Tali lesioni spesso guariscono in settimane, ma possono lasciare ampie cicatrici. I sintomi comprendono nausea e vomito , malessere, febbre , anemia emolitica e trombocitopenia. Soltanto un altro genere noto ragno Sicarius e diversi batteri patogeni sono noti per contenere questo enzima. Le vittime del morso possono ritardare la ricerca di cure mediche fino a una settimana. A causa di questo, specie non necrotiche sono spesso erroneamente identificate come ragni eremita marroni.
|Published (Last):||28 October 2014|
|PDF File Size:||20.48 Mb|
|ePub File Size:||18.52 Mb|
|Price:||Free* [*Free Regsitration Required]|
Pathophysiology[ edit ] Loxoscelism may present with local and whole-body symptoms: Necrotic cutaneous loxoscelism is the medical term for the reaction most common in loxoscelism.
It is characterized by a localized necrotic wound at the site of bite. The majority of Loxosceles bites result in minor skin irritation that heals in one week. Viscerocutaneous loxoscelism refers to the combination of local and systemic manifestations that occur infrequently after Loxosceles bites. Symptoms include low energy, nausea and vomiting, and fever. Destruction of blood cells hemolytic anemia may require transfusion and injure the kidney.
DIC may lead to dangerous bleeding. Occasionally, acute kidney failure may develop from myonecrosis and rhabdomyolysis , leading to coma. It is present in all recluse species to varying degrees and not all are equivalent. This toxin is present in only one other known spider genus Sicarius. Thus many bites occur when a spider is trapped in a shirt or pant sleeve.
There is no commercial chemical test to determine if the venom is from a brown recluse. The bite itself is not usually painful. Many necrotic lesions are erroneously attributed to the bite of the brown recluse.
See Note. Skin wounds are common and infections will lead to necrotic wounds, thus many severe skin infections are attributed falsely to the brown recluse. The diagnosis is further complicated by the fact that no attempt is made to positively identify the suspected spider. Because of this, other, non-necrotic species are frequently mistakenly identified as a brown recluse. Physicians wait for the body to heal itself, and assist with cosmetic appearance.
There are, however, some remedies currently being researched. Anti-venoms[ edit ] Anti-venoms are commercially prepared antibodies to toxins in animal bites. They are specific for each bite. There are several anti-venoms commercially available in Brazil, which have been shown to be effective in controlling the spread of necrosis in rabbits.
If too much time is allowed to pass, the treatment becomes ineffective. Most victims do not seek medical attention within the first twelve hours of being bitten, and these anti-venoms are largely ineffective after this point. Because of this, anti-venoms are not being developed more widely. They have, however, been proven to be very effective if administered in a timely manner and could be utilized in Brazil as a legitimate technique.
Surgical treatment[ edit ] In cases where a large dermonecrotic lesion has developed, the dead tissue can be surgically removed. Skin grafting may ultimately be needed to cover this defect. Loxosceles[ edit ] It is suspected that most if not all species of the genus Loxosceles have necrotic venom. Over fifty species have been identified in the genus, but significant research has only been conducted on species living in close proximity to humans.
Loxosceles reclusa Brown Recluse Spider [ edit ] Among the spiders bearing necrotic venom, the Brown Recluse is the most commonly encountered by humans. The range of the brown recluse spider extends from southeastern Nebraska to southernmost Ohio and south into Georgia and most of Texas. It can be distinguished by violin shaped markings on its back. The long spindly "haywire" legs have no spines or banding pattern. The brown recluse has six eyes, arranged in pairs, an uncommon arrangement but not exclusive.
However, many lesser known species of the Loxosceles genus are believed to have similar venoms. For this reason, L. Loxosceles laeta Chilean Recluse Spider [ edit ] Loxosceles laeta , commonly known as the Chilean Recluse Spider, is generally considered to be one of the most toxic species in the Loxosceles genus.
The laeta is cryptozoic, meaning it lives in dark concealed places. This can often mean piles of wood or brick for the laeta, facilitating more transportation of the species into new areas.
Each female can produce up to fifteen egg sacs in its life, with between fifty and one hundred and fifty eggs in each. Loxosceles laeta eggs have a high egg fertility index. Loxosceles deserta Desert recluse [ edit ] L. Human interactions with it are rare, because it usually is only found in native vegetation.
It is not usually found within heavily populated areas, but its range does come near these areas. It is considered medically unimportant due to the low likelihood of human-to-spider encounters. Other species[ edit ] Lampoma cylindrata White-tailed spider [ edit ] The white-tailed spider , found principally in Australia, was formerly blamed for a series of illnesses including necrotic arachnidism. This used to be part of academic and popular belief, but several reviews of the data have dispelled this myth.
It is often encountered by people indoors and outdoors alike. Eratigena agrestis Hobo Spider [ edit ] Many necrotic lesions in the northwestern United States have been attributed to spider bite. The Centers for Disease Control made a survey  as brown recluses are not found in the Pacific Northwest.
However, there is a large population of the E. Critics note that this evidence is only circumstantial. Claims of a medically significant bite should be regarded as a myth. This belief lasted for 50 years until the wolf spider was exonerated.