eMedicine Specialties > Dermatology > Benign Neoplasms

Milia

Susan Cooper, MB, ChB, MD, MRCGP, MRCP, Consultant Dermatologist and Honorary Senior Clinical Lecturer, Department of Dermatology, Churchill Hospital, Oxford, United Kingdom

Updated: Sep 23, 2009

Introduction

Background

Milia are very common, benign, keratin-filled cysts. Primary milia are typically seen in infants but also may 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.

Pathophysiology

Milia are tiny epidermoid cysts. The cysts may be derived from the pilosebaceous follicle. Primary milia arise on facial skin bearing vellus hair follicles. Secondary milia result from damage to the pilosebaceous unit.

Frequency

United States

Primary milia in newborns are so common that they can be considered normal (occurring in approximately half of all infants). Multiple eruptive milia and milia en plaque are rare entities.

Race

No racial predilection is recognized for milia.

Sex

Sexual prevalence is equal for primary and secondary milia. Eruptive milia and milia en plaque occur more frequently in women.

Age

Milia occur in persons of all ages but are typically found in infants.

Clinical

History

Milia are asymptomatic. In children and adults, they usually arise around the eye. Eruptive milia, as the name suggests, have a rapid onset, often within a few weeks.

Physical

Skin lesions
- Milia are superficial, uniform, pearly white to yellowish, domed lesions measuring 1-2 mm in diameter.
- In milia en plaque, multiple milia arise on an erythematous plaque.¹
Skin distribution
- Primary milia, in term infants, occur on the face, especially the nose. They also may be found on the mucosa (Epstein pearls) and palate (Bohn nodules).
- Primary milia in older children and adults develop on the face, particularly around the eyes.²
- Milia have been observed to occur in a transverse, linear distribution along the nasal groove in some children and around the areolae.^3,4
- Secondary milia are found anywhere on the body at the sites affected by the predisposing condition.
- Eruptive milia occur on the head, neck, and upper body.⁵
- Milia en plaque manifests as distinct plaques on the head and neck. Plaques have been described in the postauricular area, unilaterally or bilaterally, the cheeks, the submandibular plaques, and on the pinna.^6,7 A linear distribution has been described.⁸

Causes

Primary milia are believed to arise in sebaceous glands that are not fully developed, explaining the high prevalence in newborn infants.
Secondary lesions arise following blistering or trauma due to disruption of the sweat ducts. Milia have been described in association with many disorders, including bullous pemphigoid, inherited and acquired epidermolysis bullosa, bullous lichen planus, porphyria cutanea tarda, and burns. Skin trauma from dermabrasion or radiotherapy can result in milia formation.
Secondary milia have arisen after contact dermatitis. They have also arisen following treatment of cutaneous leishmaniasis⁹ and after topical nitrogen mustard ointment for plaque stage mycosis fungoides.¹⁰
Secondary milia have been described following potent topical corticosteroid use.¹¹
Milia are a feature of a number of very rare genodermatoses (eg, Bazex-Dupr é -Christol syndrome).¹² Both primary milia and multiple eruptive milia have been reported as familial disorders with autosomal dominant inheritance.^13,14
The etiology of milia en plaque is unknown. One case has been induced by sorafenib, a multitargeted kinase inhibitor.¹⁵

Differential Diagnoses

Acne Vulgaris
Syringoma
Trichoepithelioma

Workup

Laboratory Studies

No investigations are needed for simple milia. The clinical appearance is diagnostic.
Investigation of the underlying disease is necessary in persons with secondary milia.

Procedures

Performing a skin biopsy is necessary only if the diagnosis is in doubt.
- If milia en plaque is suspected, performing a biopsy is prudent to exclude follicular mucinosis and multiple trichoepitheliomata.
- In an elderly person with sun-damaged skin, Favre-Racouchet syndrome (nodular elastosis of the skin) needs to be excluded.

Histologic Findings

The histological features are identical to those of epidermoid cysts, but the cysts are much smaller. The milium is usually located in the superficial dermis and has a complete epithelial lining (with a granular cell layer). It contains a variable amount of lamellated keratin. The common primary milia in infants and children are found in the undifferentiated sebaceous hair collar surrounding vellus hair follicles. Milia secondary to blistering are often found in eccrine sweat ducts.

Treatment

Medical Care

No topical or systemic medications are effective on primary and secondary milia. Single case reports have demonstrated the success of topical isotretinoin¹⁶ and tretinoin, oral etretinate,¹⁷ and minocycline in treating patients with milia en plaque.

Surgical Care

Milia can be safely left alone, but if the patient requests treatment, then incision with a cutting-edge needle and manual expression of the contents are effective.¹⁸ This can be performed without local anesthetic. A paper clip has been successfully used to express the contents of the cyst.¹⁹

Milia en plaque has been treated effectively with electrodesiccation, carbon dioxide laser,²⁰ dermabrasion,²¹ and cryosurgery.²²

Follow-up

Complications

No systemic complications have been reported.

Prognosis

Milia seen in infancy tend to spontaneously disappear within the first few weeks of life.
Milia in older children and adults tend to persist.
Secondary milia arising from blisters rarely resolve.

Patient Education

Patients or their parents can be taught how to treat milia with a needle (see Treatment).

Miscellaneous

Medicolegal Pitfalls

No significant medicolegal pitfalls are associated with this condition.

References

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Ratnavel RC, Handfield-Jones SE, Norris PG. Milia restricted to the eyelids. Clin Exp Dermatol. Mar 1995;20(2):153-4. [Medline].
Akinduro OM, Burge SM. Congenital milia in the nasal groove. Br J Dermatol. Jun 1994;130(6):800. [Medline].
Berk DR, Bayliss SJ. Milium of the areola: a novel regional variant of primary milia. Pediatr Dermatol. Jul-Aug 2009;26(4):485-6. [Medline].
Langley RG, Walsh NM, Ross JB. Multiple eruptive milia: report of a case, review of the literature, and a classification. J Am Acad Dermatol. Aug 1997;37(2 Pt 2):353-6. [Medline].
Garcia Sanchez MS, Gomez Centeno P, Rosen E, Sanchez-Aguilar D, Fernandez-Redondo V, Toribio J. Milia en plaque in a bilateral submandibular distribution. Clin Exp Dermatol. Sep 1998;23(5):227-9. [Medline].
Calabrese P, Pellicano R, Lomuto M, Castelvetere M. Milia en plaque. J Eur Acad Dermatol Venereol. Mar 1999;12(2):195-6. [Medline].
Kautz O, Muller S, Braun-Falco M, Nashan D. Milia en plaque in a linear pattern. J Eur Acad Dermatol Venereol. Feb 27 2009;[Medline].
Del Giudice P. Milia and cutaneous leishmaniasis. Br J Dermatol. May 2007;156(5):1088. [Medline].
Kalayciyan A, Oguz O, Demirkesen C, Serdaroglu S, Kotogyan A. Milia in regressing plaques of mycosis fungoides: provoked by topical nitrogen mustard or not?. Int J Dermatol. Dec 2004;43(12):953-6. [Medline].
Iacobelli D, Hashimoto K, Kato I, Ito M, Suzuki Y. Clobetasol-induced milia. J Am Acad Dermatol. Aug 1989;21(2 Pt 1):215-7. [Medline].
Berk DR, Bayliss SJ. Milia: a review and classification. J Am Acad Dermatol. Dec 2008;59(6):1050-63. [Medline].
Rutter KJ, Judge MR. Profuse congenital milia in a family. Pediatr Dermatol. Jan-Feb 2009;26(1):62-4. [Medline].
Heard MG, Horton WH, Hambrick GW Jr. The familial occurrence of multiple eruptive milia. Birth Defects Orig Artic Ser. Jun 1971;7(8):333-7. [Medline].
Chappell JA, Burkemper NM, Semchyshyn N. Localized dyskeratotic plaque with milia associated with sorafenib. J Drugs Dermatol. Jun 2009;8(6):573-6. [Medline].
Connelly T. Eruptive milia and rapid response to topical tretinoin. Arch Dermatol. Jun 2008;144(6):816-7. [Medline].
Ishiura N, Komine M, Kadono T, Kikuchi K, Tamaki K. A case of milia en plaque successfully treated with oral etretinate. Br J Dermatol. Dec 2007;157(6):1287-9. [Medline].
Thami GP, Kaur S, Kanwar AJ. Surgical Pearl: Enucleation of milia with a disposable hypodermic needle. J Am Acad Dermatol. Oct 2002;47(4):602-3. [Medline].
George DE, Wasko CA, Hsu S. Surgical pearl: evacuation of milia with a paper clip. J Am Acad Dermatol. Feb 2006;54(2):326. [Medline].
Sandhu K, Gupta S, Handa S. CO2 laser therapy for Milia en plaque. J Dermatolog Treat. Dec 2003;14(4):253-5. [Medline].
van Lynden-van Nes AM, der Kinderen DJ. Milia en plaque successfully treated by dermabrasion. Dermatol Surg. Oct 2005;31(10):1359-62, discussion 1362. [Medline].
Noto G, Dawber R. Milia en plaque: treatment with open spray cryosurgery. Acta Derm Venereol. Oct-Nov 2001;81(5):370-1. [Medline].

Keywords

milia, blistering disorders, milia en plaque, multiple eruptive milia, newborn skin lesions, infant skin lesions, infant plaques, epidermoid cysts, keratin-filled cysts, primary milia, secondary milia, dermabrasion, Epstein pearls, bullous pemphigoid, inherited epidermolysis bullosa, acquired epidermolysis bullosa, bullous lichen planus, porphyria cutanea tarda, burns, radiotherapy, blistering contact dermatitis, photocontact allergy to sunscreen, mycosis fungoides, genodermatosis

Contributor Information and Disclosures

Author

Susan Cooper, MB, ChB, MD, MRCGP, MRCP, Consultant Dermatologist and Honorary Senior Clinical Lecturer, Department of Dermatology, Churchill Hospital, Oxford, United Kingdom
Susan Cooper, MB, ChB, MD, MRCGP, MRCP is a member of the following medical societies: Royal College of Physicians
Disclosure: Nothing to disclose.

Medical Editor

Marjan Garmyn, MD, PhD, Professor, Faculty of Medicine, Katholieke Universiteit Leuven, Belgium; Chair and Adjunct Head, Department of Dermatology, University of Leuven, Belgium
Disclosure: Nothing to disclose.

Pharmacy Editor

Richard P Vinson, MD, Assistant Clinical Professor, Department of Dermatology, Texas Tech University School of Medicine; Consulting Staff, Mountain View Dermatology, PA
Richard P Vinson, MD is a member of the following medical societies: American Academy of Dermatology, Association of Military Dermatologists, Texas Dermatological Society, and Texas Medical Association
Disclosure: Nothing to disclose.

Managing Editor

Jeffrey P Callen, MD, Professor of Medicine, Chief, Division of Dermatology, University of Louisville School of Medicine
Jeffrey P Callen, MD is a member of the following medical societies: Alpha Omega Alpha, American Academy of Dermatology, American College of Physicians, and American College of Rheumatology
Disclosure: Amgen Honoraria Consulting; Abbott Honoraria Consulting; Electrical Optical Sciences Honoraria Consulting; Centocor Honoraria Consulting; Medicis Honoraria Consulting; Celgene Honoraria Consulting

CME Editor

Catherine Quirk, MD, Clinical Assistant Professor, Department of Dermatology, Brown University
Catherine Quirk, MD is a member of the following medical societies: Alpha Omega Alpha and American Academy of Dermatology
Disclosure: Nothing to disclose.

Chief Editor

Dirk M Elston, MD, Director, Department of Dermatology, Geisinger Medical Center
Dirk M Elston, MD is a member of the following medical societies: American Academy of Dermatology
Disclosure: Nothing to disclose.

Acknowledgments

The authors and editors of eMedicine gratefully acknowledge the contributions of previous Chief Editor, William D. James, MD, and previous author, Dr. Ravi Ratnavel, to the development and writing of this article.

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