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Battling bugs...that aren't there

Dermatologists embrace empathy, antipsychotics to help patients with psychocutaneous disease


Battling bugs...that aren't there

Dermatologists embrace empathy, antipsychotics to help patients with psychocutaneous disease


By Jan Bowers, contributing writer

Dermatologists are well equipped to diagnose and treat all manner of skin disorders that they can readily see or detect through dermoscopic examination or biopsy. But what about those that exist only in the patient’s mind? Delusional patients are no less tormented by the symptoms of their disease than non-delusional patients — perhaps even more so, as they often present to the dermatologist after having their concerns dismissed by other physicians. They’re also notoriously resistant to trying any of the antipsychotic drugs that have proven effective and well tolerated, say dermatologists who have treated these patients.

An article offering clinical perspectives on psychocutaneous disease noted that an estimated 30% of patients presenting to an outpatient dermatology clinic will have some type of psychiatric distress. The same article stated that among psychocutaneous disorders, delusional infestation (DI, also known as delusions of parasitosis) is the most common monosymptomatic, hypochondriacal psychosis in dermatology (J Am Acad Dermatol. 2017;5:779-91). DI patients have a “fixed, false belief that they are infested with parasites or have foreign objects extruding from their skin.” The latter belief is sometimes referred to as Morgellons disease, and often involves the perception of protruding fibers or threads; some dermatologists consider it to be a subset of DI rather than a separate disorder.

Four experts in the treatment of psychocutaneous disease discussed the unique challenges and rewards in treating patients who are suffering from a disorder that exists at the intersection of dermatology and psychiatry. 

Diagnosing primary DI

A recent JAAD article that focused on the diagnosis and management of DI described the criteria listed in the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (2019;5:1428-34) as necessary for a diagnosis of primary DI:

• The presence of a delusion for at least one month where the criteria for schizophrenia have not been met;

• The patient is functioning in general outside of the delusion of parasitosis;

• Mood episodes have been brief relative to the duration of the delusional period(s);

• The disturbance is not attributable to medical conditions, substances, or another disorder.

Determining a diagnosis can be extremely difficult if the initial visit is brief, said Michelle Magid, MD, associate professor of psychiatry at the University of Texas Dell Medical School. Dr. Magid co-directed, with dermatologist George Kroumpouzos, MD, PhD, a session on psychocutaneous disease at the AAD 2019 Annual Meeting. In fact, when DI is suspected, many dermatologists will schedule the patient for the end of the day and plan for multiple visits. “Accurately assessing whether a patient has a psychiatric disorder usually requires an extensive interview, which the dermatologist simply can’t do in a 10-minute time slot,” she remarked. “So the most important thing is to look for key points in distinguishing whether or not the patient has delusional infestation or something bigger such as schizophrenia or bipolar disorder.”

Patients with schizophrenia “may have other delusions, not just the one about infestation. They’ll also present with disorganized thinking, speech, and behaviors. They may hear voices; they may be isolating themselves and not taking care of basic activities of daily living, such as showering.” If the dermatologist suspects schizophrenia, they should gently question the patient, Dr. Magid suggested. “‘Do you hold any other beliefs that other people might think are strange?’” Or, “‘Sometimes when people are distressed, as I can see that you are, they may hear voices. Do you hear voices?’ And ‘what do they tell you?’” In a patient with bipolar disorder, the delusion of infestation may come with manic episodes and then wane, Dr. Magid explained.

If a psychiatric co-morbidity is revealed? “In an ideal world, a dermatologist should not be managing these patients,” said Dr. Magid. “But that said, I know many dedicated dermatologists who do manage their patients’ mental illness, either because the patient refuses to see a psychiatrist or because of the lack of access to a psychiatrist, especially in rural areas.”

One hallmark of DI is the “matchbox sign,” which refers to the common practice of patients bringing in skin scrapings which they believe will contain evidence of parasites. Another is the patient’s demand for a biopsy, also to validate their belief that an infestation is present. Examining the specimens and performing a biopsy can both be helpful in ruling out actual infestation, but both procedures should be approached with the idiosyncrasies of the DI patient in mind, said Mio Nakamura, MD, a second-year resident in dermatology at the University of Michigan. “Probably 90% of these patients bring in a specimen to show; usually they’re just clothing fibers, dirt, or lint. It’s really hard to know what’s going on, so I ask them to bring it back on a microscopic slide — I give them a set of glass slides — and when they bring it back I actually do look at it under the microscope. Mostly it’s helpful in building a rapport with these patients, to show you’re interested.” For patients who insist on a biopsy, Dr. Nakamura tries to strike a bargain: one and only one biopsy, at a site of the patient’s choosing. “Then we say, if this doesn’t show bugs, or it doesn’t tell us what you want it to, you need to be open to hearing us out on what treatments we might have for this condition.”

Building a rapport

Managing a patient with primary DI can require a delicate balancing act between acknowledging the patient’s symptoms and not reinforcing their delusional beliefs. “The patients who come to see us have been to everyone,” said Dr. Nakamura. “They’ve been to the emergency room, their primary doctor, numerous other dermatologists. If you’re not trained in delusions of parasitosis, a lot of doctors, especially in the ED or primary care, can think the patient is just crazy and dismiss them. So they start looking for another doctor.”

John Y.M. Koo, MD, with whom Dr. Nakamura trained as a clinical research fellow, said the three most important qualities in the management of DI patients are “empathy, empathy, and empathy.” Dr. Koo, who is a professor of dermatology at the University of California, San Francisco Medical Center and is board-certified in dermatology and psychiatry, noted that “physicians are usually at the center of respect and affection — everyone revolves around you — but when you’re dealing with someone who is delusional, within reason you have to revolve around that person’s thinking. It takes a change on your part to interact with delusional patients without looking down on them or taking their negative comments personally. People with primary DI are generally very nice, sensitive, polite people — except when they talk about their delusion.” Angering a patient by challenging their delusion can have severe repercussions, Dr. Koo warned. “If you anger a delusional patient, despite the fact that you did everything right from the conventional perspective, some of them will go out of their way to destroy your patient satisfaction score. That affects every patient you see. An even bigger problem is that if you don’t connect with these people, they won’t fill a prescription or be compliant with medicine.”

Once due diligence has ruled out other causes, Dr. Koo signals to the patient that it’s time to switch “from investigation to therapy. I deliberately articulate their misery in front of them: ‘This is a living hell.’ Many of them really appreciate that because I’m finally recognizing that this is serious, whereas other doctors have told them they have nothing to worry about.” Dirk M. Elston, MD, co-author of the recent JAAD article on the diagnosis and management of DI, recommends a similar approach. In a Q&A with DW physician editor Kathryn Schwarzenberger, MD, (April 1, 2019), Dr. Elston, who is professor and chair of the department of dermatology and dermatologic surgery at the Medical University of South Carolina, remarked that “confrontation does little to help the patient and ruins my day in clinic. It is generally better to develop a supportive doctor-patient relationship with the patient and stress that you are trying to focus on relieving their symptoms.”

Drug testing the DI patient

A number of drugs — prescription, over the counter, and illicit — can mimic the symptoms of delusional infestation (DI). Topping the list of 17 such substances cited in a review article about the disorder are amphetamines, methamphetamines, cocaine (including crack), tetrahydrocannabinol (THC), and alcohol (Int J Dermatol. 2013; 52: 775-83). In the medical literature, dermatologists are routinely advised to rule out substance use or abuse as a cause of the delusions before arriving at a diagnosis of DI. However, in practice, deciding whether, and how, to approach the patient about getting a drug screen can be difficult.

“Theoretically, it would be good to do it on everyone. However, the more you see these patients, the more you appreciate the reality, which is that most hate the idea that they’re seen as crazy, and they also hate the implication that they’re experiencing these symptoms because they’re drug abusers,” said John Y.M. Koo, MD. “Before I broach the subject of whether to test for drugs, I have to use my judgement about risk versus benefit. If a patient is already complaining bitterly about how previous dermatologists dismissed their concern, or implied they’re crazy or druggies, obviously it’s better not to say to them, ‘Oh, by the way, I want to test you for drugs too.’” After 35 years of practicing psychodermatology, Dr. Koo maintained that he’s developed a good sense of which patients have primary DI and which are experiencing symptoms due to another underlying cause. “If it’s secondary, I don’t think dermatology is the best setting for those people,” he said. “If this is a result of drug use, what they really need is detox. I can say to them, ‘I’m very interested in your parasites, but I’m also concerned about your other problem,’ whether that’s a brain injury, schizophrenia, depression, or drug use. ‘I’d like to help you get connected with a specialist for these other things.’”

In a conversation with DW physician editor Kathryn Schwarzenberger, MD, Dirk M. Elston, MD, remarked that in his experience, “many patients will tell you what they are using if you ask the question. The key is to ask.” Drug screens can be performed at the same time as a screen for organic disease, he added, “but the discussion with the patient may be difficult. I don’t do it routinely.” Mio Nakamura, MD, who trained with Dr. Koo, said she focuses on building rapport during the patient’s first visit, but on the second or third, if she suspects drug abuse, she may say, “I have to know everything about you in order to help you. If there’s anything you’re doing, tell me now. It’s nothing you’ll get in trouble for, but it will help me help you.” In her experience, once the dermatologist has a solid rapport, patients are likely to confess to using drugs.

Psychiatrist Michelle Magid, MD, takes issue with the notion that DI patients who abuse drugs will usually be forthcoming about their drug use, and feels strongly that a drug screen should routinely be performed as part of a thorough workup. “Some patients may disclose that they smoked cannabis, and you think they’re being upfront and there’s no need to do a drug screen,” she said. “But what they’re not disclosing is that they smoke six times a day and it’s laced with cocaine.” When Dr. Magid sees a patient with DI who is using drugs, the culprit is usually cocaine, amphetamines, opiates, or cannabis, she said. “As a psychiatrist, I prescribe amphetamines, and I have seen DI occur even at standard-of-care doses,” she noted. “There does seem to be some dose dependence, with higher doses leading to a higher likelihood of DI.”

The challenge to the dermatologist is not only getting the patient to agree to a drug screen, which is necessary before proceeding, but also getting insurance to pay for it, Dr. Magid said. “For payment, you need appropriate diagnoses, and those differ from state to state.” While admitting that it may be difficult to help a drug-abusing patient who refuses a drug screen, Dr. Magid suggested framing the test as a way to rule out a problem the patient might not be aware of. “I did have a patient who was smoking cannabis that was laced with something that was caught in the drug screen, and they were not aware of it,” she noted. “It’s a way to reduce judgement and shame and questioning of the patient. However, every patient should get one, and only one, good workup, and a drug screen should absolutely be part of it.”

Therapy that works

Fortunately for patients with DI, several antipsychotic medications have proven effective against the disorder at low doses, with a clinical response rate ranging from 50% to 100%, according to the 2019 JAAD article. Unfortunately, few dermatologists prescribe them and even fewer are comfortable doing so, according to a survey of 59 dermatologists at Massachusetts General Hospital and Brigham and Women’s Hospital (J Am Acad Dermatol. 2013;68(1):47-52). Only 31% of dermatologists reported using antipsychotics in practice, and only 3% said they were comfortable prescribing this class of medication. The survey also found that while 80% reported that they’re comfortable in diagnosing DI, only 27% felt they’re successful in treating it.

Pimozide has the longest history of use and was traditionally the first-line agent for DI, but many dermatologists have turned to a newer generation of antipsychotics with superior safety profiles. These agents include risperidone, aripriprazole, and olanzapine. Dr. Koo said he still uses pimozide first “because it really works well, is well known, and has been used for decades. But the biggest reason is that pimozide is not officially an antipsychotic, and it’s the only one that is not. The only FDA indication is for Tourette’s syndrome.” Patients are very likely to perform a Google search for their medications, Dr. Koo maintained, and “as soon as they see that a drug is antipsychotic, it takes so much energy to reassure the patient and convince them to try it, and sometimes they are so angry they don’t want to try it.” Admitting that pimozide appears to have a higher risk profile than the newer drugs, “the reality is that the medicine works so well that the dose I need to turn these people around is very low. After 35 years I’m still waiting for my first EKG change.”

In contrast, Dr. Magid said she’s a fan of the newer antipsychotics, particularly aripiprazole and risperidone. “In Europe, they’re using a ton of risperidone. I like aripiprazole because it tends to have fewer anticholinergic side effects, and also causes a little bit less weight gain than some of the others. At the end of the day, it doesn’t really matter which agent the doctor decides to go with, but I would recommend that every doctor get comfortable with one agent.” In the DW article, Dr. Elston expressed a preference for risperidone, based on published data on efficacy and side effects. “Although aripriprazole has the lowest side-effect profile of the [newer] antipsychotics, it also has the least amount of evidence supporting its use in this condition. It may be a reasonable alternative if patients are very concerned about the weight gain associated with risperidone.”

Both Dr. Koo and Dr. Elston begin with a dose of 0.5mg of pimozide and risperidone, respectively. Dr. Koo increases the dosage by 0.5mg every two to four weeks, “and the dose I need to turn people around is typically 3mg per day or less. I ask them to continue for another three months, because discontinuing too soon can cause recurrence, and then we taper the medication down at the same rate as we increased it. Then most of them are fine forever. I have only had five patients with one recurrence in 35 years, and we repeated the treatment.” Dr. Elston said he gradually increases the dose of risperidone until it reaches 4mg per day.

Education essential

When Dr. Nakamura completed her fellowship with Dr. Koo and became a resident at the University of Michigan, she discovered that “no one here was prescribing antipsychotics. I asked Dr. Koo to come and speak at one of our department grand rounds. He talked about how to prescribe pimozide and other drugs, and now there are several of our faculty who are comfortable prescribing it. We prescribe a lot of immunosuppressants that are way scarier than pimozide. I think the barrier is that people just don’t know about it.” Dr. Koo called the lack of education about psychodermatology “a huge problem. We have more than 100 residency programs, and practically none of them has anyone on faculty who is published and knowledgeable about how to deal with these conditions. While they’re not as common as psoriasis or eczema, every practitioner will have to face them someday.” As a practical matter, the handful of psychodermatology experts in the U.S. probably can’t reach every dermatologist and resident through lectures, Dr. Koo noted, but if one of the psychodermatology clinics were to “hold a half-day symposium, record it, and make it available for our specialty, that could be useful.”

Dr. Magid urged dermatologists to see themselves as the first line of defense for patients with DI, because “they won’t come to me, a psychiatrist. You have a choice: Do I treat this patient even though my psychiatric training is less than ideal, and something may go wrong? Or do I not treat, and the patient never gets treatment because there’s no alternative? You may be the only potential help for this patient.”