Cobra Envenomation Clinical Presentation

Updated: Jun 15, 2018
  • Author: Robert L Norris, MD; Chief Editor: Joe Alcock, MD, MS  more...
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The onset of symptoms and signs following a cobra bite can be extremely variable, as follows:

  • Immediate, local pain (almost always present)

  • Soft tissue swelling (may be progressive)

  • Neurologic findings, which may begin early and be rapidly progressive (in anecdotal cases, victims have suffered respiratory arrest in a matter of minutes) or may be delayed in onset as long as 24 hours

  • Alteration of mental status (eg, drowsiness, occasionally with euphoria)

  • Complaints related to cranial nerve dysfunction, such as ptosis (often one of the earliest neurotoxic findings), ophthalmoplegia, dysphagia, and dysphasia

  • Profuse salivation, nausea, vomiting, and abdominal pain

  • Paresis of neck and jaw muscles and generalized muscular weakness followed by flaccid paralysis

  • Shortness of breath, respiratory failure (muscular paresis and accumulated secretions)

  • Chest pain or tightness

  • Eye pain, tearing, blurred vision (with eye exposure to venom from spitting cobras)


Physical Examination

Impending respiratory failure may be heralded by respiratory distress or weakness and cyanosis.

Neurologic dysfunction may be heralded by altered mental status, ptosis (may be the earliest sign of systemic toxicity), and/or generalized weakness or paralysis.

Cardiovascular collapse may be heralded by hypotension and/or tachycardia or bradycardia.

Soft tissue edema may be noted.

Signs of necrosis usually appear within 48 hours of the bite. The area around the fang punctures darkens.

See the image below.

Necrosis from a Naja atra (Chinese cobra) bite. Th Necrosis from a Naja atra (Chinese cobra) bite. This resulted in a severe deformity. The patient had few systemic signs or symptoms. Photo by Sherman Minton, MD.

Blistering may follow.

Necrosis is usually confined to the skin and subcutaneous tissue but may be quite extensive. See the image below.

Necrosis from a cobra bite. Photo by Sherman Minto Necrosis from a cobra bite. Photo by Sherman Minton, MD.

A putrid smell is characteristic.

Acute inflammation of the eye follows venom-spitting exposure and is characterized by ocular congestion, edema of the conjunctiva and cornea, and a whitish discharge.



Complications of cobra envenomation may include the following:

  • Respiratory failure/arrest

  • Cardiovascular collapse

  • Prolonged neuromuscular weakness

  • Tissue necrosis

  • Antivenom-related complications - Nonallergic anaphylactic (anaphylactoid) reactions, delayed serum sickness
  • Venom-induced ophthalmia (spitting cobras)