33 Things Doctors Must Remember About Bug Bites
I really do NOT have a fetish about bugs or bug bites—even though I’ve written about them many times before.
It’s just that people keep asking questions, others are continually writing about them and there’s just so many interesting photos available to accompany articles.
The Lone Star Tick, adult, nymphal form and paper match
I’m revealing the thirty-three (or so) things that doctors need to keep in mind about bug bites and the patients that are bitten—and we’ve already bitten off about half of them in the first article.
More Bugs
and the problems they cause
The Lone Star Tick – Associated With What Disease
The photo above is of the “Lone Star Tick” (Amblyomma americanum) and shows its adult and nymphal forms next to a match head for comparison.
If you were one of the students, my question would be: “what disease is the tick pictured here associated with?” I’ll give you a hint. It’s either 1- Lyme Disease; 2- Ehrlichiosis; 3- Babesiosis; or, 4- Colorado tick fever.
Ehrlichiosis
Of course! It’s Ehrlichiosis. You know, that disease that nobody knows how to pronounce and gives you symptoms anywhere from nothing at all to fever, seizures, coma and death with cardiac failure, or renal, or lungs.
Getting serious, it’s a real bug-a-boo to diagnose early—unless the patient comes in and says: “I got bit by a tick.”
Most of this disease comes from this tick in the photograph, although there are a couple related types (chaffeensis and ewingii) that cause disease in humans too.
They have little appendages on their mouths that sort of “pooch up” the skin into a mound so their blood-absorbing tube covered with blade-like scales can puncture it. Once their “sucker” hits a blood vessel, glands secrete a little cone of cement that keeps the tick attached until it’s full and desires to leave.
And, thankfully for the rest of us, they mainly inhabit the southcentral and southeast US states.
Doctors should remember to begin treatment with Doxycycline any time they suspect ehrlichiosis.
I remember the Boy Scout and other first aid manuals used to have several neat little tricks to remove a tick without squeezing them for fear of pushing their “juices” into the wound. Now days we just use tweezers and try to grab the thing right next to the skin without smashing either the head or the body.
Pulling gently and slowly often eventually breaks that cone and eases the tick out. If you twist or jerk, the mouth-parts and head may remain in the skin. Of course clean it with soap, water and alcohol afterward.
Some patients have previously shown anaphylactic reactions when they’ve tried to remove ticks. In Australia, where this seems to be more common, people are advised to freeze the tick with some wart-freezing spray then go to the doctor to have it carefully removed. Or, without wart-freeze they just use the ether-containing Aerostart they use to start their trucks with.
Muscle and joint pain, eye pain, fever and rash
As long as we’re talking about traveling, this teen came back from Thailand with what they thought was the flu but then this rash appeared—influenza doesn’t usually give a rash.
He’s had a headache, a fever for a couple days, a headache and lots of pain—in his muscles, joints and even behind his eyes. This time you get to examine the patient and find a flushed, red, mottled rash on his face, neck, chest and legs.
You note that the rash has little islands of healthy skin in it—very peculiar! So, what does this look like to you? West Nile encephalitis, Zika, Dengue Fever or Leptospirosis?
Dengue Fever
Of course, you got it right off—Dengue Fever. And just to prove you were right, the fever ended the day you saw him and he developed petechiae in his mouth and eyes.
The mosquito of the Aedes genus is found all over the world in the subtropical and tropical areas and is the main vector for Dengue Fever—also called “breakbone fever” because of how severe the muscle and joint pain afflicts its victims.
The symptoms are really varied which makes diagnosis a bit difficult; but, a prodrome of chills, mottling of the skin and facial flushing is quite specific for Dengue—especially in an endemic area with mosquitos.
Sometimes a “tourniquet test” is helpful in the diagnosis of Dengue. Inflate your blood pressure cuff on the upper arm to halfway between the top and bottom numbers and leave it there for 5 minutes.
If more than 20 petechiae per square inch appear the test is considered “positive” and, in the setting we’ve described, strongly suggests Dengue.
We have no specific antiviral treatment. All you can do is take supportive measures with pain relievers, fluids and bed rest.
Scientist have experimented with an odd procedure in Brazil with good success. They bread male mosquitos that were tetracycline-dependent— without it they would die.
Then they released all these defective mosquitos into the wild which mated with the females and then died but not before passing on their tetracycline-dependence to their larvae—which also died and dramatically decreased Dengue fever in the area.
Conjunctivitis, rash and joint pain
After a trip to Venezuela a patient of yours comes in with “pink eye” (conjunctivitis), the rash depicted in the photo and joint pains.
What about this one, does this look like Dengue too? Or, could it be West Nile Encephalitis, Zika or Leptospirosis?
Zika
You’re getting good at this. Of course it’s Zika Virus infection. The big tip-off was traveling to South America but it’s also here in the U.S. on both coasts and in the South—mostly from people who have traveled south.
Like Dengue, Zika is spread by the genus Aedes mosquito BUT Zika can also be transmitted by sexual contact too.
The conjunctivitis caused by Zika virus infection is shown in the photo but there is also the rash and joint pain. In fact, the symptoms are almost like Dengue but much less pronounced (like a mild “flu”) and sometimes none at all.
There IS however a correlation between Zika and devastating birth defects including microcephaly (small head).
It requires restating: Mosquito bites seen in a physician’s office need to be followed up by probing questioning. There are an estimated 700 million annual cases of mosquito-transmitted diseases worldwide, resulting in nearly a million deaths.
In addition to dengue fever and Zika, mosquitoes can also transmit diseases such as malaria, yellow fever, Chikungunya, and West Nile virus, as well as other viral encephalitides.
Lesion on Finger From Caribbean Vacation
Ok, one last vacation disease, I promise. Look at the photo, if you can stand it, and tell me what you think caused it: Tick, Botfly, Hookworm or Chigoe fleas.
A pustular lesion on this boys finger has an erythematous base and is quite painful with swelling, tenderness and some limitation of motion—plus being a little itchy.
D.Chigoe fleas (Tunga penetrans)
I said this boy had vacationed but he could have gotten this lesion from around home too.
An infestation of the burrowing flea, T. penetrans or its relatives, is often called “chigger fleas,” sand fleas, jiggers or chiggers. The flea secretes compounds that help it burrow into tissues where it completes its life cycle, munches on tissues and lays eggs.
Known as tungiasis the prognosis is good IF sterile methods are followed for extraction and a secondary infection doesn’t occur like bacteremia, septicemia, lymphangitis, tetanus or gas gangrene; which may even follow attempts to remove the fleas.
One flea can rapidly produce hundreds of eggs which hatch.
Doctors must usually enlarge the opening with sterile instruments, in order to remove it’s capsule and swollen body, then curette or excise the entire nodule.
The remaining crater should be thoroughly cleansed and covered with a topical antibiotic cream to prevent secondary infection.
Health Care Worker, Complains of Spider Bite
A teen health care worker sees you with this wound and says he was bitten by a spider during his sleep. To complicate matters he is diabetic but denies any recent outdoor activities.
He didn’t see what bit him but it started with a pustule and is painful. You see the pustule in the photo, what do you think is the cause: Brown Recluse spider, Deer Tick, Flea, or “this lesion is not a bug bite”?
Not a Bug Bite
This wasn’t really a fair question, I’ve seen more than one envenomation look pretty close to this; but, when one sees a diabetic patient, infection needs to be close to the top of the list for this kind of thing because they are susceptible to this kind of infection. Being a health care worker is a “double whammy.”
Additionally, a spider bite is really common as an explanation given for skin lesions without obvious antecedent cause—and is typically spurious. Usually it’s when asleep and unable to witness the spider.
This lesion is typical of a staphylococcal cellulitis with drainage. The doctor should take a culture of the wound and drainage then drain any abscess if one is present.
That should be followed by an antibiotic which is good for both methicillin-sensitive and methicillin-resistant Staph Aureus.
College Teen With “Bites”
Last one. A college boy comes to your office with intensely itchy, red bumps on his back and ankles. They look sort of linear to you on both sides of his spine.
What do you think? Could this be: Mosquitoes, spiders, bedbugs or fleas?
Cimex lectularius – Bedbugs
Cleverly you ask a few questions because you know about college boys and fraternities. He said he had spent a night on a fraternity couch and the diagnosis was almost made.
Bedbugs conceal themselves in cracks and folds where humans sleep. They are attracted to the smell of their own species’ urine so tend to aggregate in spots where others have successfully fed. They inject a self-dispersing saliva which digests cells and then suck up the liquefied slurry with their feeding tube.
Bedbugs are gregarious diners so rarely come in singles. Bites are often in multiple rows where the “bug” has fed, moved over and fed again.
Incredibly, some people have no response at all to the bites; but, most often people develop 2-5 millimeter itchy, raised red papules at the feeding site. Compounds in the bug’s saliva cause reactions such as redness, wheals, vesicles or even hemorrhagic nodules.
Untreated they usually disappear within a week; BUT, there is usually such severe itching that the bites open and become infected.
Currently, we don’t know that they cause disease but we do know that getting rid of them is getting harder because they are becoming resistant to pesticides.
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