A patient, aged 72 years, presented with concerns about discoloration of a toe nail, which he first noted four weeks ago. The patient denied antecedent trauma or a similar condition in past.
Examination revealed reddish black pigmentation of a lateral nail fold. There was no diffusion of pigment or significant joint changes. Dermoscopic examination revealed well circumscribed annular dots dispersed in a homogeneous pattern.
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A subungual hemorrhage, or a subungual hematoma, is a common cause of hyperpigmented nails. It results from blood accumulation within the area between the nail matrix and the nail bed due to an injury or a repetitive trauma.1
The condition characteristically presents as brown-black nail pigmentation that moves distally as the nail plate grows.2,3 In 15% of subungual hemorrhages, the hemorrhages do not migrate, which makes diagnosis difficult.4 Dermoscopy, a non-invasive tool, may be used to improve accuracy in diagnosis based on color and pattern of pigmentation.
Dermoscopy of the affected nail shows homogenous and globular patterns, in addition to streaks, peripheral fading and periungual hemorrhages that depend on the time and volume of bleeding. 1,5 While they appear brown or black with the naked eye, they also may exhibit red and purple pigmentation under dermoscopy. The variation in colors is due to breakdown of hemoglobin from the blood into hemosiderin by phagocytes.1 If diagnosis is still questionable by history, clinical appearance, or dermoscopy, a biopsy should be performed.
Subungual hemorrhages with large accumulations of blood are treated to prevent separation and loss of the nail plate. A most effective method of treatment for hematomas of recent onset is by puncture of the nail with a hot paperclip or large-bore needle to drain the blood.
The hematoma can also be decompressed with a carbon dioxide laser that melts the center of the discolored portion in the nail. A more painful procedure that requires a nerve block is trephining of the nail with a drill.6 If the hemorrhage is small and asymptomatic, treatment is not necessary because the pigmentation will gradually grow out.
Nail pigmentation may pose a diagnostic challenge — differential diagnoses include benign nevus, malignant melanoma, pseudomonas infection, glomus tumor or drug induced pigmentation. Of these conditions, a pseudomonas infection will cause a green nail hue.2 Malignant melanoma may present as a hyperpigmented band with diffusion of pigment into the nail folds, known as the Hutchinson sign.1, 2
When trauma is noted in the history, subungual hemorrhage is the most common cause of discoloration. However, diagnosis can be difficult in patients who have no clear evidence of trauma and the option of observation versus biopsy must be weighed by the clinician.
Megha D. Patel is a student at The Commonwealth Medical College in Scranton, Pennsylvania.
Stephen Schleicher, MD, is an associate professor of Medicine at the Commonwealth Medical College and an Adjunct Assistant Professor of Dermatology at the University of Pennsylvania Medical College. He practices dermatology in Hazleton, Pennsylvania.
- Mun JD, Kim GW, Jwa SW, et al. British Journal of Dermatology. 2013; doi: 10.1111/bjd.12209
- Haenssle HA, Blum A, Hofmann-Wellenhof R, et al. Dermatol Pract Concept. 2014; 10.5826/dpc.0404a02
- Braun RP, Baran R, Le Gal FA et al. J Am Acad Dermatol. 2007; 56:835-47
- Zaias N. (1990.) The Nail in Health and Disease. (2nd ed.) Norwalk, Connecticut: Appleton & Lange.
- Sato T, Tanaka M. Dermatol Prac and Concept. 2013; 10.5826/dpc.0402a18
- Habif TP.(2010.) Subungual hematoma. In Clinical Dermatology. (5th ed.), 821-964. Philadelphia: Elsevier.