Health professionals are urging people to pay closer attention to their feet after highlighting a potentially serious warning sign that often goes unnoticed: dark streaks appearing on toenails.

Pharmacists have issued guidance reminding the public that vertical dark stripes on toenails, along with other nail changes, can sometimes indicate underlying health problems ranging from nutrient deficiencies to melanoma—a potentially deadly form of skin cancer.

The Warning Sign Many People Miss

The concern centers on a condition called longitudinal melanonychia, which appears as dark brown or black vertical bands running from the base to the tip of the nail. While these streaks can have benign causes, they may occasionally signal subungual melanoma, a rare but serious form of skin cancer that develops beneath the nail.

"People often forget to check their feet during routine health examinations," according to pharmacy professionals quoted in recent health guidance. "Yet changes in toenails can provide important clues about overall health status."

The warning comes as part of broader public health efforts to improve early detection of melanoma, which has significantly better outcomes when caught in its earliest stages. According to Cancer Research UK, melanoma survival rates exceed 90% when diagnosed early, but drop substantially if the cancer has spread.

Understanding the Risk

Subungual melanoma accounts for only 0.7% to 3.5% of all melanoma cases in white populations, but represents a higher proportion—up to 35%—in people with darker skin tones, according to medical literature. This disparity makes awareness particularly important across all demographic groups.

The condition gained public attention following high-profile cases, including reggae legend Bob Marley, who died from melanoma that originated under his toenail. Marley initially dismissed the dark spot as a soccer injury, delaying diagnosis until the cancer had spread.

However, experts stress that dark streaks on nails are far more commonly caused by benign conditions. These include trauma to the nail, fungal infections, vitamin B12 deficiency, or simply increased melanin production—a normal occurrence, particularly in people with darker skin.

When to Seek Medical Attention

Health professionals recommend consulting a doctor if you notice:

A new dark streak appearing on a toenail, especially if it's widening or changing color over time. Streaks that extend onto the surrounding skin (known as Hutchinson's sign). Nail changes accompanied by bleeding, pain, or separation of the nail from the nail bed. A dark streak appearing on only one nail, particularly in fair-skinned individuals over age 50.

"The key is knowing what's normal for you," dermatologists emphasize. "Any new or changing mark deserves professional evaluation."

Beyond Cancer: Other Nail Warning Signs

Pharmacists note that toenail changes can indicate various health conditions beyond melanoma. Yellowing nails may suggest fungal infection or, less commonly, lung disease or diabetes. Thick, crumbly nails often indicate fungal infection, particularly common in older adults. White spots typically result from minor trauma rather than calcium deficiency, contrary to popular belief. Spoon-shaped nails (koilonychia) can indicate iron deficiency anemia.

Clubbing of the nails—where the nail curves downward and the fingertip appears bulbous—may signal heart or lung conditions and warrants medical evaluation.

The Importance of Foot Self-Examinations

Public health guidance recommends incorporating feet into regular body checks, particularly for individuals at higher risk of melanoma. Risk factors include fair skin that burns easily, a history of excessive sun exposure or sunburn, family history of melanoma, and having numerous moles or atypical moles.

"We examine our faces daily but rarely give our feet the same attention," health professionals note. "A monthly check of your feet, including the soles and between toes, takes just minutes but could prove lifesaving."

For those with limited mobility or vision difficulties, asking a family member or healthcare provider for assistance with foot examinations is recommended.

The Bottom Line on Toenail Changes

While the vast majority of toenail discoloration proves harmless, the message from health professionals is clear: when in doubt, get it checked out. Early detection remains the most powerful tool in treating melanoma and other serious conditions.

General practitioners can perform initial assessments and refer patients to dermatologists if needed. Dermatoscopy—a non-invasive examination using a specialized magnifying device—can often distinguish benign changes from those requiring biopsy.

The guidance serves as a reminder that cancer screening isn't limited to formal programs. Simple self-awareness and willingness to seek medical advice about unusual changes remain fundamental to early detection.

As healthcare systems emphasize prevention and early intervention, paying attention to often-overlooked areas like toenails represents a simple but potentially crucial health habit—one that requires no special equipment, just mindful attention during routine personal care.