White-tailed Spider

White-tailed Spiders are fund throughout Australia and wrongfully been accused of causing necrotic lesions on the skin. We now how evidence that this is not the case and a painful bite with red mark is the typical presentation.

Resus

• Not required

Risk Assessment

Typical symptoms include:

• A painful bite with a red mark – can last up to 12 days
• Non-specific features of envenoming can include nausea, vomiting, headache and malaise
• Delayed pruritus occurs in 20%

Supportive Care

• Reassure the patient, apply an ice pack and give simple analgesia. A hospital admission is not required.

Investigations

• Only required to establish an alternative diagnosis, this might include swabs or skin biopsies.

Differential Diagnosis:

• If a necrotic cutaneous lesion is present then the following other differentials need to be considered:
• Infections (staphylococcal, streptococcal, herpes simplex, herpes zoster, gonococcal, mycobacterial, fungal)
• Pyoderma gengrenosum
• Squamous cell carcinoma
• Erythema nodosum
• Chemical burn
• Lymphomatous papulosis
• Localised vasculitis
• Factitious injury
• Traumatic

Antivenom

• None available

Disposition

• Patients can all be discharged with appropriate follow-up by a primary care provider, particularly if a necrotic lesion is present.

References and Additional Resources:

Additional Resources:

• Chris Nickson – Spiders and Stingers – SMACC podcast

References:

• Isbister GK, Gray MR. White-tailed spider bite: a prospective series of 130 definite bites by the Lampona species. Medical Journal of Australia 2003; 179:199-202
• Swanson DL, Vetter RS. Bites of the brown recluse spiders and suspected necrotic arachnids. New England Journal of Medicine 2005; 352:700-707