Centipedes are predatory arthropods (class Chilopoda) that do not bite using traditional mouthparts like insects or spiders. The injury they inflict is an envenomation delivered by specialized appendages. Centipedes are characterized by their elongated, segmented bodies and use their unique venom apparatus for defense and subduing prey. This article explains the mechanics of venom delivery, common reactions to the toxins, and appropriate steps for immediate care.
Understanding the Venom Delivery System
The mechanism centipedes use to deliver venom is a sting or puncture from a pair of modified front legs called forcipules (toxicognaths). These pincer-like structures are located behind the head and function like fangs to grasp the victim. The forcipules contain a venom gland that runs through a duct to a sharp, hollow point, allowing for venom injection upon piercing the skin.
The injury often presents as two distinct puncture marks arranged in a V-shape. Centipede venom is a complex mixture of biologically active compounds, including enzymes, proteins, histamine, and serotonin. The amount of venom delivered relates directly to the centipede’s size, which influences pain and symptom severity. Larger species, such as tropical centipedes, have longer forcipules capable of penetrating deeper skin layers and injecting a greater volume of venom.
Common Symptoms and Pain Severity
The most immediate reaction to centipede envenomation is intense, localized pain at the puncture site. Victims often describe the sensation as an immediate, severe burning that can range in duration from minutes to several days. This initial pain is quickly followed by local symptoms such as redness (erythema) and swelling (edema) around the affected area. Localized discomfort may also include itching, tenderness, and a tingling or “pins and needles” feeling (paresthesia).
While most reactions remain confined to the injury site, larger species can cause pain comparable to a bee or wasp sting, often lasting up to 48 hours. In some cases, nearby lymph nodes may become temporarily enlarged. Systemic reactions are far less common but can occur in people with heightened sensitivity or allergies to the venom. These rare, widespread symptoms can include headache, nausea, fever, or rapid heart rate.
Immediate Treatment and Medical Guidance
For an uncomplicated centipede envenomation, the initial focus is on wound hygiene and symptom relief. Thoroughly wash the puncture site with soap and water to minimize infection risk. Applying a cold compress or ice pack wrapped in a cloth helps reduce pain and swelling by constricting blood vessels. Over-the-counter pain relievers, such as acetaminophen or NSAIDs, can manage localized discomfort.
Topical antibiotic ointment and a bandage can be applied to protect the skin and promote healing. Patients may find relief from itching and inflammation using oral antihistamines or topical corticosteroids. Professional medical attention is advised if systemic symptoms develop, such as persistent fever, vomiting, or signs of an allergic reaction. Signs of a serious allergic response (anaphylaxis), including difficulty breathing, throat swelling, or widespread hives, require immediate emergency care. Consult a medical professional if localized symptoms worsen after 48 hours or if signs of a secondary bacterial infection, such as red streaks or a foul odor, appear.