Dog bite injuries range from minor abrasions to deep, crushing puncture wounds that penetrate soft tissue. The primary concern with any bite that breaks the skin is the high risk of infection, as a dog’s mouth contains a complex mixture of bacteria. Common contaminants like Pasteurella multocida, Staphylococcus, and Streptococcus species are forcibly injected beneath the skin surface during a bite. Quick assessment for signs of complication is necessary because the wound environment is ideal for rapid bacterial growth. Certain symptoms indicate that the body’s natural defenses are being overwhelmed and require immediate medical attention.
Immediate Signs of Localized Infection
A localized infection, often appearing within 24 to 72 hours, is typically the first sign that bacteria are multiplying within the wound site. While some initial pain and swelling are expected as part of the body’s natural inflammatory response, a worsening of these symptoms signals a problem. Look for pain that actively increases after the first day instead of beginning to subside. This intensifying discomfort is a reaction to the pressure caused by the growing bacterial colony and the body’s immune response.
Spreading redness, known as cellulitis, indicates a localized infection extending into the surrounding skin and soft tissue. This redness expands outward from the wound edges and often feels warm to the touch. The area around the bite may also become increasingly swollen and feel hard (indurated), suggesting fluid and inflammatory cells are accumulating beneath the surface.
The presence of purulent discharge (pus) is a clear sign that the body is fighting the invading bacteria. This discharge is a thick, cloudy fluid composed of dead white blood cells, bacteria, and tissue debris. Pus that is yellow, green, or foul-smelling indicates a significant bacterial presence requiring antibiotic treatment. Prompt medical assessment is necessary if these localized signs worsen over time.
Indicators of Deep Tissue Injury
Beyond the risk of infection, a dog bite can cause significant damage to underlying structures due to crushing force. Functional loss symptoms indicate that nerves, tendons, or blood vessels have been compromised. If the bite is on a limb, numbness or persistent tingling distal to the wound suggests peripheral nerve damage. This loss of sensation can be temporary or permanent, depending on the injury’s severity.
Damage to tendons may manifest as weakness or the inability to move a joint normally. For example, a hand bite might prevent a person from fully flexing or extending their fingers. Uncontrolled or pulsing bleeding that does not stop after applying sustained pressure can indicate a laceration to a major blood vessel. These deep injuries require immediate surgical assessment, as they threaten the function and viability of the affected limb.
Systemic Symptoms Requiring Emergency Care
Systemic symptoms occur when the infection progresses beyond the local wound site and affects the entire body, potentially leading to sepsis. A high fever (above 100.4°F or 38°C), along with uncontrolled shivering or chills, suggests the infection has entered the bloodstream. This systemic spread triggers a widespread inflammatory response.
Confusion, disorientation, or extreme fatigue are signs of organ dysfunction related to severe systemic infection. Red streaks extending away from the wound toward the trunk (lymphangitis) indicate that bacteria are traveling through the lymphatic vessels.
Swollen or tender lymph nodes nearest to the bite (armpit or groin) are the body’s filtering stations. A rapid heart rate or unexpectedly low blood pressure can also indicate severe sepsis. Any combination of these symptoms warrants immediate contact with emergency services, as timely intervention with antibiotics is required to prevent organ failure.
Specific Disease Risks Associated with Bites
Two serious infectious diseases that can be transmitted through a dog bite are tetanus and rabies, both requiring specific prophylactic treatment. Tetanus is caused by the bacterium Clostridium tetani, often found in soil and introduced through deep puncture wounds. The disease affects the nervous system, leading to painful muscle contractions, including jaw cramping and generalized muscle stiffness. Maintaining an up-to-date vaccination status is the primary defense; a tetanus booster may be necessary for deep wounds if more than five years have passed since the last dose.
Rabies is a viral disease that attacks the central nervous system and is fatal once clinical symptoms appear. While rare in developed countries due to widespread animal vaccination, exposure is a risk if the biting animal is a stray or has an unknown vaccination history. Initial symptoms can include fever, headache, and an unusual tingling or burning sensation at the bite site. Immediate post-exposure prophylaxis (PEP) is required if rabies exposure is suspected, consisting of a series of vaccinations and, sometimes, rabies immune globulin administered into the wound area to neutralize the virus.