Formication is a form of tactile hallucination characterized by the sensation that insects are crawling on or under the skin. The name for this phenomenon is derived from the Latin word for "ant," and people may describe ants specifically or any number of insects. Additionally, this hallucination can involve non-insect life, such as worms. People who experience this form of hallucination can be treated, with a number of treatment options available, depending on the cause.
Several underlying medical issues can be linked with formication, including neuropathies, high fever, syphilis, skin cancer, and herpes zoster. In addition, people sometimes experience the condition as an adverse drug reaction, with various medications being linked with this phenomenon. People on cocaine, methamphetamine, and some other illegal drugs can also experience tactile hallucinations of this type. Other hallucinations can also accompany the sensation that insects are crawling all over the skin.
In some cases, formication leads to delusional parasitosis. The patient becomes convinced that he or she has been colonized by parasites, insisting on treatment even when a doctor can find no signs. Some patients even retain samples in small boxes or paper bags, bringing these in to the doctor and demanding that they be analyzed. Since the doctor can find nothing to treat, the patient may be sent home empty handed, in turn complaining about incompetent medical treatment, and the patient may make numerous medical appointments in an attempt to find a doctor who can find the parasites the patient is certain are present.
In addition to causing delusional parasitosis, formication can also lead to severe injuries as patients scratch at themselves in an attempt to combat the itching, crawling sensation. Patients have been known to cut at themselves during bouts of formication as well, with the goal of removing the insects or other organisms which the patient thinks are causing the sensation. This can lead to infection, especially in illegal drug users, who may be in unclean environments where infectious agents are present in abundance.
Addressing formication requires treatment of the cause. If, for example, it is being caused by medication, a change of medication can be used to resolve the hallucinations. Medications and medical procedures used to manage the itching and tingling associated with neuropathies can also be employed to treat the condition. It is important for patients to also receive treatment for cuts and scratches, and if a patient cannot stop scratching, cutting, or picking, restraints may need to be used to allow the patient's skin to heal.