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Neonatal Pustular Melanosis Workup

  • Author: Robert A Silverman, MD; Chief Editor: Dirk M Elston, MD  more...
Updated: Nov 04, 2014

Laboratory Studies

If the appearance is typical of transient neonatal pustular melanosis, no further workup is indicated. If appearance is not typical, potassium hydroxide preparation, Gram stain, and Wright-Giemsa stain can support other diagnoses in the differential. In atypical cases, pustules can be cultured for bacteria and clustering of pustules should prompt polymerase chain reaction to identify possible herpes simplex.

Wright-Giemsa stain of pustule contents demonstrates a predominance of neutrophils. Few, if any eosinophils are present. The brown macules are not true freckles or lentigines. Skin biopsy shows pigment incontinence characteristic of postinflammatory hyperpigmentation. The diagnosis of Langherhans cell histiocytosis can only be made by skin biopsy.

Contributor Information and Disclosures

Robert A Silverman, MD Clinical Associate Professor, Department of Pediatrics, Georgetown University Medical Center

Robert A Silverman, MD is a member of the following medical societies: American Academy of Dermatology, Society for Pediatric Dermatology

Disclosure: Nothing to disclose.

Specialty Editor Board

Mary L Windle, PharmD Adjunct Associate Professor, University of Nebraska Medical Center College of Pharmacy; Editor-in-Chief, Medscape Drug Reference

Disclosure: Nothing to disclose.

Robert A Schwartz, MD, MPH Professor and Head of Dermatology, Professor of Pathology, Pediatrics, Medicine, and Preventive Medicine and Community Health, Rutgers New Jersey Medical School; Visiting Professor, Rutgers University School of Public Affairs and Administration

Robert A Schwartz, MD, MPH is a member of the following medical societies: Alpha Omega Alpha, New York Academy of Medicine, American Academy of Dermatology, American College of Physicians, Sigma Xi

Disclosure: Nothing to disclose.

Chief Editor

Dirk M Elston, MD Professor and Chairman, Department of Dermatology and Dermatologic Surgery, Medical University of South Carolina College of Medicine

Dirk M Elston, MD is a member of the following medical societies: American Academy of Dermatology

Disclosure: Nothing to disclose.

Additional Contributors

Kevin P Connelly, DO Clinical Assistant Professor, Department of Pediatrics, Division of General Pediatrics and Emergency Care, Virginia Commonwealth University School of Medicine; Medical Director, Paws for Health Pet Visitation Program of the Richmond SPCA; Pediatric Emergency Physician, Emergency Consultants Inc, Chippenham Medical Center

Kevin P Connelly, DO is a member of the following medical societies: American Academy of Pediatrics, American College of Osteopathic Pediatricians, American Osteopathic Association

Disclosure: Nothing to disclose.


The authors and editors at Medscape Reference gratefully acknowledge the contributions of previous author Elaine B St John, MD, to the original writing and development of this article.

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Ruptured pustules and vesicles with remaining characteristic collarette of scale and brown hyperpigmented macules. Courtesy of Anthony J. Mancini, MD.
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