Rare facial dermatological lesions associated with Demodex infection, besides acne vulgaris

I have read with great interest the recent article “A meta-analysis of association between acne vulgaris and Demodex infestation” by Zhao et al. (2012), published in Journal of Zhejiang University-SCIENCE B (Biomedicine & Biotechnology) (another two articles by Zhao et al. (2011a; 2011b) are also related to Demodex infestation). The article is highly thought provoking. Interestingly, Demodex infestation may be associated with a number of other facial dermatological lesions besides acne vulgaris.

For instance, Demodex infestation may cause blepharitis (Kosik-Bogacka et al., 2012). While Demodex mites can by themselves cause blepharitis, in some cases they may act as carriers of bacteria such as Bacillus oleronius which in turn may play the primary pathogenic role in the development of blepharitis (Szkaradkiewicz et al., 2011). Demodex blepharitis is also more common in diabetics. In fact, in one recent study the prevalence of Demodex blepharitis in diabetic patients was as high as 54.8% (Yamashita et al., 2011). A higher prevalence rate (as high as 4%) is also seen in human immunodeficiency virus (HIV) patients (Annam et al., 2010). A highly effective treatment of Demodex blepharitis is ivermectin administered by the oral route (Filho et al., 2011).

Demodex infestation can also play an etiopathogenic role in the development of acne rosacea as well as pityriasis rosea (Forton, 2012). Demodex infection can also result in primary irritation dermatitis as well as scalp folliculitis and seborrheic dermatitis (Karincaoglu et al., 2009). Demodex infection may present in rare cases as “pseudozoster” (Karincaoglu et al., 2008). This is commonly seen after prolonged application of topical steroids. Demodex infestation may also rarely cause sebaceous adenomas (Dhingra et al., 2009).

Physicians should be aware of these rare dermatological rashes and their close associations with Demodex infections.