Perioral Demodex folliculitis masquerading as perioral derma
This article has been published in JAAD case reports.

A healthy 33-year-old pregnant woman presented previously for peri-alar seborrheic dermatitis that responded quickly to topical hydrocortisone 2.5% cream. At 36 weeks' gestation, she noted a worsening of her skin condition, despite continued hydrocortisone use. At this time, the patient presented with papules and pustules located periorally, in the absence of comedones, consistent with a diagnosis of perioral dermatitis.

Her skin condition worsened despite stopping topical steroids and instituting topical calcineurin inhibitors, ketoconazole, azelaic acid, and metronidazole sequentially. Given the pregnancy, no tetracycline class antibiotics were prescribed.

At a follow-up visit 2 weeks later, several days after her delivery of a healthy, full-term infant, her eruption evolved into perioral and lip erythema, swelling, confluent pustules, and scaling, with pronounced pruritus and burning sensations. Notably, there was sparing of the remainder of the face and neck. A differential diagnosis at this time included allergic contact dermatitis and lip licker's dermatitis, although the clinical findings of pustules mitigated against these, and the patient lacked a history of new facial cosmetic products or propensity for lip licking.

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