Milia

Milia are very common, benign, keratin-filled cysts that occur in individuals of all ages, from infants to elderly persons.

• Primary milia are typically seen in infants but may also occur in children and adults.
• Secondary milia are observed in a number of blistering disorders and following dermabrasion.
• Milia en plaque and multiple eruptive milia are distinct entities.

These are tiny epidermoid cysts. The cysts may be derived from the pilosebaceous follicle. Primary milia arise on facial skin bearing vellus hair follicles. They are thought to be a manifestation of immature sebaceous glands. Secondary milia result from damage to the pilosebaceous unit. They occur spontaneously or following subepidermal blistering e.g. after burns or a blistering disease.² They have also been known to occur after potent topical steroid use.¹

• Primary milia in newborns are so common (approximately 50% of infants) as to be considered normal.
• Multiple eruptive milia and milia en plaque are rare entities.
• No racial predilection is recognised.
• Sexual prevalence is equal.

Milia are superficial, uniform, pearly-white to yellowish, domed lesions measuring 1-2 mm in diameter. They are asymptomatic.

Primary milia

Primary milia, in term infants, occur on the face, especially the cheeks, nose and eyes. In older children and adults, they also develop on the face, particularly around the eyes. They may also be found on the mucosa (Epstein pearls) and palate (Bohn nodules).¹

Secondary milia

These are found anywhere on the body where there has been a predisposing condition.

Milia en plaque

In milia en plaque, the small papules arise on a distinct, erythematous plaque in the postauricular area, unilaterally or bilaterally. Submandibular plaques and lesions on the pinna have been reported.^3,4

The clinical appearance is diagnostic in simple milia and no further investigations are required. In elderly people with sun damaged skin, a biopsy is needed to exclude nodular elastosis of the skin (Favre-Racouchet syndrome). If milia en plaque is suspected, a biopsy is prudent to exclude the differential diagnoses.

• Acne vulgaris
• Syringoma
• Trichoepithelioma
• Lichen planus follicularis tumidus
• Follicular mucinosis

Another differential diagnosis is closed comedones which are more cream than white. They also usually have a small punctum as well as being associated with open (black) comedones.

• Often no treatment is required.
• Some milia may be removed with a needle as they often shell out easily.⁵
• Topical peeling agents do not work.

Harmless but unsightly. In the infant, they tend to resolve spontaneously but in older children and adults, they may persist, requiring removal with a needle (no anaesthetic is required).¹

For confirmation of diagnosis or reassurance. It is worth referring patients with suspected milia en plaque.