Dr Venom’s pick of Dangerous Spiders & Arachnids you may encounter! Bites, First Aid & Identification by Marbella’s leading Naturalist and Venomous Animals Expert.

The Violin Spider

Figure 1. Adult Female Loxosceles rufescens (Dufour, 1820)

A very dangerous Mediterranean spider, that is as elusive as it is common. Violin Spiders produce virulent cytotoxic venom that can cause severe tissue damage. Overall these delicate spiders are uniform brown with a darker abdomen.

The spider is identified by the distinctive violin shaped marking on its carapace. They have six eyes arranged in three pairs and are nocturnal, preferring to hide in dark corners during the day. They have a leg span of around 30mm although some males may exceed this. They are hunting spiders with good sight but only up to a foot. In the winter time, Violin Spiders do not have to leave their shelter as they have the ability to go without food for up to six months.

Figure 2. Detail of violin marking on carapace.

Region

Violin Spiders range throughout Andalusia, the Mediterranean and North Africa and have also been introduced to North America, Australia and Japan.

Habitat

These spiders live side by side with humans; they can be found in the garage, out buildings and inside your villa - you may even find them behind your bed! They are often found in boxes amongst papers, in the folds of clothing and in bedroom closets. They tend to prefer dry locations that remain undisturbed such as attics and cellars. Outdoors, the spiders are found under rocks or loose bark in relatively dry areas.

Symptoms

Human reactions to the venom can vary from irritation to severe systemic conditions, which in the worst cases, can result in death. A characteristic blister with a red centre follows the bite which often goes unnoticed; it may be several hours before the venom takes effect. Then it is very painful.

The venom of this species can cause damage to the skin, especially around the bitten area known as Necrotising arachnidism syndrome. In serious cases when the victim develops a reaction to the venom, the toxin may cause ulceration of the dermal tissue, which may be slow to heal or in some cases chronic. In extreme cases, additional systemic reactions can occur including paresthesia, convulsions, coma or rarely death.

Figure 3. Violin Spider bite after 3 days to 1month

Violin Spider bite after 3 days to 1month

First Aid

Apply an ice pack and seek medical attention immediately. It is important that the medical team accurately identifies the spider. Take Dr Venom’s Guide to Poisonous Creatures with you and use it for this purpose. The susceptibility of the patient will determine the seriousness of the symptoms and the treatment required.

Medical treatment may include the prompt administration of corticosteroids, topical and oral administration of antihistamines. As well as ulcer healing drugs and creams.

Avoid narcotics (morphine, codeine, etc.) as these can enhance the systemic effects.

Violin Spiders are not aggressive and bite only when forced into contact with human skin, so check those clothes!

Both males and females can bite and inoculate noxious venom.