Heatwave and heatwave: beware of burns on overheated sidewalks

This is the story of a 56-year-old man suffering from alcoholism who was referred to a burn center for treatment of burns to his feet. He walked barefoot on the asphalt for a minute while intoxicated. This happened on a day when the city of Seattle was experiencing the effects of a heat dome, responsible for a heatwave during which maximum air temperatures reached 42°C, about 21°C above historical averages.

Referred to the emergency room, this patient is experiencing severe pain. He has open blisters with oozing and redness (erythema) on the soles of both feet, the plantar surface of the toes of the right foot, and on the heel of the left foot. An intact blister is also present on the right heel . The diagnosis is clear: second-degree burns caused by the hot road surface.

The fifty-year-old man received pain relief, wound cleaning to remove all damaged and necrotic tissue (debridement), antibiotic treatment (bacitracin), and an antimicrobial foam dressing. At a follow-up visit after 18 days, his burns had healed without complications.

This clinical case occurred during the June-July 2021 heatwave in western North America. It was reported in the American medical weekly The New England Journal of Medicine in April 2025.

Those most at risk for this type of burn include those who lie on the sidewalk (homeless), walk barefoot on hot pavement, fall accidentally or after fainting, or collapse on the overheated ground during a seizure or after taking alcohol or drugs. Other risk factors include severe diabetic peripheral neuropathy, which may prevent a patient from feeling the burn when walking on very hot pavement.

Burns that occur as a result of contact with overheated floors result in longer hospitalizations, more frequent surgery, and higher costs per burned area compared to burns of equivalent size caused by boiling liquid or flame.

Sidewalk burns are deeper than their initial appearance suggests and continue to worsen during hospitalization. This progression is likely related to the prolonged pressure exerted on the wounds while lying down, as they are often located on pressure points.

Furthermore, studies have shown that an altered state of consciousness, such as that observed during heatstroke, is associated with a poorer prognosis in patients with this type of burn, with an increased risk of mortality at 30 days.

Pavement burns were first described in 1970, and a detailed analysis of their occurrence was published in 1995. At that time, these clinical observations were reported by burn center teams in Arizona. Since then, pavement burns have been reported in regions and countries known for their hot climates, such as Arizona and New Mexico, as well as in Israel.

A "sidewalk burn" is a specific type of burn caused by prolonged contact with a surface exposed to sunlight during high ambient temperatures. These surfaces can be asphalt, concrete, brick, metal, or any other surface continuously exposed to direct sunlight. In desert conditions, where the sun shines almost continuously and summer temperatures are high, the ground can become hot enough to cause contact burns.

In 2022, surgeons at the Las Vegas Medical School showed that at an ambient temperature of 38°C, asphalt can reach 55°C. At 40°C, it can exceed 66°C and be hot enough to cause second-degree burns in less than 35 seconds.

These doctors had previously reported that hospital admissions for sidewalk burns increase when ambient temperatures exceed 35°C and increase exponentially as ambient heat increases.

The same team also observed that patients with documented hyperthermia at the time of admission had significantly higher 30-day hospital mortality, a greater number of days in intensive care, more surgical interventions, and a higher percentage of body surface area burned. Thus, hyperthermic patients had a 30-day hospital mortality of 30%, compared to 1.3% in the normal body temperature group. The average body surface area burned was 10% in the hyperthermic group, compared to 4.6% in the normal temperature group.

Published in 2023 in the Journal of Burn Care and Research , a study by the same Las Vegas team was conducted to identify the types of pavement reaching the highest temperatures in a hot desert climate, measure the maximum temperature of commonly sun-exposed surfaces with which patients may come into contact, and determine the time of day when the risk of burns is highest. The temperature readings were recorded on August 6, 2020, at 2 p.m., when the ambient temperature was 48.9 °C and the solar irradiance was 940 W/m², which corresponds to a very high thermal and light intensity, close to the maximum that can be received at noon on a perfectly clear sky.

The maximum temperature recorded was 76.7 °C on porous rock, followed by 74.4 °C on asphalt, 66.7 °C on brick, 62.2 °C on concrete, 62.2 °C on metal, and 61.7 °C on sand. The maximum temperature on all materials was reached only after a duration of exposure to ambient heat of 13 to 14 hours. It was recorded in the mid-afternoon: between 1 p.m. and 4 p.m. for sand, porous rock, and metal, and between 2 p.m. and 4 p.m. for asphalt, brick, and concrete.

In the shade, none of these materials reached the threshold of approximately 43.3°C, necessary to cause a burn. In this case, the maximum temperatures were significantly lower, between 40.0°C and 42.2°C.

Paul Chestovich and colleagues (Las Vegas) point out that "all surfaces can cause second- or third-degree burns (depending on the duration of contact) in the presence of high ambient temperature or intense sunlight, but it is the combination of the two that results in surface temperatures high enough to cause contact burns."

These authors note that at the end of the day, the lower solar intensity is paradoxically accompanied by still-high surface temperatures, due to the ability of materials to absorb and store heat throughout the day. "In a desert climate, this phenomenon can be observed by feeling the heat released from the ground and hard surfaces well after sunset. Surfaces exposed to the sun did not return to their initial temperature until 9 to 11 hours after the peak, which means that a risk persists long after the hottest hours."

In 2023, nurses at the Queen Elizabeth Hospital in Birmingham reported in the British Paramedic Journal the first reported cases of contact burns on pavement in the UK. Both cases occurred in urban areas on 19 July 2022, the hottest day on record in the UK. On that day, the maximum temperature exceeded 40°C in several locations across the country. Both patients had significant comorbidities, which may have contributed to the development of heatstroke and subsequent skin lesions.

The first case involves a 66-year-old man with Parkinson's disease, hypertension, type 2 diabetes, and a previous stroke. He was found unconscious while a passenger in a car. On the advice of the emergency room operator, his relatives placed him in the recovery position (right lateral decubitus) on the asphalt pavement of a parking lot. The patient remained on the ground for approximately 15 minutes, until the ambulance arrived.

This prolonged contact with an overheated ground during a heatwave caused burns over approximately 5% of his total body surface area. This patient had second-degree burns to the occipital scalp, right elbow, left elbow and right buttock, a third-degree burn to the right leg (1%) and a deep dermal burn to the right flank (1%).

Some of the burns were deep and required skin grafts nearly a month later. A week after the procedure, complete graft take was observed. The loss of consciousness was attributed to heatstroke, aggravated by his Parkinson's disease.

The second case involved a 58-year-old woman who suffered heatstroke near her home and collapsed on the road during a sweltering heatwave. Surveillance camera footage showed she remained there for approximately 45 minutes before emergency services arrived. She suffered burns to both forearms, both hands, and her left knee, representing approximately 2% of her total body surface area. The wounds were debrided and covered with greasy dressings during her hospital stay. Ten days later, she was readmitted for a thin skin graft. A follow-up four days after the procedure showed complete graft take.

The authors emphasize the need for information, both for healthcare professionals and the general public, to prevent burns from contact with overheated ground. "This is particularly relevant for first aid personnel, who may be required to place a patient in the recovery position on a pavement or roadway. We suggest that pre-hospital teams and first aiders be aware of the risk of burns from contact with the ground in hot conditions and that they take precautions to avoid direct skin contact with this type of surface. This may include, for example, placing the patient in the shade or on a protective surface," emphasize Emma Whiting and her colleagues from Birmingham.

Awareness is also being raised among parents of young children, who may let them play or walk barefoot or without suitable shoes.

Published in 2021, a study conducted by physicians at the Las Vegas School of Medicine in Nevada tracked cases of sidewalk burns occurring between January 2014 and December 2019. The maximum ambient temperature at the time of the injuries was 38.9°C. In three-quarters of cases, it reached 37.2°C. The majority (80%) occurred during the summer (June to August).

This retrospective pediatric study included 45 young patients. Two age groups were clearly distinguished: children 3 years of age or younger (89% of cases) and adolescents 14 years of age or older (11%). Almost all (97%) of bilateral plantar burns occurred in children 3 years of age or younger. All had second-degree burns. One patient also had a third-degree burn. The average body surface area burned was 2.5%.

The main cause was walking barefoot on an overheated pavement (69%), followed by a fall on the pavement (13%), an epileptic seizure (2%), and other causes (16%). Burns most commonly affected the soles of both feet (65%), legs (22%), palms of the hands (4%), and arms (9%).

All burns were treated on an outpatient basis and with local care only, without surgery. The average time to achieve 95% healing was 10 days.

This study found that pavement burns in children are much less severe than in adults. Furthermore, unlike adults, whose burns affect various parts of the body, nearly two-thirds of children suffered burns on the soles of their feet.

These burns mostly affect very young children walking unattended and without proper footwear on the sidewalk. As soon as they feel the pain, they quickly move to a cooler surface or a loved one hears them scream and comes to their aid. These circumstances differ from those encountered in adults, who often suffer burns after prolonged exposure to a hot sidewalk, related to diabetic neuropathy or a physical inability to get up.

Finally, several recent studies indicate that we can expect an increase in the number of burns from contact with hot ground in the coming years. "Due to global warming, we expect an increase in the incidence of extreme heat events, and therefore of pavement burns," concluded the authors of the Birmingham study two years ago.

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