CLINICAL HISTORY:

Signs and symptoms:  A 65-year-old Caucasian female with a four-year history of sores that started on the face after shingles. The sores have enlarged over the past few years and she feels the disease is spreading down towards the chest. As a retired physician, she has done excisional biopsies on herself and admits to using a scalpel on a regular basis to incise and drain the lesions, which gives her immense relief from the pressure of the lesions. She describes white tendon-like larvae and botfly-like larvae that come out and wrap around her scalpel.

Previous Treatment:  None

Other information:  Patient has traveled to South America several times for holiday and is concerned about having contracted a tropical parasite infection. Other medical history is significant for a brain tumor removed in 1992 and Alzheimer’s dementia. Patient denies tobacco, ETOH, and recreational drug use. NKDA. Medications include Synthroid, Aricept, Namenda, and Adderall. Unremarkable family history. Patient has been lost to follow-up for further information about the history and nature of the brain tumor and for re-testing abnormal lab values as listed below.

PHYSICAL EXAM:

Physical exam revealed a well-nourished, 65-year-old white female with appropriate affect. Examination of the skin reveals a large 7 x 3 cm ulcer with central black eschar and surrounding scar tissue on the right upper mid forehead. There were two similar 4 mm ulcers surrounded with atrophic scarring on the nasal tip and left alar groove with partial destruction of the right anterior alar rim, which resulted from her scalpel use. On the mentum was a 6 cm patch of erythema with edema and numerous linear excoriations. There was no lymphadenopathy.

Patient with several ulcers and excoriations on her face.

Two 4mm ulcers on the nasal tip and left alar groove and excoriations due to scalpel trauma on the chin.

excoriations due to scalpel trauma of the mentum.

LABORATORY TESTS:

Bacterial culture of the forehead was positive for light growth of coagulase negative staphylococcus species, culture of the nose was positive for growth of normal skin flora.

CBC within normal limits except for red cell distribution width 18.9% (normal 11.7-15%).

Serum Immunoglobulin G low at 607 (normal 700-1,600 mg/dL)
IgG, Subclass 1 low at 421 (normal 422-1,292 mg/dL)
IgG Subclass 2 within normal limits
IgG Sublcass 3 low at 26 (normal 41-129 mg/dL)
IgG Subclass 4 within normal limits

CMP and C-Reactive Protein within normal limits

TSH elevated at 11.59 (normal 0.45-4.5 uIU/mL)

Lipid panel within normal limits, except for slight elevation of total cholesterol 218 (normal 100-199 mg/dL)

DERMATOHISTOPATHOLOGY:

In the superficial dermis there is a perivascular and interstitial inflammatory cell infiltrate composed of lymphocytes admixed with eosinophils.

DIFFERENTIAL DIAGNOSIS:

1.   Trigeminal Trophic Syndrome
2.   Delusions of Parasitosis
3.   Herpetic reactivation and ulceration
4.   Leprous Trigeminal Neuritis
5.   Infectious- Miasis, syphilis, deep mycosis, parasite

SCROLL DOWN FOR ANSWER AND DISCUSSION.

CORRECT DIAGNOSIS:

Delusions of Parasitosis

DISCUSSION:

Patients with delusions of parasitosis have a fixed, yet false belief of being infected with parasites. They typically appear in the dermatologist’s office anxious and overwhelmed with a history of visits to multiple physicians. It is important for the physician faced with this patient to listen and be compassionate, yet not to reinforce their delusional ideology.
This disease, known as a monosymptomatic hypochondrial psychosis, has a female to male predominance of 2:1 and the mean age of symptom onset appears in the sixth decade of life. Patients often present with the “matchbox sign”, in which they have gathered specimens of parasites they have collected and want to have examined. Patients may resort to self-mutilation to rid themselves of these parasites, which may result in mild excoriations to large ulcers.
The appearance of the ulcers mimics many other disease entities such as granulomatous disease, neoplasms, vasculitis, infection, and factitial dermatitis. A thorough skin exam must be performed to rule out any organic causes for the patient’s symptoms such as nutritional disorders, neurologic disorders, substance abuse, endocrine disorders, malignancy, and infectious disease. Skin scraping and skin biopsy can be performed to confirm a certain diagnosis when indicated. To break the cycle of tactile sensation leading to destruction, the ultimate treatment is to prescribe an antipsychotic medication. Most importantly, patients must be educated as to the cause of their condition and the importance of controlling their behavior.

TREATMENT:

Treatment for delusions of parasitosis is multi-faceted and is tailored to the patient and how receptive they are in their understanding of their condition. It is important to address the wounds and prescribe a topical antibiotic or ulcer treatment under occlusion (in our case, Biafine Topical Emulsion BID) in order to prevent further infection. Further, systemic medications may be considered for symptom relief. However, since the condition has an underlying psychiatric component, the recommended therapy is treatment with anti-psychotics. Traditionally pimozide, a powerful antipruritic acting on opioid pathways, was used but has fallen out of favor due to the extrapyramidal symptoms. Currently, it is recommended to use risperidone or olanzapine, which are tolerated better by patients.

REFERENCES:

1. Zomer SF, De Wit Rf, et al. Delusions of parasitosis: a psychiatric disorder to be treated by dermatologists? An analysis of 33 patients. Br J Dermatol 1998; 138: 1030-1032.

2. Sandoz A, LoPiccolo M, et al. A clinical paradigm of delusion of parasitosis. JAAD 2008;59:6798-704.

3. Koo JY, Pham CT. Psychodermatology: Practical Guidelines on Pharmacotherapy. Arch Dermatol 1992; 128: 381-388

4. Sadeghi P, Papay FA, et al. Trigmeinal Trophic Syndrome-Report of Four Cases and Review of the Literature. Dermatol Surg 2004; 30: 807-12.

5. Sanches NB, Martin MT, et al. Ala Nasal Reconstruction in Trigeminal Trophic Syndrome. Dermatol Surg 2008; 34: 1397-1403.

6. Elmer KB, George RM, et al. Theraeutic update: Use of risperidone for the treatment of monosymptomatic hypochondrial psychosis. JAAD 2000;43: 683-686.

7. Meehan WJ, Badreshia S, et al. Successful Treatment of Delusions of Parasitosis with Olanzapine. Arch Dermatol 2006; 142: 352-5.

Additional Comment:

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