Furuncular myiasis is a skin infestation caused by fly larvae that grow under the skin for days to weeks. It often affects people who live in or travel to tropical areas, and early symptoms of furuncular myiasis can include a painful lump, itching, a feeling of movement, and a small opening in the center. Many living with furuncular myiasis have one boil-like sore, but some have several. Furuncular myiasis is usually not life-threatening, though the skin can become infected if it is not treated. Not everyone will have the same experience, and treatment usually involves removing the larva and cleaning the area, sometimes with antibiotics if a bacterial infection is also present.
How many people live with Furuncular myiasis?
Global prevalence estimates for furuncular myiasis are not consistently reported by a single authoritative source, so there is no reliable worldwide count of how many people are living with it. In the United States, a national estimate is also not consistently reported; published information mainly describes uncommon, usually travel-related cases rather than a counted total.
Overview
Furuncular myiasisSymptoms
With furuncular myiasis, people usually develop a painful, boil-like lump that may feel itchy, tender, or as if something is moving inside. A small central opening often leaks fluid. Early symptoms of furuncular myiasis can also include redness and swelling.
Outlook and prognosis
For most people, furuncular myiasis gets better fully once the larva is removed and the skin is cleaned. The outlook is usually excellent, though some may have short-lived soreness, swelling, or a small scar afterward.
Causes and risk factors
Furuncular myiasis happens when certain fly larvae get into the skin after exposure in tropical or subtropical areas. Risk rises with travel, uncovered skin, insect bites, and drying clothes outdoors where flies can lay eggs. Poor housing and close contact with animals can also increase risk.
Genetic influences
Genetics are not thought to play a major role in furuncular myiasis. Furuncular myiasis usually relates more to insect exposure and environment, though small differences in immune response may affect how strongly skin reacts.
Diagnosis
Furuncular myiasis is usually diagnosed from the skin lesion and a close exam showing a breathing pore or movement. If needed, ultrasound can help confirm it. Diagnosis of furuncular myiasis is often straightforward without extensive testing.
Treatment and drugs
Treatment for furuncular myiasis focuses on removing the fly larva safely, often by a clinician after covering the breathing hole or using a small procedure. If the skin is infected or removal is difficult, antibiotics, pain relief, and wound care may be needed.
Symptoms
A sore that looks like a stubborn boil and does not heal can be one of the main signs of furuncular myiasis. In daily routines, this might show up as a painful bump that catches on clothing or hurts in the shower. Many people with furuncular myiasis notice the spot slowly enlarges over days, often with a tiny opening in the center. The early symptoms of furuncular myiasis can resemble an infected insect bite, which is why it is sometimes mistaken for something more common.
Furuncular myiasis often causes a firm, raised lump that looks like a boil, pimple, or insect bite. The spot usually gets bigger over several days and may not improve with usual skin treatments.
Many people notice a tiny hole or pore in the middle of the bump. This opening helps the larva breathe and can make the sore look different from an ordinary bite.
The area can feel sore to touch, especially when clothing rubs against it or when washing. Some may also feel brief, sharp twinges that come and go.
Itching is common, and some people with furuncular myiasis describe a crawling, wriggling, or pressure-like feeling under the skin. This sensation may become more noticeable when the area is covered or pressed.
How people usually first notice Furuncular myiasis?
People usually first notice furuncular myiasis when what seems like a boil, pimple, or insect bite does not heal and instead becomes a firm, painful, itchy lump with a tiny central opening. Over days, many living with furuncular myiasis may notice a sensation of movement inside the bump, along with clear or blood-tinged fluid draining from it, which can feel unsettling but is a classic clue. The first signs of furuncular myiasis often show up after travel or time spent in tropical or subtropical areas, especially on skin that was exposed to mosquito bites or contact with contaminated clothing or bedding.
Types of Furuncular myiasis
Furuncular myiasis can look a bit different depending on the kind of fly larva involved and where the exposure happened. Symptoms don’t always look the same for everyone. Most types of furuncular myiasis cause a boil-like lump with a small central opening, but the number of sores, the amount of drainage, and the feeling inside the skin can vary. Doctors often separate these forms by the fly involved, because that usually explains the pattern of symptoms.
Human botfly
This form often causes a single painful or itchy lump that slowly enlarges over days to weeks, sometimes with a clear feeling of movement inside. A small opening in the center may leak fluid, and people often notice sharp twinges when the larva shifts.
Tumbu fly
This type more often causes several boil-like bumps at once, especially on the trunk, buttocks, or areas covered by clothing. Many living with this form notice itching and tenderness first, often after clothes or bedding were dried outdoors and worn again.
Cuterebra type
This less common form in people usually causes one furuncle-like lesion, often on the scalp, face, or upper body. The bump may look much like an infected bite at first, but ongoing drainage and a persistent central pore can make the pattern more suggestive of myiasis.
Can I slow down the onset of symptoms?
No, there is no proven way to slow or delay the start of symptoms in furuncular myiasis once a fly larva is already in the skin, because the tender, boil-like bump usually appears as the larva grows. The best-supported steps are about lowering the chance of getting it in the first place, such as using insect repellent, wearing clothing that covers the skin, and in places where this is common, drying clothes well and ironing them before wearing them, since some flies can lay eggs on fabric. These steps may reduce risk but cannot guarantee prevention, and getting medical care early if a new painful bump appears after travel can help the larva be removed sooner and limit discomfort.
What genetics can tell you about symptoms
For furuncular myiasis, genetics usually does not tell you much about symptoms because this condition is caused by fly larvae in the skin, not by an inherited gene change. The main differences in symptoms, such as a painful boil-like lump, itching, a feeling of movement, or how soon symptoms start, are mostly linked to the type of fly, where the larva is in the body, and how many larvae are present. While normal differences in immune response may affect how inflamed or uncomfortable the area becomes, there are no well-established genetic markers that reliably predict which symptoms someone will have or how severe they will be.
Causes and risk factors
Furuncular myiasis starts when larvae from certain tropical flies enter the skin. This can happen after a fly or mosquito bite, or when eggs on clothing or bedding hatch after touching the skin. Risk factors for furuncular myiasis include living in or traveling to warm rural regions, drying clothes outside, and sleeping or working where biting insects are common. There are no known genetic risk factors, and some risks are modifiable (things you can change), others are non-modifiable (things you can’t). Uncovered skin, close contact with animals, and not using insect repellent or protective clothing can also raise risk.
What are the most common causes or risk factors?
Furuncular myiasis usually happens when certain flies lay eggs on skin, on clothing or towels, or on biting insects like mosquitoes, and the tiny young flies then get into the skin. The biggest risk factors are living in or traveling to tropical areas in Africa or Central and South America, spending a lot of time outdoors with exposed skin, close contact with animals, and wearing clothes or using bedding that were dried outside and not ironed first. It is not inherited, so family history is not considered a risk factor.
Environmental and biological risk factors
Furuncular myiasis is more likely when skin is exposed to certain flies or biting insects in warm regions where these parasites live. The risk usually comes from where you are and what your skin comes into contact with, rather than from another person. Doctors often group risks into internal (biological) and external (environmental).
Furuncular myiasis is most common in tropical and subtropical parts of Africa and Central or South America where the responsible flies live. Living in or traveling to these regions raises the chance of exposure.
Warm, humid weather and rainy seasons help the flies breed and survive. Risk can rise during months when fly numbers are highest.
In some regions, fly eggs are carried by biting insects such as mosquitoes and then transferred to skin. Places with many biting insects can raise the risk of furuncular myiasis.
Some flies lay eggs on damp clothing, bedding, or towels, and sometimes on soil or sand. When these materials touch skin, the tiny larvae can hatch and burrow in.
Genetic risk factors
Furuncular myiasis is not known to be caused by inherited gene changes, and there are no proven genetic risk factors for furuncular myiasis. It does not usually run in families the way genetic conditions do. Doctors do not use genetic testing to predict who will get it. Current evidence suggests this condition develops for reasons other than a person’s DNA.
Inherited changes: No specific inherited gene change has been shown to cause furuncular myiasis. Because of this, genetic testing is not a routine part of assessing risk.
Family history: Furuncular myiasis does not have a known pattern of being passed from parent to child. Having a relative who had it does not, by itself, mean you inherited a higher chance of getting it.
Ancestry background: There is no proven evidence that any ancestry group has a DNA-based susceptibility to furuncular myiasis. Differences in how often it is seen in different places are not considered proof of a genetic cause.
Immune genes: Researchers have not identified immune-system genes that clearly explain who develops the usual boil-like skin form of furuncular myiasis. If you are searching for early symptoms of furuncular myiasis, those signs do not point to an inherited disorder.
Lifestyle risk factors
Certain daily habits can raise or lower the chance of developing furuncular myiasis, especially during travel or in places where botfly or tumbu fly exposure is possible. The main lifestyle risk factors for furuncular myiasis involve how clothing is handled, how skin is protected, and how minor skin injuries are cared for. These behaviors do not guarantee infection, but they can affect whether fly eggs reach the skin and develop into larvae.
Wearing clothes, towels, or bedding that were dried outdoors and used without hot ironing can increase risk if eggs were deposited on the fabric. This is especially relevant when damp items are worn directly against the skin.
Spending time outdoors with more uncovered skin can make it easier for larvae to reach the body through bites or direct contact. Using protective clothing consistently may reduce the chance of skin infestation.
Poor care of cuts, sores, or draining skin lesions can make the skin more vulnerable to larval entry. Cleaning and covering broken skin promptly may lower the risk of local infestation.
Infrequent washing of clothes, bedding, or the body after heavy sweating and outdoor exposure can allow contaminated materials to stay in contact with the skin longer. Good hygiene helps remove possible eggs and supports the skin barrier.
Risk prevention
Furuncular myiasis is usually prevented by avoiding contact with flies and the eggs they leave on skin, clothing, or nearby insects. For many, this means thinking ahead before travel, especially in tropical and subtropical areas where this problem is more common. Prevention is about lowering risk, not eliminating it completely. If you have a new painful boil-like lump after travel, early symptoms of furuncular myiasis are worth getting checked promptly.
Use an insect repellent on exposed skin and clothing to lower the chance of bites from flies or mosquitoes that can carry larvae. This matters most during travel or outdoor activity in areas where furuncular myiasis occurs.
Long sleeves, long pants, socks, and closed shoes can make it harder for insects to reach your skin. Light, loose clothing is often easier to wear in hot climates while still adding protection.
Sleeping under an insecticide-treated bed net can reduce nighttime insect contact. Screens, air conditioning, and keeping windows closed when possible can also help keep flies indoors.
In some regions, certain flies lay eggs on damp clothes or towels left out to dry. Drying clothes in a dryer or ironing them well before wearing can kill eggs and lower the risk of furuncular myiasis.
Can you prevent Furuncular myiasis?
Furuncular myiasis cannot always be fully prevented, but you can lower the risk by avoiding contact with the flies that cause it, especially in places where it is more common. Wearing long sleeves and pants, using insect repellent, sleeping under bed nets, and making sure clothes and bedding are washed well and fully dried before use, with ironing if advised locally, can all help reduce the chance of getting it.
Transmission
People often ask how furuncular myiasis spreads. Furuncular myiasis happens when certain flies leave eggs on skin, on damp clothing or bedding, or sometimes on biting insects such as mosquitoes; after contact, the tiny larvae can enter the skin. It is not usually passed directly from one person to another, so normal contact like touching, hugging, or sharing a room does not typically spread furuncular myiasis.
Risk is usually linked to travel or time spent in tropical or subtropical areas, especially if clothes or linens have been exposed to flies. Even though it is caused by fly larvae, furuncular myiasis is generally considered low in contagiousness because people with furuncular myiasis do not usually infect others.
When to test your genes
For furuncular myiasis, genetic testing is not useful. This is a skin infestation caused by fly larvae, usually diagnosed from the bump itself, your symptoms, and travel or exposure history. If lesions are painful, draining, or not healing, prompt medical evaluation matters far more than any gene test.
Diagnosis
Furuncular myiasis is usually diagnosed when a sore, boil-like lump does not heal as expected and may seem to move, sting, or drain fluid. In day-to-day life, this can look like a bump that keeps coming back after standard skin treatment or feels oddly painful for its size. Doctors usually begin with a close skin exam, and the diagnosis of furuncular myiasis is often made from the appearance of the lesion and a travel or exposure history.
A clinician closely inspects the lump for a small central opening, swelling, drainage, and other signs that suggest a larva under the skin. The location, shape, and tenderness of the lesion often help distinguish furuncular myiasis from a simple boil or cyst.
Doctors ask when the bump started, how it has changed, and whether there is itching, sharp pain, a crawling sensation, or fluid drainage. Travel to tropical or subtropical areas, insect bites, and contact with drying clothes or bedding outdoors can provide important clues.
A handheld magnifying device may help the doctor see the breathing hole or movement inside the lesion. This can support how furuncular myiasis is diagnosed when the surface findings are subtle.
If the diagnosis is uncertain, an ultrasound can sometimes show a moving larva beneath the skin. This is especially helpful when the lesion is deep, very swollen, or looks like another skin problem.
How is Furuncular myiasis diagnosed?
Furuncular myiasis is usually diagnosed when a clinician examines the skin lump, asks about recent travel or insect exposure, and looks for clues such as a small opening in the center, drainage, or a feeling of movement under the skin. If the cause is not clear from the exam, they may use a magnifying skin tool or an ultrasound scan to look for the larva under the skin. In many cases, the diagnosis is confirmed when the larva is removed and identified.
Stages of Furuncular myiasis
Furuncular myiasis does not have defined progression stages. This is because it is usually a short-term skin infestation that develops over days to weeks rather than a disease that moves through set phases over time. Often the process begins when you notice changes in daily life, such as a tender bump that seems like a boil but does not heal as expected, which can be one of the early symptoms of furuncular myiasis. Doctors usually diagnose it from the skin changes and symptoms, sometimes with a close skin exam or ultrasound, and they monitor it by making sure the larva is removed fully and the area heals without infection.
Outlook and prognosis
The outlook for furuncular myiasis is excellent, because most people recover completely once the larva is removed and the wound is cleaned. Symptoms such as pain, itching, swelling, and drainage usually resolve quickly, and scarring is often minimal if treatment is prompt. Serious complications are uncommon but can include secondary bacterial infection, local tissue damage, or delayed healing if the infestation is not recognized. Death from furuncular myiasis is exceedingly rare, and mortality is generally not expected in otherwise healthy people. Prognosis may be less favorable only in unusual situations, such as multiple lesions, involvement of vulnerable areas like the eye, or significant delay in care.
Long-term effects
For most people, furuncular myiasis gets better fully once the larva is removed and the skin is cleaned. The long-term picture is often reassuring, especially when treatment happens early and there is no deeper infection. Most lasting problems are mild, but some people may have a small scar, temporary skin changes, or ongoing irritation for a short time after treatment for furuncular myiasis.
A round mark or slight scar can remain where the larva was sitting in the skin. This is more likely if the sore was large, inflamed, or picked at before removal.
The area may stay darker or lighter than the surrounding skin for weeks or months after furuncular myiasis. These changes often fade gradually, but in some people they can last longer.
Mild tenderness, itching, or a firm bump can continue for a short time after the larva is removed. This usually settles as the skin heals, although slow healing can happen if the area was inflamed for a while.
If bacteria enter the opening in the skin, the site can become more red, warm, painful, or drain pus. When this happens, healing may take longer and the chance of scarring can increase.
How is it to live with Furuncular myiasis?
Living with furuncular myiasis can be unsettling because what starts as a sore, boil-like bump may become painful, itchy, and feel as if something is moving under the skin, which can make sleep, walking, or wearing clothes uncomfortable depending on where it is. Many people also feel embarrassed or anxious once they learn it is caused by a fly larva, but the condition is usually limited to the skin and is treatable, with symptoms improving once the larva is removed. For people around you, the main impact is often emotional concern rather than medical danger, because this form of myiasis does not usually spread directly from person to person through casual contact.
Treatment and drugs
Furuncular myiasis is treated by removing the larva from the skin and then helping the area heal, which usually brings quick relief from the painful, boil-like lump. Treatment often looks different for each person, but doctors commonly start by covering the breathing hole in the skin with petroleum jelly or a similar ointment to force the larva toward the surface, then gently removing it with sterile tools. In some cases, especially if the larva is deep or hard to remove, a doctor may numb the area first or make a small opening to take it out safely. After removal, the skin is cleaned, and antibiotics are only needed if there is a bacterial infection rather than for furuncular myiasis itself. If you notice increasing redness, swelling, pus, fever, or the area is not improving, it is important to get medical care because these can be signs of complications.
Can you cure Furuncular myiasis?
Yes. Furuncular myiasis, which is a boil-like skin lump caused by a fly larva under the skin, can usually be cured by safely removing the larva, often with a simple treatment in a clinic, and the skin usually heals well afterward. If the area is irritated or gets a bacterial infection, your doctor may also treat that, but most people recover fully once the larva is removed.
Non-drug treatment
Furuncular myiasis can feel unsettling day to day, often causing a painful, boil-like lump that seems to move or drain without healing normally. Treatment usually focuses on safely removing the larva, protecting the skin, and helping the area heal with as little damage as possible. Non-drug treatments often lay the foundation for care, especially when a clinician can confirm what is causing the sore. Not every approach works the same way, so the best method depends on where the larva sits and how inflamed the skin is.
Covering the opening with petroleum jelly or a similar airtight layer can block the larva’s air supply and encourage it to move toward the surface. This can make removal easier, but it should be done carefully because part of the larva can remain behind if it is pulled out too soon.
A clinician may gently widen the skin opening and remove the larva with forceps or a small procedure under sterile conditions. This is often the most reliable option when people have early symptoms of furuncular myiasis or when the bump is painful, swollen, or in a sensitive area.
After removal, cleaning the area and using a simple dressing helps lower the risk of infection and supports healing. You might notice the skin settles over several days, although a small opening can take a little longer to close fully.
A follow-up visit may be needed if pain, redness, drainage, or swelling continue after treatment. Sometimes, self-care strategies are not enough if part of the larva remains, and the area may need to be re-examined and cleaned again.
Your genes may have an impact on how drugs work for you
For furuncular myiasis, treatment usually centers on removing the larva rather than long-term medicine, so a person’s genes do not usually play a major role in care. If medicine is used, such as a parasite-killing treatment in some cases, people can still vary in how strongly it works or how likely side effects are, but this is usually influenced more by age, overall health, pregnancy, other medicines, and the exact type and location of the infestation than by inherited genetic differences. In everyday practice, genetic testing is not a routine part of treating furuncular myiasis.
Pharmacological treatments
Medicines are not always the main treatment for furuncular myiasis, because the larva often needs to be removed as well. When drugs are used, they are mainly to kill or weaken the larva, ease pain, or treat a skin infection around the boil-like lump. Not everyone responds to the same medication in the same way. In many living with furuncular myiasis, the exact plan depends on where the lesion is, how inflamed it is, and whether there are signs of infection.
Ivermectin is the drug most often used when medicine is needed for furuncular myiasis, especially if removal is difficult or there are several lesions. It may be given by mouth, and in some cases a topical form is used to help kill or paralyze the larva before extraction.
Antibiotics are not routinely needed for the larva itself, but they may be prescribed if the surrounding skin becomes secondarily infected. If there is spreading redness, warmth, pus, or fever, a doctor may choose an antibiotic that targets common skin bacteria.
Pain relievers such as acetaminophen or ibuprofen can help with soreness, throbbing, and swelling around the lesion. For many, this can mean being more comfortable while waiting for removal or during recovery afterward.
Lidocaine may be used to numb the area before the larva is removed, making the procedure easier to tolerate. In some cases, injected lidocaine also increases pressure under the skin and can help push the larva toward the surface.
Genetic influences
If a tender, boil-like lump shows up after travel or time in places with biting flies, furuncular myiasis is usually explained by exposure, not by something passed down in families. It’s natural to ask whether family history plays a role, but furuncular myiasis is not considered a genetic condition. There is no known inherited gene change that causes it, and if several relatives develop it after the same trip or outdoor setting, that usually reflects shared exposure to the same flies. Researchers think small differences in immune response may affect how much redness, swelling, or discomfort someone has, but genetics is not thought to be a major reason why furuncular myiasis happens. For most people, prevention and treatment matter far more than inherited risk.
Is Furuncular myiasis genetic?
Genetics are not thought to play a major role in furuncular myiasis. Furuncular myiasis usually relates more to insect exposure and environment, though small differences in immune response may affect how strongly skin reacts.
Having a genetic risk is not necessarily a diagnosis
Genetic variants are a usual feature of human biology and are common throughout the general population. Most do not have a direct effect on health and instead are part of normal human diversity. For many genes, carrying a variant connected to a condition indicates a possible association rather than a confirmed diagnosis, especially when several genes and environmental factors are involved. In some instances, though, a single well-characterized variant in a particular gene is enough to confirm the diagnosis.
Pharmacogenetics—how genetics influence drug effects
For most people with furuncular myiasis, treatment is guided more by where the larva is, how inflamed the skin is, and whether there is a bacterial skin infection than by inherited genes. Doctors usually remove the larva and may use local numbing medicine, pain relief, or sometimes ivermectin, so the main plan is based on the skin problem itself rather than a genetic test. Genetics is only one factor: inherited differences can affect how quickly some people process pain medicines or other drugs used during treatment, which can change side effects or how well a medicine works. These gene effects are not specific to furuncular myiasis, and pharmacogenetic testing is not a routine part of care for this condition. If treatment for furuncular myiasis is not working as expected, your doctor may look more closely at the medication choice, dose, other health conditions, and possible drug interactions.
Interactions with other conditions
Furuncular myiasis can be harder to recognize in people who already have skin problems such as boils, infected insect bites, eczema, or ongoing wound infections, because the bump may look similar at first. Someone might notice their symptoms flare when another condition is active, especially if diabetes, poor circulation, or a weakened immune system makes the skin slower to heal or more prone to infection. The main interaction is usually with bacterial skin infection: the opening in the skin can let germs in, which may add redness, warmth, pus, or fever on top of the discomfort from furuncular myiasis itself. In tropical and subtropical areas, doctors may also need to tell it apart from cutaneous leishmaniasis, tungiasis, scabies, or an inflamed cyst, since the early symptoms of furuncular myiasis can overlap with these conditions. If you are living with another skin or immune-related condition, prompt assessment matters so treatment targets the larva as well as any infection or other illness happening at the same time.
How genes can cause diseases
Humans have more than 20,000 genes, each carrying out one or a few specific functions in the body. One gene instructs the body to digest lactose from milk, another tells the body how to build strong bones and another prevents the body's cells from beginning to multiply uncontrollably and developing into cancer. As all of these genes combined are the building instructions for our body, a defect in one of these genes can have severe health consequences.
Through decades of genetic research, we know the genetic code of any healthy/functional human gene. We have also identified that in certain positions on a gene, some individuals may have a different genetic letter from the one you have. We call these hotspots "Genetic Variations" or "Variants" in short. In many cases, studies have been able to show that having the genetic letter "G" in the position makes you healthy, but having the letter "A" in the same position disrupts the gene function and causes a disease. Genopedia allows you to view these variants in genes and summarizes all that we know from scientific research, which genetic letters (Genotype) have good or bad consequences on your health or on your traits.
What other conditions can cause similar symptoms to Furuncular myiasis?
Furuncular myiasis is most often mistaken for a boil or skin abscess, an infected bug bite, an inflamed cyst, or an irritated hair follicle. These can all cause a tender, red lump that may itch, swell, or leak fluid, so at first they can look very similar. In people who have traveled, doctors may also need to rule out other tropical skin infections, especially if the sore does not heal as expected.
History
People living in tropical and subtropical regions have described painful, boil-like skin lumps for centuries, sometimes noticing a small opening in the center and a strange sense of movement under the skin. Across cultures and centuries, furuncular myiasis was observed long before doctors understood exactly what caused it. In daily life, it could look a lot like an infected bite or a stubborn boil that would not heal in the usual way.
As travel and tropical medicine developed in the 1800s and early 1900s, doctors began writing clearer descriptions of these skin lesions and linking them to the immature stage of certain flies. That helped separate furuncular myiasis from ordinary skin infections, cysts, and other causes of painful bumps. Early reports often came from Latin America and Africa, where the condition was already familiar to many local communities and where people had long recognized that certain skin sores behaved differently from a typical abscess.
Later in the 20th century, laboratory studies and field research showed more clearly how the fly life cycle leads to the skin changes people experience. This also explained why furuncular myiasis can appear after time outdoors, contact with clothing dried outside in some regions, or travel to areas where the flies are common. For many, this history matters because the early symptoms of furuncular myiasis can still be mistaken for a spider bite, infected hair follicle, or simple boil.
Today, furuncular myiasis is well recognized in dermatology, travel medicine, and infectious disease care. Awareness has improved diagnosis and treatment, especially for travelers who return home with a persistent, tender skin lump that seems out of proportion to a normal insect bite. Even so, the condition is still unfamiliar in places where it is uncommon, so its history remains useful: it reminds clinicians and patients alike that a common-looking skin bump can sometimes have a very different cause.