History
Bites
Unprovoked bites are uncommon because tarantulas are usually docile; patients usually are able to tell what has inflicted their injury.
Most patients bitten by tarantulas complain of mild pain similar to a pinprick. Some tarantula bites can cause severe pain, local swelling, and numbness.
Some patients have reported arthritic stiffness lasting for weeks following bites near joints. No permanent deficits have been reported.
Skin
Symptoms at the site of hair penetration include irritation, severe pruritus, edema, and erythema.
Rarely, anaphylaxis may follow such exposure.
Eye
Ocular exposure to tarantula hairs may lead to redness and an itchy or gritty sensation.
A careful history may be necessary to identify this cause of ocular symptoms because patients may not relate the symptoms directly to tarantula exposure. [7]
Respiratory
Significant allergic rhinitis may be present in patients who have inhaled hairs.
Physical Examination
The findings following a tarantula bite closely resemble those of Hymenoptera stings (ie, local swelling and erythema). As noted above, the exception is the bite of the funnel web spider, which is found outside the United States.
Skin
Like insect bites, tarantula bites cause local erythema and edema.
Erythema and pruritic papules may be observed in skin exposed to urticating abdominal hairs. This exposure also may lead to an allergic reaction and, rarely, precipitates anaphylaxis.
The risk of serious reactions is much higher outside the United States, where spiders with type III and type IV hairs are found.
Eye
Several cases of ocular injuries from discharged hairs have been described in the literature. [8, 9, 10, 11, 12, 13]
Patients may have a red eye [14] and associated keratoconjunctivitis. Depending on the depth of hair penetration, patients also may have conjunctival injection or anterior chamber inflammation.
Ophthalmia nodosa has been diagnosed in several individuals with resulting panuveitis that still was clinically active up to 72 months following the initial diagnosis. [8, 12]
Multiple fine intracorneal hairs may be observed on slit-lamp examination; however, they may be elusive because of their small size and location.
The right eye is affected more commonly than the left eye in patients who are right-hand dominant and handle tarantulas.
Respiratory
Allergic rhinitis signs and symptoms may be present if a patient has inhaled urticating hairs.
Complications
Ophthalmia nodosa and panuveitis can complicate ocular exposure to tarantula hairs.
-
The Chilean rose tarantula. The urticating hairs are clearly visible. Courtesy of Mike Dembinsky.
-
Enlargement of tarantula hairs. Courtesy of Cara Shillington.
-
Slit-lamp photograph showing 2 central infiltrates caused by urticating tarantula hairs (arrows). Courtesy of Southern Medical Journal and David A. Belyea, MD.
