It is possible to be bitten by a snake and not realize it immediately. Some snake bites are painless or cause only mild symptoms initially. Venomous snakes like rattlesnakes, copperheads, and cottonmouths/water moccasins have fangs and venom that is used to immobilize and digest prey. Their venom contains complex proteins, enzymes, and other substances that have various effects on the human body.
Some people may be bitten but not feel pain or see fang marks for various reasons:
- The bite may occur in an area with little sensation such as the ankle or foot.
- Only a small amount of venom is injected or the snake fails to release venom (known as a “dry bite”).
- The person is distracted and does not immediately notice the bite.
- Venom proteins act at the bite site and systemically, so local effects are not always apparent immediately.
However, most venomous snake bites do cause fairly rapid symptoms including severe pain, swelling, bruising, and puncture wounds. Lack of any of these signs within 30 minutes makes envenomation unlikely. Still, it is wise to watch for other delayed symptoms of venom poisoning which can develop hours later.
Signs and Symptoms of Snake Bites
Here are some common signs and symptoms of venomous snake bites:
- Instant pain – Severe burning pain at the bite site develops immediately as venom proteins attack tissue and nerves.
- Swelling – Rapid swelling spreads from the bite area over minutes to hours as venom proteins increase local bleeding.
- Bruising – The bite site reddens and turns dark purple due to damaged blood vessels.
- Puncture wounds – Fang marks are visible on the skin, though they may be obscured as swelling increases.
- Nausea and vomiting – These effects arise minutes to hours after being bitten as venom spreads.
- Excessive sweating – Profuse sweating is an early sign of shock due to venom effects.
- Lightheadedness – Low blood pressure from venom makes people feel faint.
- Bleeding – Bleeding from the bite site, gums, and other areas may occur if venom reduces clotting.
- Numbness – Numbness and tingling around the bite result from venom’s effects on nerves.
- Weakness – Generalized weakness develops as venom impairs muscle contractions.
- Blurry vision – Venom can cause low blood pressure and nerve damage leading to vision changes.
However, the severity and time course of symptoms varies based on the snake species, the amount of venom injected, the location of the bite, and the person’s health profile. Bites by snakes like rattlesnakes often cause immediate, intense pain and swelling. But bites by snakes like copperheads may only cause mild symptoms initially that get worse over hours.
Dry Bites
Dry bites occur when a venomous snake bites but does not release venom. Between 20-25% of venomous snake bites are dry bites. Reasons for dry bites include:
- The snake recently bit another victim and its venom glands need time to replenish.
- The bite was warning or defensive, not an attempt to secure prey.
- Younger snakes may not fully control venom release.
- The fangs failed to penetrate adequately for venom injection.
- Stress or fear may inhibit the snake’s control over venom release.
Though dry bites do not inject much venom, they still cause some signs like:
- Mild pain due to the puncture wounds
- Minimal swelling at the bite site
- Tiny bruises from damaged capillaries
- Possible slight numbness from nerve effects
However, systemic effects of envenomation are absent after dry bites. The lack of severe pain, major swelling, bruising, bleeding, or other symptoms within 30 minutes indicates a bite is likely dry. Still, medical evaluation is recommended after any venomous snake bite to be safe.
Delayed Symptoms of Snake Bites
While most snake bite symptoms start quickly, some develop hours later as venom spreads through tissues or starts breaking down proteins, blood cells, and nerves. Delayed signs and symptoms include:
| Time after Bite | Delayed Symptoms |
|---|---|
| 1-2 hours | Nausea, vomiting, diarrhea |
| 2-8 hours | Bruising, bleeding, low blood pressure |
| 8-24 hours | Altered mental status, seizures |
| 24+ hours | Kidney failure, coma, paralysis |
Minor symptoms can progress to systemic, life-threatening complications like bleeding disorders, cardiovascular collapse, paralysis, respiratory failure, and multi-organ damage. People may feel fine for a few hours before severe envenomation emerges. Seeking prompt hospital treatment is crucial even if initial bite signs seem mild or absent.
Conclusion
It is possible for snake bite signs to be missed or develop later after envenomation. However, most venomous snake bites will cause intense, immediate pain and rapid swelling. Lack of these cardinal signs within 30 minutes indicates a bite is less dangerous. Still, you should carefully monitor for delayed symptoms and get medical care after any suspected venomous snake bite just to be safe. With prompt antivenom treatment, serious snake envenomations can usually be cured.