What’s Eating You? Noble False Widow Spider (Steatoda nobilis)
Noble false widow spider (Steatoda nobilis) bites have been documented to cause symptoms ranging from pain and pruritus to systemic bacterial infection resulting in death. This species is found in a broad range of environments, often alongside human activity, and the spiders most often bite defensively when disturbed or when the body is compressed. Due to the rapid expansion of noble false widow spiders and their relatively recent emergence in the United States, it is important for dermatologists to be aware of how to manage their bites.
PRACTICE POINTS
- With evidence of a recent population boom of noble false widow spiders in Europe and spread to California, dermatologists should be aware of these spiders and their bites.
- Symptoms of Steatoda bites (steatodism) include immediate pain followed by intense pruritus, swelling, erythema, and possibly systemic symptoms such as fever. Secondary infections such as cellulitis and septicemia are risks.
- The envenomation site should be kept clean to prevent secondary infection, and medical care should be sought when there is evidence of ulceration or cellulitis.
There are reports of secondary infection after bites and even cases of limb amputation, septicemia, and death.14,17 However, it is unknown if noble false widow spiders are vectors for bacteria transmitted during envenomation, and infection likely is secondary to scratching or inadequate wound care.18,19 Potentially pathogenic bacteria have been isolated from the body surfaces of the noble false widow spider, including Pseudomonas putida, Staphylococcus capitis, and Staphylococcus epidermidis.20 Fortunately, most captured cases (ie, events in which the biting arachnid was properly identified) report symptoms ranging from mild to moderate in severity without the need for hospitalization. A series of 24 reports revealed that all individuals experienced sharp pain upon the initial bite followed by erythema, and 18 of them experienced considerable swelling of the area soon thereafter. One individual experienced temporary paralysis of the affected limb, and 3 individuals experienced hypotension or hypertension in addition to fever, skin necrosis, or cellulitis.14
Treatment
The envenomation site should be washed with antibacterial soap and warm water and should be kept clean to prevent infection. There is no evidence that tight pressure bandaging of these bite sites will restrict venom flow; because it may worsen pain in the area, pressure bandaging is not recommended. When possible, the arachnid should be collected for identification. Supportive care is warranted for symptoms of pain, erythema, and swelling, with the use of cool compresses, oral pain relievers (eg, nonsteroidal anti-inflammatory drugs, acetaminophen), topical anesthetic (eg, lidocaine), or antihistamines as needed.
Urgent care is warranted for patients who experience severe symptoms of steatodism such as hypertension, lymphadenopathy, paresthesia, or limb paralysis. Limited reports show onset of this distress typically within an hour of envenomation. Treatments analogous to those for latrodectism including muscle relaxers and pain medications have demonstrated rapid attenuation of symptoms upon intramuscular administration of antivenom made from Latrodectus species.21-23
Signs of infection warrant bacterial culture with antibiotic susceptibilities to ensure adequate treatment.20 Infections from spider bites can present a few days to a week following envenomation. Symptoms may include spreading redness or an enlarging wound site, pus formation, worsening or unrelenting pain after 24 hours, fevers, flulike symptoms, and muscle cramps.
