Airbags are lifesaving during motor vehicle accidents (MVAs), but their deployment has been associated with skin issues such as irritant dermatitis1; lacerations2; abrasions3; and thermal, friction, and chemical burns.4-6 Ocular issues such as alkaline chemical keratitis7 and ocular alkali injuries8 also have been described.
Airbag deployment is triggered by rapid deceleration and impact, which ignite a sodium azide cartridge, causing the woven nylon bag to inflate with hydrocarbon gases.8 This leads to release of sodium hydroxide, sodium bicarbonate, and metallic oxides in an aerosolized form. If a tear in the meshwork of the airbag occurs, exposure to an even larger amount of powder containing caustic alkali chemicals can occur.8
We describe a patient who developed a bullous reaction to airbag contents after he was involved in an MVA in which the airbag deployed.
Case Report
A 35-year-old man with a history of type 2 diabetes mellitus and chronic hepatitis B presented to the dermatology clinic for an evaluation of new-onset blisters. The rash occurred 1 day after the patient was involved in an MVA in which he was exposed to the airbag’s contents after it burst. He had been evaluated twice in the emergency department for the skin eruption before being referred to dermatology. He noted the lesions were pruritic and painful. Prior treatments included silver sulfadiazine cream 1% and clobetasol cream 0.05%, though he discontinued using the latter because of burning with application. Physical examination revealed tense vesicles and bullae on an erythematous base on the right lower flank, forearms, and legs, with the exception of the lower right leg where a cast had been from a prior injury (Figure 1).
FIGURE 1. Tense bullae on the legs with sparing of the lower right leg where there is a cast.
Two punch biopsies of the left arm were performed and sent for hematoxylin and eosin staining and direct immunofluorescence to rule out bullous diseases, such as bullous pemphigoid, linear IgA, and bullous lupus. Hematoxylin and eosin staining revealed extensive spongiosis with blister formation and a dense perivascular infiltrate in the superficial and mid dermis composed of lymphocytes with numerous scattered eosinophils (Figures 2 and 3). Direct immunofluorescence studies were negative. Treatment with oral prednisone and oral antihistamines was initiated.
FIGURE 2. Acute epidermal spongiosis with vesicle formation and perivascular lymphohistiocytic inflammation in the superficial to mid dermis with extravasated erythrocytes (H&E, original magnification ×40).
FIGURE 3. Numerous eosinophils admixed with lymphocytes surrounding a dermal blood vessel (H&E, original magnification ×400).
At 10-day follow-up, the patient had a few residual bullae; most lesions were demonstrating various stages of healing (Figure 4). The patient’s cast had been removed, and there were no lesions in this previously covered area. At 6-week follow-up he had continued healing of the bullae and erosions as well as postinflammatory hyperpigmentation (Figure 5).
FIGURE 4. Healing erosions and a few bullae on the legs at 10-day follow-up.
FIGURE 5. Healing erosions and bullae on the posterior aspect of the legs, with sparing on the right due to a cast, at 6-week follow-up.
Comment
With the advent of airbags for safety purposes, these potentially lifesaving devices also have been known to cause injury.9 In 1998, the most commonly reported airbag injuries were ocular injuries.10 Cutaneous manifestations of airbag injury are less well known.11