Have You Heard? The danger of the garden hose (transcript)

Ah, those hot summer days—a great time for dog owners to bathe their dirty pooches outside. No danger there, right? A case series out of Texas A&M's Department of Pathology published in Veterinary Dermatology has identified a unique cause behind thermal burns occurring during the dog days of summer.

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10 SUSPICIOUS CASES

Twenty-two skin biopsy samples received during the summer months of 2007 through 2010 had histopathologic findings consistent with thermal burns. Of these, 10 cases had histories suggestive of exposure to hot water from garden hoses. These cases came from areas where the daytime temperatures were known to have reached upward of 90 F before presentation. These cases were typified by injuries along the dorsum; microscopic lesions ranging from local erythema to ulcerated, necrotic, and sloughing skin; and healed alopecic wounds with characteristically smooth glassy scar tissue. Histologically, these injuries represented second- or third-degree burns.

The severity of a burn depends on the temperature and duration of exposure. Biopsy is the most useful tool for diagnosing the type and degree of burn injury. A second-degree burn involves full-thickness epidermal necrosis with extension into the follicular and glandular structures. Third-degree burns take it one step further, with dermal and epidermal necrosis that often 'wicks' down hair follicles to involve the deeper structures.

CAN HOSE WATER GET THAT HOT?

To test the garden hose scalding theory, the pathologists conducted their own field experiment. Two rubber garden hoses—one black and one green—were filled with water and set out on the grass in the hot Texas sun. The hoses spent two hours out in temperatures rising from 89 to 94 F. The water collected from each hose reached a temperature of 120 F—a temperature capable of producing thermal scald injury.

Several criteria should be met before proclaiming a case of garden hose scalding syndrome:

• A clinical history of having been hosed off with water from a garden hose

• Lesions distributed along the dorsum

• Second- or third-degree thermal burns seen grossly and histologically

• Lesions that occurred during the hottest times of the year where the recorded temperatures were above 90 F.

With scalding injuries, clinical signs may not be apparent for several days or even longer after the heat exposure. Pet owners may not be able to remember when or how the injury occurred.

So danger does lurk in the dog days of summer. And this study shows that discussing the possibility of garden hose scalding syndrome with your clients is prudent.

Quist EM, Tanabe M, Mansell JE, et al. A case series of thermal scald injuries in dogs exposed to hot water from garden hoses (garden hose scalding syndrome). Vet Dermatol 2012;23(2):162-166,e33.