ANNUAL PUBLIC HEALTH ISSUE: If It Wasn't A Spider Bite, What Was It?

In my experience, the general public and the medical community are quick to determine that all kinds of dermatological eruptions are the result of spider bites when there is no proof whatsoever that a spider was involved in the incident. This unsubstantiated finger pointing has gone on for so many decades that baseless speculation has become “gospel truth” due to lack of dissenting voices. In addition, arachnophobia (the fear of spiders) fuels the fire because spiders are generally feared, loathed, despised and otherwise considered to be nocturnal ne’er-do-wells, prowling bedrooms at night, inflicting their venomous malevolence. However, when you start to actually look for hard evidence in these situations, many alleged anthro-arachno-interactions have no basis in truth.

Many medical conditions are buried under the ubiquitous diagnosis of “spider bite” yet have nothing to do with spiders. Although routine medical care will probably be sufficient to remedy most “spider bites” no matter what their real cause, some conditions that are mistaken for envenomations require specific and much more aggressive therapy. Several of these more serious cases are misdiagnosed as brown recluse bites. Although the brown recluse can be a source of significant morbidity in the South and central Midwest states, the hyperbole and infamy surrounding this spider causes it to be blamed for an amazing number of conditions that have nothing to do with venom. This is apparent from the fact that although brown recluses are rarely found outside their endemic area, “brown recluse bite diagnoses” occur throughout the continental United States, even in states where the spider has never been documented.

What is presented here is a discourse on the multitude of conditions that can cause necrotic (or rotting flesh) wounds that can be mistaken for a brown recluse bite or that medical professionals have misdiagnosed as such. Although this article will have the greatest utility in areas of the United States where brown recluses don’t exist, it does also pertain to endemic recluse areas as well. Brown recluses aren’t the only things that cause necrotic wounds; Other conditions should also be given credence when determining the causes of skin lesions.

A problem in non-endemic recluse territory is that often a doctor will diagnose a brown recluse bite in a person who then requests pest control of a spider that is non-existent in that area. Explaining the lack of local recluse populations to the client is met with skepticism because the client often believes that the doctor knows more about the local spider fauna than the PCO who deals with spiders every week in the course of the profession.

What I hope to do here is present sufficient information to educate PCOs such that they will be able to supply more answers to their customers when informing them when there are no brown recluses in their home needing to be controlled. Typically in non-endemic areas, when you shatter the skeptical homeowner’s dearly held misconceptions, they will say, “Well, if it isn’t a recluse bite, what is it?” The problem is that “brown recluse bite” is the only thing that they have ever heard of that causes necrosis.

I have found that if you can give the skeptic a laundry list of other conditions that have been mistaken for recluse and spider bites, they start to lower their hackles, start to listen and maybe, just maybe, start to realize that their doctor may not know much more about spiders than they do themselves.

However, it is important to remember that the pest management professional is not a doctor and only a doctor can make medical diagnoses.

Bacteria infections. This is probably one of the biggest causes of dermatological eruptions on the body. Any time there is a puncture of the skin, there is a chance of bacteria infection. One of the most common symptoms of an arthropod bite or sting is itchiness. Then what does the person do?

Scratches. If the skin is broken, a secondary bacterial infection can occur. The wound was initiated by an arthropod but it is not the result of venom or salivary glands. It is the grubby fingernails that do the damage.

This is one of the biggest problems with real brown recluse bites, which are notoriously free of bacteria for the first few days but then get infected when the itching causes the patient to scratch. Of course, the ensuing wound is blamed completely on the spider’s venom, which is incorrect.

Variants of Staphylococcus and Streptococcus bacteria are probably most often responsible for the wounds. These include multi-resistant Staphylococcus aureus and necrotizing bacteria, the latter of which can be fatal in some cases. Impetigo is a bacterial infection that is contagious and has been misdiagnosed as a recluse bite. Finally, you may have read about the 7-month-old child in New York who contracted cutaneous anthrax in the bioterrorism events of Autumn 2001. The child’s anthrax was initially diagnosed as a recluse bite even though only one brown recluse has ever been listed as being found in New York state.

Viral and fungal infections. Various forms of herpes (chronic herpes simplex, infected herpes simplex, herpes zoster) have been misidentified as brown recluse bites. These are caused by viruses.

Sporotrichosis is a fungal infection inoculated from plant material via a break in the skin and it sometimes leaves a skin lesion. This fungus can be found on rose thorns, pine seedlings, hay, sphagnum moss, etc., and infections are occupational hazards for gardeners and landscapers. The wounds are usually found on the backs of the hands and the forearms and there are outbreaks after Arbor Day celebrations. If someone tells you that they received a brown recluse bite while gardening (recluses are not found in vegetation), sporotrichosis is a likely candidate.

Ticks and Lyme disease. One misdiagnosis with severe consequences is that Lyme disease sometimes can exhibit a bull’s eye rash or a necrotic lesion, which are characteristic symptoms of brown recluse bite. Missing a diagnosis here can be tragic because if Lyme disease is not detected early enough, it can lead to irreversible heart and nerve damage and even death. Lyme disease is also similar to brown recluse bites in that its predictability is geographically limited to the distribution of the arthropods, discounting travelers. For example, a New Englander vacationing in Connecticut was diagnosed with brown recluse bite by his Rhode Island doctor. He realized from distribution maps that it was unlikely to be a recluse and pursued the Lyme disease angle, which is what it eventually turned out to be.

Bites of other ticks can leave wounds that can be mistaken for spider or recluse bites including a soft tick, Ornithodoros coriaceus. One medical report even states that Rocky Mountain spotted fever was even mistaken for recluse bite.

Other arthropods. It is amazing that often these wounds are blamed on the accidental, defensive bite of a spider rather than considering the multitude of blood-feeding arthropods that surreptitiously seek out mammals for bloodmeals. Fleas, mites, ticks, bedbugs and kissing bugs all can leave evidence of their dinnertime and punctures of skin are susceptible to infection or reaction to salivary fluids. One of the problems with blaming spiders is that the homeowner starts a spider-smashing campaign and continues to overlook the actual cause of the wounds, which may continue unabated (with the PCO taking the blame for failure to kill the offending, unseen “spiders” doing the biting).

Topical contaminants. Poison ivy and poison oak have been mistaken for recluse bites when there is only one eruption because usually when you have contact dermatitis from these plants, it is widespread over parts of the body.

A northern Californian man was diagnosed as having a recluse bite but through good detective work, he was able to determine that the cause of the wound was actually a chemical burn from oven cleaner that he knelt in. Considering how common caustic household products are in the home and how easily they can be incorrectly used, there are probably many cases of burns that are explained away as spider or recluse bites.

Lymphoproliferative diseases. Some cancers (lymphoma) and cancer-like diseases (lymphomatoid papulosis) can leave lesions that are mistaken for spider and recluse bites. A physician in British Columbia diagnosed a wound on a woman’s back as brown recluse bite and even identified a spider from her house as a brown recluse (which unfortunately was tossed out before it could be correctly identified by an arachnologist). The woman sought another medical opinion after a local arachnologist told her that no brown recluses have ever been found in her area; her “bite” turned out to be cutaneous lymphoma.

I just completed a study on 106 patients who have lymphomatoid papulosis, a rare, non-fatal disease. Of these 106 people, 16 of them were initially told that they had spider bites for their lymphoproliferative condition, five of the 16 were told they had brown recluse bites and four of these five sufferers came from areas of the country that do not have brown recluses. One of these four had their “brown recluse bite” surgically removed to prevent “venom spread.”

Underlying physiological diseases. Pyoderma gangrenosum is a nasty, painful condition that is associated with digestive diseases and causes large necrotic wounds on the flesh, usually on the legs and feet but can be elsewhere on the body. The condition typically lies in wait, until something like a knife cut, skinned shin or even a spider bite unleashes a cascade of events.

A diabetic ulcer is another condition that sometimes can lead to a necrotic skin wound because of circulation problems.

Blood disorders. Anytime there is clotting inside the body on a microscopic level, there is a chance for loss of blood flow to tissue, hence the cells die and can leave a necrotic wound on the skin. This clotting could be due to a disease inside the body or a strange reaction to drugs that alter the clotting function of the body amongst other situations.

Miscellaneous. There are several other conditions that can cause rotting flesh wounds. Some of these conditions have no known cause or can be something as simple as a bed sore.

CONCLUSION. What should be apparent is that nothing is very simple when one starts to look at “spider bites” and “brown recluse bites.” Most people want to separate things into simple black and white categories: Yes/No, In/Out, Tastes Great/Less Filling. However, so many things in the world are aligned on a continuous spectrum that one cannot easily draw lines between categories and instead then all meld together like the color transitions in a rainbow.

Dermatological reactions are no different. The better understanding that the public has about the complexity of this situation, the less likely they will erroneously be blaming spiders as the cause of their troubles. Most importantly, if people can stop blaming spiders for all their medical maladies, the actual causes of the wounds may start to surface more regularly and better health care can be provided.

The author is a staff research associate in the department of entomology at the University of California-Riverside and can be reached at rvetter@pctonline.com.