Can You Be Allergic To Silverfish, And What Can You Do About Pest Control If You Have An Infestation?

At least a quarter of American adults are at least mildly scared of "bugs", and research gives us some insights into why insects and arachnids make many of us feel so uncomfortable. To boil this common fear of creepy crawlies down to its essence, being cautious, and especially of anything radically different from us, pays off in evolutionary terms — especially since many bugs can hurt us. 

Silverfish look so alien that they could easily serve as inspiration for a sci-fi movie, so we don't blame you if you find yourself letting out a subconscious little scream when one falls out of that old book you dug out of the basement. They're also bad for quite a lot of the things you likely keep in your home; another good reason not to want them anywhere near you.

Basic facts: What do you need to know about silverfish?

Silverfish (Lepisma saccharinum) are shiny, and often silvery, little — from really very tiny to abut 25 mm in length —  arthropods. They have two long antennae and two quite impressive cerci, as well as a filament at the end, or in layperson's terms, five imposing spiky bits sticking out of their fronts and backsides. Their tapered bodies and fluid wiggling motions remind many people of fish, and that's where they got their popular name. Silverfish are related to some of the oldest insects ever to have crawled around on our planet, and that's a pretty cool fact. 

If you think you've seen silverfish around your home, though, these aren't the kinds of trivia answers you've been looking for. Instead, you'd probably more interested to know that:

• Silverfish thrive in dark, humid environments — which means that if you've seen one or a couple scurrying away, you'll probably find more in that cardboard box full of old newspapers, that shelf with clothes not currently in season, at the back of your bookshelf, or even in your pile of old tax papers. 
• Silverfish feed on polysaccharides like cellulose (the stuff you find in paper) — though many people know that "silverfish eat books", their diet goes beyond paper and also includes coffee, sugar, hair, dandruff, dead insect bits, cotton, silk, linen, and certain paints and glues. This means that silverfish can cause significant damage to your home and any stockpiles of food you may be holding onto, if not stored properly. 
• Silverfish reproduce often and in large numbers, but can live for years. That means thriving populations can quickly take up permanent residence in your home.
• Over the course of their lifecycle, silverfish moult dozens of times, and more often than other insects, leaving the exoskeleton bits they no longer need around your home.
• Not seeing silverfish doesn't mean that they don't live right under your nose — studies in which the contents of household dust were analyzed showed silverfish scales in many homes, despite the human inhabitants being completely oblivious to their presence. Silverfish are probably more scared of you than you are of them, and do their best to keep away. Yellow-tinted residue on books and paper, and jagged little holes in wallpaper, books, papers, or clothes are some of the signs that they're among you.

How can silverfish affect your (resporiratory) health?

Because silverfish moult their exoskeletons so often, and their populations easily grow in number, homes with silverfish infestations will suffer a buildup of left-behind scales. Both these scales and the dust that accummulates on them can produce allergic reactions in some people. If you are also allergic to things like pollen, molds, and dust, you are likely to also have a problem with silverfish. 

An allergic reaction to silverfish could cause:

• Coughing
• Sneezing
• A runny or congested nose
• Puffy, red, irritated eyes
• Skin rashes
• Asthma attacks in people suffering from allergic asthma

While over-the-counter and prescription medications can help keep both allergies and asthma under control, the better answer is, of couse, to eliminate the allergen. In the case of silverfish, that is easier said than done — but nonetheless a necessary endeavor, especially if your umwanted little guests are keeping you up all night by forcing respiratory symptoms on you. 

How do you get rid of a silverfish infestation?

Aggressive science-based recommendations that should at least help you reduce the silverfish population in your home if you are already dealing with an infestation include:

• Reducing humidity levels, including by using a humidifier and considering installing better air vents.
• Vacuum thoroughly after every meal and snack, and make sure to regularly hoover those hard-to-reach spaces in your home where other food sources, including your hair and dead skin cells, may accumulate, as well. Yup, that means in and under your bed, cushions, curtains, and upholstery as well.
• Pack your food stockpiles away in airtight containers, removing them as a culinary option for silverfish. The outside of your home should be painted well, too.
• Get rid of extra papers and old clothes that you really don't need or want.
• Spiders eat silverfish. Don't kill or remove spiders from your home.
• Set traps by putting simple plastic containers in dark places, with tape lining the inside. Silverfish will naturally go inside, but can't escape.

If you're talking poison, boric acid is probably the safest choice, given that it's less toxic to humans and pets than the other options. Like other pest control options, you use boric acid by sprinkling it in areas where you know lots of silverfish congregate. You can also dilute boric acid in water and spray it into nooks and crannies.

Diatomaceous Earth is a naturally-occurring substance that dehydrates and kills silverfish and other insects, but it's another potential respiratory hazard to people allergic to silverfish, and should not be inhaled. If you have pets, children, or both, you need to make sure you can keep it away from them if you choose this option. 

Pyrethrin is another option. Less harsh of a pesticide than many others, concentrate it in crevices you don't personally usually touch but where you know silverfish have built a home.

A final word

A descendant of ancient creatures, the silverfish certainly takes advantage of modern human homes by feeding on everything we discard or don't clean up properly, hiding, often, quite literally under our noses in numbers that would shock us. As allergies build up over time, the longer you live with silverfish, the more likely you are to have a reaction. Take steps to tackle your silverfish infestation, but if you find yourself having trouble breathing because of them, don't forget to seek medical attention as well.