DiseaseDisorder infobox
Name = Formication
ICD10 = ICD10|R|20|2|r|20
ICD9 = ICD9|782.0

Formication is a somewhat unusual, but medically well-known, abnormal sensation. This sensation closely resembles the feeling of insects crawling on and/or under the skin, and can also include sensations which resemble those of insects stinging or biting. There are many known causes of formication.

The word is derived etymologically from the Latin word "formica", meaning "ant", precisely because of this similarity in sensation to that of crawling insects.

Formication is a specific form of the general set of abnormal skin sensations known as paresthesia, and thus it is related to the sensation known as "pins and needles", and other tingling sensations.

Some people suffering the sensation of formication find it to be annoying, others find it painful, and some find it itchy. Those who find it to be itchy may in some cases repeatedly scratch themselves until they bleed, causing skin damage and sores. (In the subset of cases where the sufferer is delirious or intoxicated because of high fever, substance abuse, or extreme alcohol withdrawal, this repeated scratching is very common indeed.)

Formication can on occasion lead to people becoming fixated on the sensation and its possible meaning, and these people may develop delusional parasitosis. This is a situation where individuals are convinced that there are real insects crawling on and/or under their skin, whereas in reality there are no insects involved, just a crawling sensation. It is fairly easy to misunderstand the significance and causality of the "creepy crawly" sensation of formication.


Causes of formication include medical conditions such as diabetic neuropathy, skin cancer, syphillis, or herpes zoster as well as normal states such as menopause (i.e. hormone withdrawal). Formication can also sometimes be experienced during high fevers. Itching, tingling and formication ("the creeps") often occur when surfacing from a dive or during ascent to altitude (decompression sickness).

It can be a rare side effect of many prescription drugs such as Ritalin, Adderall and Lunesta.

In addition, formication can be caused by the withdrawal component of substance abuse. It is a common side-effect of the extensive use of cocaine or methamphetamine, or the abusive use of amphetamines. Extreme alcohol withdrawal may also cause symptoms of formication, along with delirium tremens, and can often be accompanied by visual hallucinations of insects.


Formication was neatly described in 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. [ [ William Allan Jamieson, "Diseases of the Skin: A Manual for Practitioners and Students", 1890] ]

The term formication has been in use for several hundred years. In the 1797 edition of the Encyclopædia Britannica, a description of the condition includes the symptom:

...a formication, or sensation as of ants or other small insects creeping on the parts. [ [ Encyclopædia Britannica] , 1797, page 260]

Depictions of formication in fiction

The novel A Scanner Darkly by Philip K Dick contains a scene where the character Jerry Fabin (and Charles Freck in the movie of the same name) suffers from formication and attempts to remedy the condition by showering for hours on end.

In the movie Old Boy, the main character experiences formication while imprisoned for 15 years.

The word formication appears in the epic David Foster Wallace's novel, Infinite Jest, when it was used in a character's description of DTs in alcohol detox.

In the movie Friday (film), Smokey (Friday) has a flashback showing him smoking a joint, while his friends tell him to take it easy. They then tell him it was angel dust. Soon Smokey experiences formication, and starts scratching his skin.


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Look at other dictionaries:

  • formication — [ fɔrmikasjɔ̃ ] n. f. • 1520, repris XIXe; lat. formicatio, de formicare « fourmiller » ♦ Méd. Vieilli Fourmillement. ⇒FORMICATION, subst. fém. Vx, MÉD. Sensation analogue à celle produite par des fourmis sur la peau. Synon. usuel fourmillement.… …   Encyclopédie Universelle

  • Formication — For mi*ca tion, n. [L. formicatio, fr. formicare to creep like an ant, to feel as if ants were crawling on one s self, fr. formica ant: cf. F. formication.] (Med.) A sensation resembling that made by the creeping of ants on the skin. Dunglison.… …   The Collaborative International Dictionary of English

  • Formication — (v. lat.), so v.w. Ameisenkriechen …   Pierer's Universal-Lexikon

  • formication — (n.) crawling sensation as of ants on the skin, 1707, from L. formicationem, noun of action from formicare to crawl like ants, from formica ant (see FORMICA (Cf. Formica) (2)) …   Etymology dictionary

  • formication — /fawr mi kay sheuhn/, n. a tactile hallucination involving the belief that something is crawling on the body or under the skin. [1700 10; < L (Pliny) formication , s. of formicatio a sensation that ants are crawling on one s skin, equiv. to… …   Universalium

  • FORMICATION — n. f. T. de Médecine Sensation d’engourdissement analogue à celle que produit le picotement des fourmis …   Dictionnaire de l'Academie Francaise, 8eme edition (1935)

  • formication — noun An abnormal skin sensation similar to that of insects crawling over or within the skin; a tactile hallucination involving such a sensation. A common side effect of substance abuse, it can also be experienced with high fever, menopause, skin… …   Wiktionary

  • formication — A form of paresthesia or tactile hallucination; a sensation as if small insects are creeping under the skin. [L. formica, ant] * * * for·mi·ca·tion .fȯr mə kā shən n an abnormal sensation resembling that made by insects creeping in or on the… …   Medical dictionary

  • formication —    see formicative hallucination …   Dictionary of Hallucinations

  • formication — (for mi ka sion) s. f. Terme de médecine. Douleur qu on a comparée à celle que produiraient des fourmis qui s agiteraient dans une partie. ÉTYMOLOGIE    Voy. formicant …   Dictionnaire de la Langue Française d'Émile Littré

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