Control of the rove beetle in rapidly deployed Ebola treatment units (ETUs) is necessary for worker safety.

Paederus dermatitis, alternatively called blister beetle dermatitis, Nairobi fly “bites,” and Kenya fly dermatitis, is a form of irritant contact dermatitis that is prevalent in the tropics.1, 2 Blister beetles are well known in dermatology where the vesicant property of cantharidin is used for the treatment of molluscum contagiosum. Outbreaks of Paederus dermatitis were a common and feared complication among workers in Ebola treatment units (ETUs) in several locations in Liberia. We present a case of a health care worker who developed Paederus dermatitis while working in an ETU in Liberia. The severity of the dermatitis required that he be taken out of the work rotation because of concern that the open skin increased the risk of Ebola to the affected health care worker. Protection of skin and mucous membranes was a priority for aid workers during the Ebola epidemic and included monitored full-body coverage and chlorine solution spraying before disrobing. Control of the rove beetle in facilities that house Ebola health care workers should be a priority.

Case report

A 64-year-old Caucasian male worker in an ETU in Kakata, Liberia felt a burning sensation on the right antecubital fossa in the middle of the night. He awoke with a circumscribed vesiculobullous eruption from a rove beetle crush injury (Fig 1, Fig 2, Fig 3). He immediately washed the area and applied hydrocortisone 1%. Later that day, he applied clobetasol. The cutaneous eruption persisted for over a week and healed with residual scarring. He was taken out of the work rotation as a result of concern that the open wound increased the chance of transmission of Ebola to the affected health care worker. The beetles were easily recognized among the workers in the ETUs, being small (7-10 mm long and 0.5 mm wide) with vivid orange bodies and front wings.1, 4 They were commonly seen crawling along the rafters of the work tents and portable latrines. The beds in Kakata did not have mosquito netting.

Fig 1

Right antecubital fossa (day 1) with a circumscribed vesiculobullous eruption.

Fig 2

Right antecubital fossa (day 2) with a circumscribed vesiculobullous eruption.

Fig 3

Right antecubital fossa (day 4) showing healing with postinflammatory hyperpigmentation after treatment.

Discussion

Paederus dermatitis occurs when the rove beetle is accidently crushed against skin. This trauma triggers the release of pederin, leading to development of vesicular inflammatory dermatitis in 12 to 36 hours.2, 5 The clinical presentation can be variable and include erythematous plaques that appear burnt, micropustules mixed with vesicular lesions, significant epidermal necrosis, diffuse desquamative reactions, systemic IgE-mediated hypersensitivity reaction, and juxtaposed skin lesions at flexural folds known as “kissing lesions.” These lesions may heal in 10 to 12 days and often have residual postinflammatory hyperpigmentation.

The dermatitis can be limited if affected skin is washed with soap and water as pederin penetrates into the skin very slowly. If initial skin lesions do occur, cold compresses, calamine lotion, or topical corticosteroids are recommended. In 1 observational study of 50 patients with severe dermatitis, patients responded well to several regiments: oral prednisolone (30 mg once daily for 7 days); intralesional triamcinolone; or a combination of twice-daily topical diflucortolone (0.001%), once daily cetirizine (10 mg), and twice daily ciprofloxacin (500 mg). Of note, healing time was shorter in the subgroup that received ciprofloxacin, possibly because of the presence of secondary bacterial infection. An Iranian study of 30 patients found no difference between oral atorvastatin 20 mg a day with triamcinolone ointment twice daily to atorvastatin only.

The Ebola epidemic in West Africa provoked a massive and rapidly deployed international undertaking to control the spread of the disease. Individuals working in ETUs were given extensive orientation on proper dress and disrobing procedures to prevent Ebola contamination. In the future, attention to other percutaneous risk factors, such as skin disruption from Nairobi fly bites, may be included in health care worker orientation. Those tasked with the rapid establishment of temporary facilities to house aide workers may want to use bug-resistant light sources and netting in latrines and designated sleep areas. Control of rove beetle injury is necessary to protect against highly infectious diseases that are transmitted through the skin.