Possibilities of confusion

Animals that do not exist can also occur as hallucinations (sensory disturbances) in certain diseases and not least in relation to drug poisoning (especially narcotics) and alcohol poisoning. Fear of actual animals may appear in different ways (hypochondria, phobia and hysteria), which may contain parts of the symptom complex of the person with delusional parasitosis

What to do

If you are consulted by a person with delusional parasitosis you should take the time to talk to them for two reasons.

Firstly, it is possible to have assessed the situation incorrectly at first glance and then during the conversation information can emerge, suggesting that real animals might be involved. If there is any doubt whatsoever about whether the animals could exist, it may be worthwhile to consult an interested zoologist.

Secondly, easier cases may happen where the person feels comforted by having been taken seriously and by reassurance that there is no cause for anxiety.

Control. Do not confirm the sick in the delusions by – against better judgment – suggesting treatments that kill “the animals”. This kind of control will put the consultant in a weak position afterwards. The GP of the person with delusional parasitosis is the key person. The physician may choose to treat the patient or refer to a specialist in skin diseases. In recent years, delusional parasitosis has been successfully treated with antipsychotic medication.

Animals that do not exist

Out of around 15,000 annual inquiries to the Danish Pest Infestation Laboratory, about fifty were about animals that do not exist. Among these, in particular delusional parasitosis is the one to dominate. People with this disease are convinced that they are haunted by troublesome animals (which other people cannot see or make probable). Doctors call delusional parasitosis, or imaginary animals, a monosymptomatic psychosis – i.e. a real mental illness with a single prominent symptom. The disease may occur alone or be part of other diseases.

It is part of the disease that the patients are very persistent in their efforts to get rid of their animals and often have a history of many unsuccessful inquiries to physicians, zoologists, public authorities, etc. on their problem. Their reactions in this area are understandable enough, but the animals they want help controlling do not exist.