Envenomation by the noble false widow spider Steatoda nobilis (Thorell, 1875) – five new cases of steatodism from Ireland and Great Britain

John P. Dunbar, Sam Afoullouss, Ronan Sulpice, Michel M. Dugon

The noble false widow Steatoda nobilis is the only medically significant spider known to occur in the British Isles and Ireland, with a single case of steatodism ever reported from Great Britain. We present here five new cases of envenomations by S. nobilis, three from Ireland and two from Great Britain and describe symptoms not previously reported for the genus Steatoda. Four adult males and one adult female with confirmed S. nobilis bites reported their symptoms to the authors. General practitioner chart was obtained for case #3. In all five cases, envenomations were immediately followed by a sharp and prolonged onset of pain, mild to extensive erythema and localised to extensive swelling around the bite site. Additional symptoms include moderate to intense pruritus, vasodilation of the capillaries around the bite site and a possible minor necrotic wound. In all cases, symptoms subsided within 48-72 h and no further complications were reported. Envenomations by S. nobilis seem to produce symptoms similar (but not identical) to those previously reported from other Steatoda sp. Considering their benign outcome, envenomations by S. nobilis should still be regarded as of moderate medical importance, requiring monitoring and pain management strategies.