Almost all spiders produce poison. However, the spider bite often cannot penetrate the human skin because most spiders have teeth that are too small and are therefore harmless.
Spider bites can cause mild itching for a few hours, but sometimes they can be dangerous.
Some species that cause dangerous reactions in humans include:
- The black widow, she is between 8 and 40 mm tall. Its color is black, but it has a red spot in the shape of an hourglass on its belly;
- The brown spider (also known as violin spider or brown recluse spider) is 6 to 20 mm in size, brown in color, and has a small darker violin-shaped spot on its abdomen.
These spiders can cause serious reactions that require surgical skin grafting or even amputation.
Contents
Bite of the brown recluse spider or violin spider
The violin spider can be recognized by the small violin-shaped spot on its back. This spider rests during the day and is not aggressive, but will attack if disturbed.
Usually, individuals are bitten only when there is a spider in their clothes or shoes.
Most violin spider bites do not cause any symptoms.
Disease caused by Loxosceles is a disorder caused by the bite of the brown recluse spider.
Usually the bite is painless, but later a lesion develops with:
- Inflammation
- Bleeding
- Pain (1).
Necrosis (cell death) spreads a few days after the bite and leads to necrotic dermatitis, the surrounding skin becomes:
- red (erythema),
- white (ischemia),
- Blue (necrosis).
The venom of this spider contains the enzymes of hyaluronidases and sphingomyelinase D and causes necrosis.
In addition, the activity of neutrophil white blood cells and platelets aggravates cell death.
Symptoms at the site of the bite include:
- Swelling
- Inflammation
- Bleeding
- damage to the walls of the vessels,
- Thrombosis
- Necrosis.
In addition, systemic symptoms may occur, including:
- Acute renal failure,
- rhabdomyelosis (muscle lesions),
- Hemolysis within the vascular system (2).
In some cases, blood clotting disorders can lead to a stroke.
Bite of the hobo spider
The hobo spider is brown with gray spots on the body.
Even after a slight disturbance, she behaves aggressively.
The symptoms caused by its bite are similar to those of the violin spider, but:
- Necrosis is rare,
- As a rule, a permanent scar forms at the site of the bite (3).
Causes of necrosis can be:
- hemolytic properties (destruction of red blood cells) of the poison,
- Transmission of bacteria through the bite site.
Systemic symptoms of the bite may include:
- Headache
- anaphylaxis (severe allergic reaction),
- Death.
The treatment is similar to that of the brown spider.
In addition, surgical removal of the tissue should not be carried out before the completion of the necrosis process, that is, as long as the lesion continues to increase.
Bite of the Black Widow
The Black Widow has a black hairless body.
The males are smaller than the females.
The most important feature of their appearance is a red spot on the abdomen, resembling an hourglass.
In a normal environment, it is not aggressive, but it attacks when provoked, mainly to protect its eggs.
It is also the most poisonous spider:
- In North America,
- In Australia.
Their poison is alpha-latrotoxin (neurotoxic), which stimulates and provokes the release of neurotransmitters in the neurons of the parasympathetic nervous system, leading to the release of:
- catecholamines,
- Acetylcholine.
The symptoms caused by the bite of this spider are called latrodectism. The pain from the bite resembles a pinprick.
The lesion may resemble a target in the vicinity of the bite.
Latrodecism begins after a few minutes with the development of pain throughout the body, and within a few hours symptoms appear such as:
- Vomit
- respiratory insufficiency,
- state of confusion,
- Partial paralysis of the limbs,
- abdominal cramps,
- Hypertension
- Fever
- Fasciculation (muscle contractions that do not result in movement)
- Muscle spasms.
Symptoms can be confused with an acute abdomen (very severe abdominal pain).
As a rule, the black widow bites during the hot months. Rarely, a visible sign remains on the skin, but in 25% of cases, the following are formed:
- An erythema,
- Sweats
- Raised hair.
The diagnosis is made from the patient’s medical report.
Rarely, the bite is fatal, mortality after a bite is less than 1%.
Bite of the tarantula
The tarantula has a brown or black hairy body.
The size can be 7-8 cm.
This species of spider is also kept as a pet.
Their poison is not dangerous to humans and, in addition to fever, provokes only asymptomatic injuries.
The tarantula protects itself by stinging hairs on its body (2).
If these hairs get into the eye, it can lead to inflammation.
With inflammation of the iris, the doctor may recommend:
- eye washes,
- Applying local corticosteroids.
Bite of Phoneutria nigriventer (banana spider)
These spiders have long legs.
Since they often hide in banana boxes, they are known as banana spiders.
The symptom after the bite is a sharp pain (in 96% of patients).
The bite of this spider can lead to respiratory failure and death:
- In infants,
- In children,
- In the elderly.
Their poison is neurotoxic and irritates the autonomic nervous system, causing the following:
- Tachycardia
- Hypertension
- Heavy salivation,
- priapism (painful penile erection),
- Vertigo
- Visual impairment.
There is an antidote for treatment for patients, but it is rarely used.
Symptoms of spider bite
The most common symptoms of spider bites are:
- Itch
- Swelling
- Reddening
- Ache
Signs of deterioration or spread of the poison are:
- blistering on the surrounding skin,
- Feeling of numbness and tingling.
Some symptoms of the spider bite can spread to other areas of the body.
If the person has the following symptoms, he should go to the doctor:
- Leg cramps
- Stomach cramps
- Headache
- Excessive sweating
- Ague
- Fatigue
- Muscle pain and general joint pain
- Accelerated heartbeat.
Weakness could be one of the symptoms after spider bite, so treatment is important.
The spider species can only be detected in a few cases by the injected poison.
Symptoms of the bite of the violin spider
The brown hermit spider is the most dangerous and can be recognized by its venom.
Initially, the spider bite does not cause pain, but after about an hour, symptoms appear in the bite area, including:
- Intense pain,
- Itching, which can also be diffuse.
- A blister surrounded by reddened skin,
- Ulcer; the blister enlarges, bursts and forms an ulcer on the skin.
The bite of the violin spider causes severe local discomfort, rarely systemic symptoms may occur, such as:
- Nausea
- Vomit
- Sweats
- Ague.
Symptoms of the bite of the black widow
The bite of the black widow causes the strongest symptoms, which consist in:
- numbness in the affected area,
- cramps and muscle rigidity (chest, abdomen and shoulders),
- Serious breathing disorders.
In the most severe cases, an antidote is required, otherwise the poison will spread further.
What should you do? Therapy for spider bite
One should consult a doctor if the symptoms:
- begin to affect a wider area,
- last longer than 24 hours.
If the bitten person has not received a tetanus vaccination recently, he should immediately consult a doctor.
It is difficult to predict the severity of the spider bite, because it is not so easy to recognize the type of spider responsible.
Emergency care for the spider bite consists in:
- wound cleansing,
- laying on ice,
If the spider has bitten into a limb (legs or arms), it is recommended to elevate the limb.
Treatment for the bite of the violin spider
All bites must be cleaned.
Patients who develop systemic symptoms must be hospitalized.
The antidote reduces the extent of the necrotic area.
The earlier the antidote is administered, the lower the effects.
Studies show that it is beneficial when administered in the first 4 hours after the bite, but according to another study, it still worked after 12 hours (5). The necrosis triggered by the bite spreads in a few days and ends after a few weeks.
Surgical removal of the skin lesions is indicated only in the case of stable injuries (which do not spread further).
Corticosteroids are indicated for:
- bites leading to severe skin lesions,
- Loxosceles disease,
- Small children.
The antibiotic Dapsone should only be used in adult patients with necrosis who are also glucose-6-phosphate deficient.
The local nitroglycerin may be helpful in blocking the spread of necrotizing ulcers.
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