A severe infestation of microscopic skin mites may mimic rosacea but fail to respond to standard therapy, according to a presentation by Dr. Martin Schaller, assistant professor of dermatology at Ludwig-Maximilians University in Munich, Germany, during the annual meeting of the American Academy of Dermatology.
The tiny mites, known as Demodex folliculorum, are normal inhabitants of human skin. Studies have found an elevated incidence of Demodex in rosacea patients, but it is uncertain whether this is a contributing factor or a result of the disorder.
"Our faces are home to these mites because the number of sebaceous glands is highest there," Dr. Schaller said. He noted that a severe infestation of Demodex may cause an appearance that resembles rosacea, but there are differences that can often be detected. "In contrast to rosacea, the lesions of Demodex are often small superficial papules that appear in clusters and show an asymmetrical distribution," Dr. Schaller said. "Additionally, there is a sudden onset of symptoms with rapid progression and no history of flushing. There are also no telangiectasia (visible blood vessels), and involvement of the eyelids with demodectic blepharitis is another clue." He said the diagnosis can be confirmed with a five-minute scrape test, and the condition can be cleared by eradicating the mites rather than treating the inflammation.
Erbagci Z, Ozgoztaosi O. The significance of Demodex folliculorum density in rosacea. International Journal Dermatology. 1998;37:421-425.