Milia 1_0612 Derm Dx
Milia 2_0612 Derm Dx
A 54-year-old man presents complaining of a whitish papule on his nasal sidewall. He is uncertain how long it has been present but complains that it is embarrassing.
The patient’s past medical history is significant for renal cell carcinoma, which was treated with nephrectomy and basal cell carcinomas of the forearm, which were treated with wide local excision. What’s your diagnosis?
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A milium is a white, superficial keratinous cyst. Milia are essentially small and superficial epidermoid cysts, derived from the infundibulum of vellous hairs. Milia can appear spontaneously (primary milia), or can be due to trauma, skin disease or medications (secondary milia).
As many as half of newborns have primary congenital milia which appear on the face, scalp, superior trunk and proximal extremities. Primary congenital milia resolve spontaneously over weeks. Primary milia are also common on the face and genitalia in adults and children. These milia rarely self resolve.
Less common presentations of primary milia include multiple eruptive milia and milia en plaque. In multiple eruptive milia, large numbers of milia erupt on the head over a period of weeks. In milia en plaque, multiple milia develop overlying an erythematous plaque in the periauricular or periorbital skin.
Secondary milia develop due to trauma, skin disease or medications. Examples of trauma that could lead to milia include skin grafts, dermabrasion and chemical peels. Skin diseases implicated in milia include pemphigus vulgaris, bullous pemphigoid and herpes zoster. Medications associated with the condition include cyclosporine and long-term topical steroid therapy.
The diagnosis is made clinically by the characteristic appearance of a small white superficial cyst. When the diagnosis is in doubt, the lesion can be punctured and cyst contents expressed, thus both confirming the diagnosis and treating the lesion.
On histology milia are identical to epidermal inclusion cysts and appear as a cystic structure lined by stratified squamous epithelium filled with laminated keratinaceous material.
Treatment and prognosis
Congenital milia in infants are self-limited, so no treatment is necessary. For a limited number of lesions that occur in children and adults, puncturing the cyst with a large-gauge needle or 11-blade and expressing the cyst contents with a comedone extractor (as pictured) is quick and effective. Topical tretinoin and oral minocycline have been used to treat more widespread milia, such as milia en plaque.
Adam Rees, MD, is a graduate of the University of California Los Angeles School of Medicine and a resident in the Department of Dermatology at Baylor College of Medicine in Houston.
1. Bolognia J, Jorizzo JL and Rapini RP. “Chapter 110: Cysts.” Dermatology. St. Louis, Mo.: Mosby/Elsevier, 2008.
2. James WD, Berger TG, Elston DM et al. “Chapter 29: Epidermal Nevi, Neoplasms, and Cysts.” Andrews’ Diseases of the Skin: Clinical Dermatology. Philadelphia: Saunders Elsevier, 2006.