Patients labeled with delusions of parasitosis compose a heterogenous group: a retrospective study from a referral center.

BACKGROUND: There are few diagnostic tools available to the dermatologist to help in the diagnosis of patients with delusions of parasitosis (DOP). OBJECTIVE: We sought to find differences in presentation and clinical course between patients who received a final diagnosis of DOP and those who received a final diagnosis of a primary medical condition or other psychiatric disorder. METHODS: We performed a retrospective chart review of patients referred with a diagnosis of DOP. Each patient received a final consensus diagnosis. RESULTS: In all, 47 patients were included in the study. Patients reporting bugs were more likely to be given a final diagnosis of delusional disorder or found to have a medical diagnosis, whereas patients noting fibers were more likely to have a somatoform disorder. A review of systems can be helpful in making a final diagnosis. Patients referred to the clinic for DOP were 300 times more likely to require a physician to contact the hospital's legal counsel compared with other patients in the practice. LIMITATIONS: The retrospective nature of the study resulted in limited laboratory testing and psychiatric evaluation in some patients. Many of the patients may have been inappropriately referred to the DOP clinic because of other psychiatric comorbidities. CONCLUSION: Patients referred to this practice as "delusional" had a heterogeneous final diagnosis. The chief symptom of the patient was predictive of the patient's final diagnosis. The use of written questionnaires may be helpful. These patients have a greatly increased risk of requiring the physician to seek legal counsel.

Acute methotrexate toxicity seen as plaque psoriasis ulceration and necrosis: A diagnostic clue.

In addition to the well-known signs of methotrexate toxicity, rare cutaneous side effects have been described. These cutaneous signs may provide a diagnostic clue into the diagnosis of toxicity as well as facilitate early and aggressive therapy. We describe the case of a 37-year-old male, with a diagnosis of psoriasis, who developed characteristic signs and symptoms of acute methotrexate toxicity after receiving an unknown amount of intravenous methotrexate. The patient experienced a distinct change in the morphology of his existing psoriatic plaques, which became ulcerated and necrotic in the week following the methotrexate injection. Shortly after the development of cutaneous erosions, the patient developed pancytopenia, which ultimately led to his death. Ulceration and necrosis of cutaneous psoriasis plaques may serve as a herald for the impending development of life-threatening pancytopenia in patients with acute methotrexate toxicity.