INTRODUCTION
A diagnosis of DP can be quite evident on initial presentation—patients often directly and firmly state their delusions; he or she may
bring in a plastic bag of evidence, or admit he or she has already
consulted specialists regarding an infestation. However, the diagnosis of DP is one of exclusion and thus evaluation should first focus
on ruling out medical causes of a patient's symptoms (for further information see Freudenmann et. al 2 ). A thorough investigation also
builds up the patient's trust in the physician and acknowledges
that the patient's problems are valid and worth treating. 3 While
evaluating the symptoms, it is important to avoid statements that
may hinder future treatment. When discussing any laboratory
tests with the patient, it is important not to frame them as tests for
parasites and validate the patient's delusion. Rather, frame them
as tests for their symptoms, eg, "This blood test may reveal the
cause of your itch." While it is important to not validate the delusion, contradicting the delusion will create tension between the
physician and the patient. If the patient brings in "specimens" to be examined, each item should be carefully looked at with the patient and clearly named. Again, avoid statements such as "there
is no evidence of parasites here," which directly contradict the
patient's delusion. Gaining the patient's trust during the first few
visits is crucial to treating the underlying psychiatric problem.
Discussion
DP may be associated with specific behaviors, medical problems
and psychiatric diseases. A thorough history may reveal that
the symptoms began following an episode of contact dermatitis, a true arthropod bite, starting a new medication, consuming
an illicit drug, or experiencing a recent psychosocial stressor.
Patients can induce an irritant or contact dermatitis by using disinfectants, by using insecticides or washing excessively. They
may report that they constantly itch and scratch or that they
are using metal instruments to extract the parasites from their
skin. Besides these activities which may cause skin lesions, it
is important to elicit signs of other psychiatric conditions such
as schizophrenia, paranoid states, bipolar disorder, depression,
anxiety disorders, obsessional disorders, and suicidality as these
are associated with and may cause DP.4,5 Finally, find out what
is most distressing to the patient, whether it is the itching, the
sensation of bugs crawling under their skin, the long rituals that
interfere with their functioning, or the frustration from no one
believing what they are saying.
After taking the history, examining the skin, and ordering tests, the
next step is to approach the subject of psychiatric referral with a
patient. This is a delicate process and should be done very carefully, as the rapport established thus far may be easily broken. Rather
than pointing to the negative lab results and telling the patient
that he or she must be wrong about the infestation, the subject of
psychiatric referral can instead be approached as a possible adjunctive treatment to dermatological care.5 If the patient mentions
any recent psychosocial stressors during the interview, this can
be used as a starting place to suggest that, in addition to continuing dermatologic care, he or she may want to talk to a mental
health professional about the stressful problems in his or her life,
or about the impact of the stress of these symptoms.
Another potential source of referral may be to a psychologist. Although this option is not traditionally referred to in the
dermatological literature on DP, psychological interventions have been found to be effective in reducing symptoms of
psychosis interventions
