A multinational panel has outlined best-practice recommendations for delusional infestation, aiming to bring greater consistency to the diagnosis and treatment of the challenging condition.
International experts have endorsed antipsychotics as first-line treatment and closer dermatology–psychiatry collaboration for delusional infestation, while remaining divided on whether patients should be explicitly told the diagnosis, according to a new Delphi consensus study.
The majority agreed that antipsychotic medication should be offered as first-line therapy and backed prescribing by appropriately trained dermatologists, recognising that many patients first present to dermatology clinics and may be reluctant to engage with psychiatric services.
The study has been published this month in the Journal of the European Academy of Dermatology & Venerology.
Delusional infestation (DI) is a psychiatric disorder defined as a fixed false belief of being infested with animate or inanimate material in the absence of objective medical evidence.
“Patients often report tactile hallucinations or abnormal skin sensations, leading to significant distress and frequent healthcare encounters involving various professionals,” the researchers wrote.
“Antipsychotic treatment remains the cornerstone of therapy, with many patients showing a positive response to treatment.
“Amisulpride and risperidone have more recently emerged as the antipsychotics with the highest efficacy in DI. However, patient engagement and adherence to therapy are often challenging, as they frequently reject psychiatric explanations for their symptoms.”
The recommendations, developed by 34 dermatology, psychiatry, and tropical medicine specialists from 13 countries under the umbrella of the European Society for Dermatology and Psychiatry, represent one of the most comprehensive attempts to standardise care for a condition that is frequently seen in dermatology clinics but remains poorly studied.
Consensus was achieved on 20 of 22 statements covering disease definition, diagnostic investigations, treatment, and communication strategies.
Experts agreed that DI should be defined as a psychiatric disorder characterised by a fixed false belief of infestation with living organisms or inanimate material despite the absence of objective medical evidence.
They also endorsed distinguishing between primary DI and secondary DI associated with psychiatric, neurological, or medical disorders, and concluded that Morgellons disease should be regarded as a subtype of DI.
The panel unanimously supported examining specimens, photographs, and other materials brought in by patients as part of the diagnostic process, both to assist assessment and to build trust.
Blood tests, urine toxicology screening, and neuroimaging were also recommended in selected cases to investigate potential underlying medical, neurological, or substance-related causes.
More than 85% of participants agreed that close collaboration between dermatologists, psychiatrists, and other specialists is essential and that treatment of psychiatric symptoms and coexisting skin disease should begin concurrently whenever possible.
Antipsychotic medication emerged as the clear treatment of choice, with more than 90% of experts agreeing it should be offered as first-line therapy.
The experts generally advised against routine use of long-acting depot antipsychotics and called for guidance on treatment duration and tapering.
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They also concluded that current evidence does not support an additional therapeutic benefit for cognitive behavioural therapy in most patients with DI.
Communication remained the most contentious issue.
While panellists agreed that clinicians may need to use alternative or adapted terminology when discussing the condition with patients who reject psychiatric explanations, only 45% supported explicitly naming the diagnosis of delusional infestation.
Many experts argued that doing so too early could damage rapport and cause patients to disengage from treatment.
The question of prescribing rights also drew varied opinions, the researchers said.
“While trained dermatologists emphasised that they were generally supported in prescribing antipsychotics by psychiatrists, some experts favoured a more flexible, interdisciplinary model, especially in regions where psychiatric services are limited,” they wrote.
“Although depot formulations are generally associated with improved treatment adherence, 75% of experts expressed concerns about their use in DI.
“These concerns were primarily related to potential side effects and the difficulty of administering long-acting injectable treatment without the patient’s full and informed agreement, which can be challenging, given the nature of the condition.
“Some experts noted, however, that depot antipsychotics may be appropriate in select cases, particularly after successful oral treatment and within the context of shared decision-making.”
However, there was strong agreement that patients must always be informed when they are prescribed an antipsychotic medication, reflecting the importance of informed consent regardless of how the diagnosis is framed.
“The findings highlight the importance of early intervention, interdisciplinary collaboration and the thoughtful use of language when engaging with patients,” the researchers wrote.
“In the absence of high-level evidence, this consensus statement provides a pragmatic, expert-informed framework to support clinicians in the effective and compassionate management of DI.
“These results lay the groundwork for future guideline development and affirm the need for ongoing research in this complex condition.”
Journal of the European Academy of Dermatology & Venerology, June 2026
