Red Spot Under Toenail 2026: Is It Serious? Podiatrist Explains

A red spot, streak, or discoloration under a toenail is one of those findings that can range from entirely inconsequential (a small capillary rupture from shoe pressure) to clinically serious (subungual melanoma). Getting this distinction right matters — and the clinical exam provides most of the information needed.

Causes of a Red Spot Under the Toenail

1. Splinter Hemorrhage

Splinter hemorrhages are linear, thin, dark red-brown streaks running longitudinally under the nail plate, caused by rupture of capillaries in the nail bed. They look exactly like a tiny splinter embedded under the nail — hence the name.

On toenails, the most common cause is local trauma — repetitive shoe friction, tight footwear, or direct impact. The streaks appear in the distal two-thirds of the nail. The definitive feature: they grow out distally with the nail over 4–8 weeks.

Splinter hemorrhages in the proximal nail (near the cuticle) are more concerning and can be associated with systemic conditions: infective endocarditis, vasculitis, systemic lupus, antiphospholipid syndrome, and psoriasis. If you notice red streaks near the nail base without clear local trauma, a medical evaluation is appropriate.

2. Subungual Hematoma

A subungual hematoma is a collection of blood between the nail plate and nail bed — larger than a splinter hemorrhage. It appears as a dark red to purple-black area under the nail, typically following a clear traumatic event. The classic scenario is dropping something on the toe, stubbing it, or repetitive pressure from running in tight shoes.

Acutely, a subungual hematoma is intensely painful due to pressure build-up under the nail. Trephination (creating a small hole in the nail plate to release the blood) provides immediate pain relief when performed within the first 48 hours. After that, the blood congeals and trephination is less effective.

The critical clinical point: even after a clear trauma, a dark spot or streak under the nail that extends to involve the periungual skin (around the nail fold) should be evaluated to rule out melanoma — the Hutchinson’s sign. Trauma can coexist with an underlying melanocytic lesion that was previously unnoticed.

3. Subungual Melanoma — Must Be Ruled Out

Subungual melanoma is a melanoma arising from the nail matrix or nail bed. It is rare but disproportionately deadly because of delayed diagnosis — the average time from first noticing a nail abnormality to diagnosis is over two years, primarily because patients and clinicians attribute dark nail changes to trauma.

It typically presents as longitudinal melanonychia — a dark brown or black streak running the length of the nail from the matrix proximally to the distal edge. Initially it may look similar to a splinter hemorrhage. The features that distinguish melanoma from benign causes:

• The streak does NOT grow out with the nail — it stays in place or widens over months
• The streak width is greater than 3 mm, or is widening over time
• The pigment color is irregular — variable shades of brown, black, gray within the streak
• Hutchinson’s sign: pigmentation extending from under the nail onto the cuticle or adjacent skin — this is essentially pathognomonic for subungual melanoma and is a dermatologic emergency
• The nail plate is dystrophic, lifted, or destroyed overlying the streak

Subungual melanoma is more common in darker-skinned individuals (it is the most common form of melanoma in African American and Asian populations) but occurs across all skin types. The hallux is the most commonly affected toenail.

4. Glomus Tumor

A glomus tumor is a rare benign neoplasm of the glomus body (a temperature-regulating arteriovenous structure) that occurs most commonly under the nails. It presents as a small red or bluish-red spot under the nail, classically associated with three features: intense paroxysmal pain, cold hypersensitivity (pain triggered by cold exposure), and point tenderness (exquisite pain when the tip of a probe is pressed on the exact spot).

This triad is pathognomonic and should prompt immediate podiatric or dermatologic evaluation. MRI confirms the diagnosis. Treatment is surgical excision, which is curative in nearly all cases.

The Simple Clinical Test: Does It Grow Out?

For any red or dark spot under the toenail where the cause is uncertain, the single most useful observation is whether the spot moves distally with nail growth over 4–6 weeks. Mark the proximal edge of the spot with a fine-tip marker on the nail, photograph it, and recheck in 4 weeks.

If the mark has moved forward by 1–2 mm (consistent with nail growth rate), the spot is within the nail plate from a prior capillary injury — benign. If the proximal edge of the pigmentation has not moved, the source is in the nail matrix — and melanoma must be excluded with biopsy.

Frequently Asked Questions

Can a red spot under the toenail be dangerous?
Usually not — trauma-related splinter hemorrhages and subungual hematomas are the most common causes and both are benign. However, a dark or red spot that does not grow out with the nail, is widening, or extends to the skin around the nail must be evaluated promptly to rule out subungual melanoma.

Should I be worried about a dark line under my toenail?
A dark longitudinal line (streak) running the length of the nail is melanonychia. If it appeared after a clear trauma and is growing out, it is likely a blood streak. If it appeared without trauma, is widening, or has Hutchinson’s sign, it requires biopsy. Do not wait — subungual melanoma detected early is highly curable; detected late, it carries a poor prognosis.

The Bottom Line

A red spot under a toenail is usually benign — the vast majority are splinter hemorrhages or hematomas from shoe pressure or direct trauma. The critical clinical rule: watch whether it grows out. A spot that grows forward with the nail is benign. A streak that stays in place, widens, or extends to the periungual skin is a melanoma until proven otherwise — see a podiatrist or dermatologist immediately.

Sources

1. Ruben BS. “Pigmented lesions of the nail unit.” Semin Cutan Med Surg. 2010.
2. Phan A, et al. “Acral lentiginous melanoma: a clinicoprognostic study.” Br J Dermatol. 2007.
3. Scheinfeld N. “Glomus tumors: a brief review and update.” Dermatol Online J. 2014.

Related guides on nail spots

More on marks and spots under the nail:

• Black spot under the toenail
• Bruised toenail
• Nail & skin conditions hub