Formication
Encyclopedia
Formication is the medical term for a sensation that resembles that of insect
s crawling on (or under) the skin. It is one specific form of a set of sensations known as paresthesia
, which also include the more common prickling, tingling sensation of "pins and needles". Formication is a well documented symptom that has numerous possible causes.
The experience of formication may sometimes cause feelings of itchiness, tingling, pins and needles, burning, or even pain. When it is perceived as itchiness, it may trigger the scratch reflex
and because of this, some people who are suffering from the sensation are at risk of causing skin damage through excessive scratching. More rarely, susceptible individuals who fixate on the sensation may develop delusional parasitosis
, becoming convinced that this sensation is being caused by actual insects, despite repeated reassurances from physicians, pest control
experts, and entomologists.
The term is derived from formica, the Latin word for ant
.
(i.e. hormone withdrawal). Other causes are medical conditions such as diabetic neuropathy
, skin cancer
, syphilis
, Lyme disease
or herpes zoster
.
Formication can also sometimes be experienced during high fever
s. Itching, tingling and formication often occur when surfacing from a dive or during ascent to altitude (decompression sickness
or "the bends").
It can be a side effect of Ritalin (methylphenidate
), Adderall
(dextro/levo-amphetamine) and Lunesta (eszopiclone) and other prescription drug
s or of cocaine
or amphetamine
s. (Accordingly, it goes by the slang
term "coke bugs".) Formication can also be a withdrawal symptom of weaning oneself off cocaine or amphetamine. It can also accompany alcohol withdrawal in alcoholics, along with delirium tremens
, and can often be accompanied by visual hallucinations of insects.
word formica, meaning "ant
", precisely because of this similarity in sensation to that of crawling insects. The term has been in use for several hundred years. In the 1797 edition of the Encyclopædia Britannica
, a description of the condition raphania includes the symptom:
Described again in an instructional text from 1890:
Insect
Insects are a class of living creatures within the arthropods that have a chitinous exoskeleton, a three-part body , three pairs of jointed legs, compound eyes, and two antennae...
s crawling on (or under) the skin. It is one specific form of a set of sensations known as paresthesia
Paresthesia
Paresthesia , spelled "paraesthesia" in British English, is a sensation of tingling, burning, pricking, or numbness of a person's skin with no apparent long-term physical effect. It is more generally known as the feeling of "pins and needles" or of a limb "falling asleep"...
, which also include the more common prickling, tingling sensation of "pins and needles". Formication is a well documented symptom that has numerous possible causes.
The experience of formication may sometimes cause feelings of itchiness, tingling, pins and needles, burning, or even pain. When it is perceived as itchiness, it may trigger the scratch reflex
Scratch reflex
The scratch reflex is a response to activation of sensory neurons whose peripheral terminals are located on the surface of the body. Some sensory neurons can be activated by stimulation with an external object such as a parasite on the body surface. Alternately, some sensory neurons can respond to...
and because of this, some people who are suffering from the sensation are at risk of causing skin damage through excessive scratching. More rarely, susceptible individuals who fixate on the sensation may develop delusional parasitosis
Delusional parasitosis
Delusional parasitosis is a form of psychosis whose victims acquire a strong delusional belief that they are infested with parasites, whereas in reality no such parasites are present...
, becoming convinced that this sensation is being caused by actual insects, despite repeated reassurances from physicians, pest control
Pest control
Pest control refers to the regulation or management of a species defined as a pest, usually because it is perceived to be detrimental to a person's health, the ecology or the economy.-History:...
experts, and entomologists.
The term is derived from formica, the Latin word for ant
Ant
Ants are social insects of the family Formicidae and, along with the related wasps and bees, belong to the order Hymenoptera. Ants evolved from wasp-like ancestors in the mid-Cretaceous period between 110 and 130 million years ago and diversified after the rise of flowering plants. More than...
.
Differential diagnosis
Causes of formication include normal states such as onset of menopauseMenopause
Menopause is a term used to describe the permanent cessation of the primary functions of the human ovaries: the ripening and release of ova and the release of hormones that cause both the creation of the uterine lining and the subsequent shedding of the uterine lining...
(i.e. hormone withdrawal). Other causes are medical conditions such as diabetic neuropathy
Diabetic neuropathy
Diabetic neuropathies are neuropathic disorders that are associated with diabetes mellitus. These conditions are thought to result from diabetic microvascular injury involving small blood vessels that supply nerves in addition to macrovascular conditions that can culminate in diabetic neuropathy...
, skin cancer
Skin cancer
Skin neoplasms are skin growths with differing causes and varying degrees of malignancy. The three most common malignant skin cancers are basal cell cancer, squamous cell cancer, and melanoma, each of which is named after the type of skin cell from which it arises...
, syphilis
Syphilis
Syphilis is a sexually transmitted infection caused by the spirochete bacterium Treponema pallidum subspecies pallidum. The primary route of transmission is through sexual contact; however, it may also be transmitted from mother to fetus during pregnancy or at birth, resulting in congenital syphilis...
, Lyme disease
Lyme disease
Lyme disease, or Lyme borreliosis, is an emerging infectious disease caused by at least three species of bacteria belonging to the genus Borrelia. Borrelia burgdorferi sensu stricto is the main cause of Lyme disease in the United States, whereas Borrelia afzelii and Borrelia garinii cause most...
or herpes zoster
Herpes zoster
Herpes zoster , commonly known as shingles and also known as zona, is a viral disease characterized by a painful skin rash with blisters in a limited area on one side of the body, often in a stripe...
.
Formication can also sometimes be experienced during high fever
Fever
Fever is a common medical sign characterized by an elevation of temperature above the normal range of due to an increase in the body temperature regulatory set-point. This increase in set-point triggers increased muscle tone and shivering.As a person's temperature increases, there is, in...
s. Itching, tingling and formication often occur when surfacing from a dive or during ascent to altitude (decompression sickness
Decompression sickness
Decompression sickness describes a condition arising from dissolved gases coming out of solution into bubbles inside the body on depressurization...
or "the bends").
It can be a side effect of Ritalin (methylphenidate
Methylphenidate
Methylphenidate is a psychostimulant drug approved for treatment of attention-deficit hyperactivity disorder, postural orthostatic tachycardia syndrome and narcolepsy. It may also be prescribed for off-label use in treatment-resistant cases of lethargy, depression, neural insult and obesity...
), Adderall
Adderall
Adderall is a brand name of amphetamine salts–based medication used for attention-deficit hyperactivity disorder and narcolepsy. It is a brand-name psychostimulant medication composed of racemic amphetamine aspartate monohydrate, racemic amphetamine sulfate, dextroamphetamine saccharide, and...
(dextro/levo-amphetamine) and Lunesta (eszopiclone) and other prescription drug
Prescription drug
A prescription medication is a licensed medicine that is regulated by legislation to require a medical prescription before it can be obtained. The term is used to distinguish it from over-the-counter drugs which can be obtained without a prescription...
s or of cocaine
Cocaine
Cocaine is a crystalline tropane alkaloid that is obtained from the leaves of the coca plant. The name comes from "coca" in addition to the alkaloid suffix -ine, forming cocaine. It is a stimulant of the central nervous system, an appetite suppressant, and a topical anesthetic...
or amphetamine
Amphetamine
Amphetamine or amfetamine is a psychostimulant drug of the phenethylamine class which produces increased wakefulness and focus in association with decreased fatigue and appetite.Brand names of medications that contain, or metabolize into, amphetamine include Adderall, Dexedrine, Dextrostat,...
s. (Accordingly, it goes by the slang
Slang
Slang is the use of informal words and expressions that are not considered standard in the speaker's language or dialect but are considered more acceptable when used socially. Slang is often to be found in areas of the lexicon that refer to things considered taboo...
term "coke bugs".) Formication can also be a withdrawal symptom of weaning oneself off cocaine or amphetamine. It can also accompany alcohol withdrawal in alcoholics, along with delirium tremens
Delirium tremens
Delirium tremens is an acute episode of delirium that is usually caused by withdrawal from alcohol, first described in 1813...
, and can often be accompanied by visual hallucinations of insects.
History
Formication is etymologically derived from the LatinLatin
Latin is an Italic language originally spoken in Latium and Ancient Rome. It, along with most European languages, is a descendant of the ancient Proto-Indo-European language. Although it is considered a dead language, a number of scholars and members of the Christian clergy speak it fluently, and...
word formica, meaning "ant
Ant
Ants are social insects of the family Formicidae and, along with the related wasps and bees, belong to the order Hymenoptera. Ants evolved from wasp-like ancestors in the mid-Cretaceous period between 110 and 130 million years ago and diversified after the rise of flowering plants. More than...
", precisely because of this similarity in sensation to that of crawling insects. The term has been in use for several hundred years. In the 1797 edition of the Encyclopædia Britannica
Encyclopædia Britannica
The Encyclopædia Britannica , published by Encyclopædia Britannica, Inc., is a general knowledge English-language encyclopaedia that is available in print, as a DVD, and on the Internet. It is written and continuously updated by about 100 full-time editors and more than 4,000 expert...
, a description of the condition raphania includes the symptom:
...a formication, or sensation as of ants or other small insects creeping on the parts.
Described again in an instructional text from 1890:
A variety of itching, often encountered in the eczema of elderly people, is formication; this is described as exactly like the crawling of myriads of animals over the skin. It is probably due to the successive irritation of nerve fibrils in the skin. At times patients who suffer from it will scarcely be persuaded that it is not due to insects. Yielding to the temptation to scratch invariably makes the disease worse.