toxin in the hemolymph of beetles of the genus Paederus. Despite its occurrence across tropical India, published data from north India and documented institutional cluster outbreaks among young adults remain scarce.

Methods A descriptive observational study was conducted at a tertiary care teaching hospital in Greater Noida, Uttar Pradesh, over 15 days in April 2026. All 106 patients clinically diagnosed with PD from a single university hostel campus were consecutively enrolled. Data on demographics, symptom onset, morphological patterns, sites of involvement, and risk factors were recorded using a structured proforma. Descriptive statistics- frequencies, percentages, mean and standard deviation were used for analysis.

Results Of 106 patients (60 males, 46 females), the mean age was 20.27±1.48 years (range 18-24). Mean duration of symptoms at presentation was 1.86±0.74 days. The predominant symptoms were erythema (97.2%) and burning sensation (95.3%). Linear erythematous plaque was the most common morphological pattern (67.9%), followed by kissing lesions (38.7%), herpetiform lesions (38.7%), Nairobi eye variant (21.7%), and erythematous patch with central gray necrotic area (18.9%). The neck was the most frequently involved site (76.4%). Sleeping with windows open (69.8%) and proximity to campus vegetation (100%) were the predominant risk factors.

Conclusions This study reports one of the first institutional cluster outbreaks of Paederus dermatitis from north India, occurring in April- a pre-monsoon season not previously highlighted for PD in this region. The diverse morphological spectrum, including herpetiform and kissing variants, highlighting the importance of clinical awareness to prevent misdiagnosis in hostel settings.