By Gary M. White, MD
This "rosacea look-alike" was unilateral, a tipoff to the diagnosis.
The Demodex mite is a common inhabitant of the skin, especially on the face in the pilosebaceous unit. Whether it actually can cause disease has been a matter of debate. One usually considers the possibility of this disease in a patient thought to have rosacea (or less commonly blepharitis) who fails to clear on standard rosacea therapy or who has unilateral lesions.
Most cases reported under the name Demodicosis have been follicular, pustular eruptions of the face. Diffuse erythema of the face may be present. Often, they resemble rosacea, but may be unilateral. A scraping of the skin viewed under oil or with added KOH readily reveals the mites. A biopsy may also be done which will show abundant mites. A Demodex folliculorum-associated spinulosus has been reported in which patients develop multiple follicular spines and may complain of a rough sandpaper feel to the skin [JAMA Derm 2015;151;1251].
At least 5 cases of patients receiving hematopoietic stem cell transplant followed by chemotherapy have developed demodicosis. The clinical presentations include confluent erythema of the face, a pruritic eruption on the cheeks and jawline and a desquamative facial eruption. These patients initially were interpreted as having acute graft vs. host disease. [JAMA Derm Dec 2013;1407].
An oral dose of ivermectin 200 ug/kg, repeated in 7 days can be very effective. Oral metronidazole 250 TID may be given as well in combination. This may be followed by weekly topical 5% permethrin, benzyl benzoate, or metronidazole BID.
The demodex mite.
"Unilateral rosacea" is a characteristic presentation.
A 7-year-old girl with pruritic grayish and yellowish crusted, scaly plaques over her nose and cheeks, along with diffuse facial erythema, papules, and pustules. Case Reports in Dermatological MedicineVolume 2014 (2014), Article ID 458046
A 28-year-old man with itchy, red, papulopustular eruptions on the central part of the face for 4 months.
Indian J Dermatol. 2012 Jan-Feb; 57(1): 72–73
Homepage | FAQs | Use of Images | Contact Dr. White