Brown Band on Teenager's Thumb: What Cause?

Consultant for PediatriciansConsultant for Pediatricians Vol 6 No 6
Volume 6
Issue 6

A brown band runs along the longitudinal axis of this teenager’s thumb.

THE CASE: A brown band runs along the longitudinal axis of this teenager’s thumb.

(Answer and discussion on next page.) 


Melanonychia striata is the correct answer.

DISCUSSION:Melanonychia striata is characterized by a brown or black band that runs along the longitudinal axis of the nail. The condition is common in blacks, Chinese, and other relatively dark-skinned persons, but it is rare in whites. The thumbs and index fingers are most commonly affected.

Melanonychia striata results from activity of melanocytes in the nail matrix. It may occur spontaneously or as a result of trauma, irradiation, gold therapy, or treatment with cytotoxic agents. It may also be a sign of arsenic intoxication, hemochromatosis, Addison disease, or vitamin B12 deficiency.

Subungual melanoma is included in the differential diagnosis of melanonychia striata. Findings that suggest melanoma include an abrupt onset after middle age, a band width greater than 6 mm, rapid growth, variegated coloring, blurry edges, and nail dystrophy. Hutchinson-the spread of pigmentation into the proximal and lateral nail files-is highly suggestive of subungual melanoma.

Polling Software


Survey Software

Case and image courtesy of Alexander K. C. Leung, MD and C. Pion Kao, MD, Alberta Children’s Hospital, Calgary.




Related Videos
Angela Nash, PhD, APRN, CPNP-PC, PMHS | Image credit: UTHealth Houston
Allison Scott, DNP, CPNP-PC, IBCLC
Joanne M. Howard, MSN, MA, RN, CPNP-PC, PMHS & Anne Craig, MSN, RN, CPNP-PC
Juanita Mora, MD
Natasha Hoyte, MPH, CPNP-PC
Lauren Flagg
Venous thromboembolism, Heparin-induced thrombocytopenia, and direct oral anticoagulants | Image credit: Contemporary Pediatrics
Sally Humphrey, DNP, APRN, CPNP-PC | Image Credit: Contemporary Pediatrics
© 2024 MJH Life Sciences

All rights reserved.