Spider Bites

Neurotoxic venom
A Neurotoxin is a toxin that specifically acts on nerve cells, normally by interacting with membrane proteins. Most spiders with serious bites have a neurotoxin venom of some sort. The specific style in which the nervous system is attacked varies from spider to spider.
The Widow spiders venom contains latrotoxins, this causes the release of neurotransmitter acetylcholine, that stimulate muscle contractions. This can affect the body in a few different ways such as painful abdominal cramps, interfering with respiration and causing other systemic effects.
The Australasian funnel web spider and the mouse spiders venom works by opening sodium channels, this causes excessive neural activity that interferes with normal bodily functions.
The Brazilian wandering spiders venom is a potent neurotoxin that attacks multiple types of ion channels, there venoms also contains a high level of serotonin that makes a bite from this species very painful.

Necrotic venom
Necrosis is the premature death of cells and living tissue. Necrotic venom is found in the spider family Sicariidae, this includes the recluse spiders and the six eyed sand spiders. Spiders within this family possess a known dermonecrotic agent sphingomyelinase D. Some species with this family are more venomous than others. A bite from a spider in the Sicariidae family can produced symptoms that are minor localized to very bad dermonecrotic lesions, up to severe systemic reactions that include renal failure and in cereous cases, death. With the absence of systemic effects, the bite from a Sicariidae spider can still be serious, by forming a necrotising ulcer, this destroys soft tissue that may take months and sometimes years to heal but leaving a deep scare. Damaged tissue may become gangrenous and eventually fall away. When first bitten, there may be no pain but become painful and itchy in around 2 to 8 hours, with the wound growing in the worst cases to 25cm. Pain and other local effects become worse around 12 to 36 hours after the initial bite, with necrosis developing over a few days.
As the venom spreads throughout the body in minutes, serious systemic effects may occur before this time. More mild symptoms include fever, rashes, nausea, vomiting, muscle and joint pain. More sever symptoms rarely occur that may include

Treatment
The treatment of a spider bite depends on the spider its self, most spider bites are harmless to humans and don't require first aid. If bitten and experience extreme discomfort and require treatment, the spider if seen biting you may need to be identified by an expert, so that they can determine the species of the spider so the proper course of treatment can be administered. The best thing to do is to try and catch the spider, either alive or in a well preserved condition.

A spider that has been flattened or left to decay may not be useful in a definite identification. The majority of medical responders are not trained to identify spiders and very few hospitals have spider experts on there staff. In general it is not possible to identify the type of spider responsible for a bite by observing the symptoms, contrary to media reports.
Unless a spider was seen biting some one, it can not be assumed it was a spider that has coursed any symptoms. Assuming the injury and side effects are from a spider bite can lead to misdiagnosis and mistreatment, leading to potentially life threatening consequences. Spiders are the most common source for false reports. A larger number of spider bites including ones from dangerous species, can be painless and go unnoticed if un observed. Symptoms from more dangerous species bites can manifest hours later, and by this time the spider will be long gone and identification impossible.
Treating a minor bite should be the same for any puncture wound, the wound should be first, encouraged to bleed to wash out any foreign debris. A topical antiseptic should be applied on the chance the bite may have introduced a virus or microbe beneath the skin level, were the antiseptic can penetrate. Observing the bite for a couple of days after is important so that if there are any signs of infection, medical help can be sought after. First aid may involve applying an icepack to control inflammation, applying aloe Vera is a good idea to help soothe the pain, if symptoms are sever, immediate medical care should be sought after.
If bitten by a widow spider, Australian venomous funnel web spider or a Brazilian wandering spider, immediate medical attention should be sought after. In a few cases, bite from these spiders can develop into medical emergency's. Also, medical attention should be sought if there is a severe allergic reaction.

Necrotic bite treatment
Unfortunately there is no established treatment for necrosis. Routine treatments should include immobilization and elevation of the affected limb along with, applying ice, local wound care and tetanus prophylaxis. Other therapies have been tried with varying degrees of success such as hyperbaric oxygen, antihistamines, dapsone, dextran, antibiotics, vasodilators, glucocorticoids, heparin, electric shock, nitroglycerin, curettage, surgical excision and antivenom. All the therapies have not been subject to controlled, randomized trials to conclusively show benefits. Bites are self limited in almost every case and will

Spider Exterminators - Pest Control 
Generally speaking, people do not like spiders and most of all, do not want them in their homes! There are many forms of pest control and ways to exterminate spiders. There are spider exterminators, services, spider zappers, spider traps, spider repeller, spider catchers, spider traps for the removal and extermination process. Advice is available on subjects such as pest controls, pest prevention, spider catchers, spider exterminators and how to kill spiders. Some people would like to eliminate spiders from there homes completely, this can be very difficult as an open window on a summers day will allow spiders in, even opening your front door when entering and leaving will allow pesky spiders in. It is very easy to get rid of spiders by catching them yourself. Its best not to kill spiders as they are very important in controlling the level of other insects that are pests.