A 60-year-old white man presents with excoriated and crusted papules and nodules on the face.Self-treatment with topicals has not offered relief. He has an unremarkable patient history. What’s your diagnosis?
Intense Pruritic Facial Eruption
By Ted Rosen, MD
Professor of Dermatology, Baylor College of Medicine, Houston, Texas
CASE HISTORY
A 60-year-old white man presented for evaluation of an intensely pruritic facial eruption. He has obtained minimal relief from neither thrice daily application of over-the-counter 1% hydrocortisone cream nor twice daily application of Sarna® lotion. Both of the foregoing maneuvers had been suggested by his primary care provider based upon a telehealth consultation during the local peak of COVID-19 cases. The patient’s past medical history was unremarkable, and he was on no medications. There was no notable travel history, although he did frequently visit the home of his brother where there were two adult cats in residence. Recent routine laboratory testing was unremarkable, with the exception of moderate lymphopenia. The latter was ascribed to an upper respiratory infection.
Physical examination revealed many excoriated and crusted papules and nodules on both cheeks; there were a small number of similar lesions on the nose, forehead, and upper neck. (Figure 1) There was one intact papulopustule on each cheek. The remainder of the cutaneous examination was unremarkable. Submental, submandibular, and cervical adenopathy was not detected. Vital signs were normal; specifically, the patient was afebrile.
The differential diagnosis included rosacea, tinea barbae, scabies, HIV infection (eosinophilic folliculitis), zoophilic ectoparasites (like chyletiella), bacterial folliculitis, and eczema (NOS). A biopsy was suggested, but the patient was reluctant to have this done on the face. Therefore, in an attempt to further define the process by ruling out some entities, the two pustules were scraped, and the contents examined under potassium hydroxide.
What Is Your Diagnosis?
DISCUSSION
Both lesions contained innumerable Demodex folliculorum. The presumptive diagnosis of papulonodular/papulopustular demodicosis was made. The patient was given a single 200 ug/kg dose of oral ivermectin and two weeks of daily application of ivermectin 1% cream. The eruption completely resolved.
However, severe facial demodicosis is typically seen in those with underlying immunocompromisation, either by disease state or by iatrogenic immunosuppression. Further history elucidated that the patient was a member of the men-who-have-sex-with-men community. He was found to be HIV-positive (previous HIV testing had been negative) with a diminished CD4+ lymphocyte count. Thus, his demodex-induced eruption was the first manifestation of HIV infection.
For Further Reading:
Ashack RJ, Frost ML, Norins AL. Papular pruritic eruption of Demodex folliculitis in patients with acquired immunodeficiency syndrome. J Am Acad Dermatol. 1989;21:306-307.
Dominey A, Rosen T, Tschen J. Papulonodular demodicidosis associated with acquired immunodeficiency syndrome. J Am Acad Dermatol. 1989;20:197-201.