Tarantula Envenomation Treatment & Management

Updated: Jun 19, 2020
  • Author: Scott D Fell, DO; Chief Editor: Joe Alcock, MD, MS  more...
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Treatment

Prehospital Care

Capture the offending arachnid for identification if it is possible to do so safely.

Begin supportive therapy for patients who are having a rare allergic reaction or anaphylaxis.

Following ocular exposure, place a protective shield over the eyes to prevent the patient from rubbing the eyes and possibly driving hairs deeper.

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Emergency Department Care

A patient with anaphylaxis or allergic reaction requires prompt supportive care and attention to the ABCs.

In patients with severe reaction, establish an intravenous line, provide supplemental oxygen, and place them on a cardiac monitor.

Skin

Protect areas of localized dermatitis and allergic reactions with appropriate local wound care, including wound cleansing and ice to decrease inflammation.

Determine tetanus immunization status and provide prophylaxis as needed.

Treat pruritus and erythema with antihistamines and corticosteroids.

Administer parenteral or enteral analgesics to relieve severe pain.

Eye

Ocular injury caused by tarantula hairs can be complicated and requires ophthalmologic consultation.

After initial evaluation, patients should be treated with a topical broad-spectrum antibiotic.

Topical steroids are required for patients with panuveitis or keratoconjunctivitis; they should be prescribed only after consultation with an ophthalmologist.

As with skin contact, tetanus prophylaxis is indicated when the eye is involved.

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Medical Care

Patients with local dermatitis caused by urticating hairs should be discharged from the ED with a course of oral corticosteroids (eg, prednisone) and an antihistamine such as cetirizine (Zyrtec) or diphenhydramine (Benadryl).

Cetirizine may be preferred because of its lower incidence of anticholinergic adverse effects and the convenience of once-a-day dosing. The drawback of cetirizine is its higher cost.

A prescription for oral analgesics also should be provided.

Local skin wounds from tarantula bites or urticating hairs should be re-examined in 48 hours; patients should be educated regarding the signs and symptoms of infection.

Patients with ocular involvement should be seen by an ophthalmologist as soon as possible (< 24 h).

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Consultations

Patients can develop long-term inflammatory changes in the eye exposed to tarantula hairs, and definitive diagnosis of retained hairs cannot always be made by routine ED slit-lamp examination. Consulting an ophthalmologist is mandatory in such exposures.

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Prevention

Tarantula bites can be avoided almost completely by not attempting to handle or harass these arachnids. Wearing gloves when gardening and being cautious about hand placement can prevent accidental bites.

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