Centipede Bites

Pathogenesis and Venom Action

The Venom Apparatus and Forcipules

• Forcipules: Centipedes do not bite with their mouthparts. Instead, they use their first pair of trunk legs, modified into two sturdy venom claws just beneath the head. Each claw tip has an opening connected directly to a venom gland inside the body.
• Penetration: The claws pierce through the epidermis into the dermis and subcutaneous fat, injecting venom directly into the soft-tissue microcirculation.

Venom Composition and Toxic Effects

• Tissue-digesting enzymes:
  • Metalloproteinases and endopeptidases: Break down collagen, elastin and the basement membrane of small vessels, causing leakage, bruising and necrosis of the tissue under the skin.
  • Hyaluronidase: Degrades hyaluronic acid between cells, acting as a "spreading factor" that helps the venom travel quickly into surrounding tissue.
• Peptide toxins and pain mediators:
  • Peptide neurotoxins (e.g., Ssm Spooky Toxin, SsTx): Block KCNQ potassium channels on nerve cells and vascular smooth muscle, causing vasospasm, disrupted nerve signaling and cell injury.
  • Histamine, serotonin, kinins: Directly stimulate C-fiber and A-delta pain receptors (nociceptors), producing sudden, sharp pain along with marked vasodilation and acute dermal swelling.

Clinical Presentation

Acute Local Skin Reactions

• Paired puncture marks: Two small red hemorrhagic dots close together (0.5–1.5 cm apart) at the center of the lesion, marking where the two claws entered the skin.
• Sudden severe pain: Intense stabbing, burning pain begins immediately after the bite, may spread along the affected limb and can last from a few hours to several days.
• Spreading swelling and redness: The skin around the bite becomes swollen, flushed, hot and tight. The swelling can completely distort a hand, foot or the face.

Blisters and Tissue Necrosis

• After 12–24 hours, clear or blood-filled blisters (hemorrhagic bullae) may form at the center of the bite.
• In severe envenomation by giant centipedes (Scolopendra), the blister can break down into a gray or black necrotic eschar that eventually sloughs off, leaving a deep, slow-healing ulcer.
• Lymphangitis: A red streak tracking along the lymphatic vessels toward the regional lymph nodes (such as those in the armpit or groin).

Systemic Symptoms and Serious Complications

• Although uncommon, bites in children or large bites can cause fever, chills, headache, dizziness, nausea, sweating and generalized lymph node swelling.
• Rare but serious complications: Acute muscle breakdown (rhabdomyolysis), heart muscle injury from coronary vasospasm, secondary acute kidney injury, or systemic hypersensitivity reactions and anaphylaxis.

Emergency Care at Haute-Derma

Step 1: Initial Care and Hot Water Immersion to Inactivate the Venom

• Rationale: Many of the proteins and peptide toxins in centipede venom are heat-labile.
• How to do it: Immerse the bitten limb in warm water right away for 30–45 minutes (or apply warm compresses at a similar temperature where immersion is not possible). This helps denature the protein venom, lowers pressure in the small vessels and brings acute pain down quickly.
• Wound cleansing: Clean the wound thoroughly with saline and povidone-iodine or chlorhexidine.

Step 2: Assessing the Severity of Envenomation

• We check vital signs, screen for systemic allergic reactions and, if rhabdomyolysis is suspected, monitor CK (creatine kinase) and urine myoglobin.

Step 3: Local Sensory Nerve Block

• If warm water does not fully relieve the severe pain, 1% lidocaine (without epinephrine) is injected around the bite or used to block the corresponding peripheral nerve.

Medical Treatment and Recovery Care at Haute-Derma

Topical and Systemic Medical Treatment

• Systemic pain relief: Oral acetaminophen (paracetamol) combined with an NSAID (ibuprofen 400 mg or ketoprofen) for 3–5 days to ease pain and tissue inflammation.
• Oral antihistamines: Levocetirizine (5 mg/day) or fexofenadine (180 mg/day) to relieve itching, dampen hypersensitivity and reduce swelling.
• Topical and oral corticosteroids:
  • A potent topical steroid (clobetasol propionate or betamethasone) applied twice daily for 5–7 days.
  • Oral prednisolone (0.5–1 mg/kg/day for 3 days) when swelling spreads to involve the whole limb.

Preventing Infection and Caring for Necrotic Ulcers

• Tetanus prophylaxis: Vaccination history is checked and tetanus prophylaxis (vaccine and/or tetanus antitoxin) is given to centipede bite patients when indicated.
• Antibiotics to prevent secondary infection: Centipedes live in damp places and carry many gram-negative and anaerobic bacteria. If there is a risk of secondary infection or cellulitis, a broad-spectrum oral antibiotic such as amoxicillin-clavulanate (875/125 mg twice daily) or cephalexin is prescribed for 7 days.
• Blister and necrosis care:
  • Intact blisters are left alone; if a blister is large, tense and painful, the fluid is drained under sterile conditions with a fine needle.
  • Dry necrotic tissue is gently debrided once its borders are clearly defined.

Skin Repair and Scar Prevention

• Once the acute inflammation settles, a repair cream containing madecassoside, epidermal growth factor (EGF), panthenol and hyaluronic acid is applied to speed up regrowth of the epidermis.
• Melanocyte-inhibiting ingredients (niacinamide, azelaic acid) are combined with long-pulse laser or light-based therapy to prevent post-inflammatory hyperpigmentation (PIH) and atrophic scarring where the claws penetrated deeply.