How to Manage Patients With Dermatologic Delusional Disorders

Mio Nakamura, MD; John Y.M. Koo, MD


August 11, 2015

In This Article

Initiating Antipsychotic Therapy

In our experience in treating patients with dermatologic delusional disease, the best way to discuss antipsychotic therapy is by a pragmatic, "trial and error" approach. The patient's top priority is usually relief from the present torment. The historical gold standard for the treatment of delusions of parasitosis is pimozide (Orap®).[6] Pimozide has one major advantage over all other antipsychotic agents: The official US Food and Drug Administration indication is Tourette syndrome. With the wide resources now available on the Internet, patients are well aware that pimozide has no psychiatric indication, which makes it uniquely acceptable to them.

Pimozide is started at 0.5-1 mg per day and titrated upward by 0.5-1 mg every 2 weeks. It is important to tell the patient that therapeutic benefit may not be reached until the dosage is 3-5 mg per day, although a large proportion of patients experience therapeutic benefit with as little as 1 mg per day. Once the patient experiences significant improvement, the medication should not be stopped too soon. You may continue the effective dosage for at least 2-3 months before initiating a slow taper at a rate similar to uptitration.

Pimozide is very effective at a low dose, and thus side effects are rarely encountered in practice. The more common side effects are stiffness and restlessness (ie, extrapyramidal side effects), which can easily be controlled with use of over-the-counter diphenhydramine (Benadryl®) 25 mg up to four times per day as needed. If the patient has problems with the sedative side effects of diphenhydramine, benztropine (Cogentin®) 1 or 2 mg up to four times a day can be substituted. Tardive dyskinesia is a possible side effect but is rarely seen owing to the low dosage and short time course of treatment.

Alternatives to pimozide include newer antipsychotics, risperidone (Risperdal®), olanzapine (Zyprexa®), aripiprazole (Abilify®), and quetiapine (Seroquel®). The medication is slowly titrated up to the optimal dose, then maintained at that dose for 2-3 months even if symptoms are minimal or absent. It is slowly tapered off. With this regimen, it is possible to cure a large segment of these patients.

After complete remission, the recurrence of symptoms months or years later is extremely rare. Such recurrence can be effectively treated by following the same regimen outlined above.

Addressing Undertreatment

It is unfortunate that delusional conditions, which clearly have a large negative impact on a patient's life, are undertreated despite the availability of safe therapeutic options.[7] Like any other skill in our profession, once the dermatologist becomes familiar with the above art of medicine, it becomes much easier to handle these cases. Patients with delusional disease can be the most grateful patients you will ever have in your practice.


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