What Could be Causing Dark Lines Under Fingernails?

What Causes Dark Lines Under Fingernails?

Dark lines under fingernails can have various causes, just like most other symptoms. Finding the true cause means ruling out or confirming each possibility – in other words, diagnosis.

Diagnose your symptoms now!

check your overall health status
identify any nutritional deficiencies
learn what you should be doing right now

Diagnosis is usually a complex process due to the sheer number of possible causes and related symptoms. In order to diagnose dark lines under fingernails, we could:

Research the topic
Find a doctor with the time
Use a diagnostic computer system.

The process is the same, whichever method is used.

Step 1: List all Possible Causes

We begin by identifying the disease conditions which have "dark lines under fingernails" as a symptom. For example, melanoma.

Step 2: Build a Symptom Checklist

We then identify all possible symptoms and risk factors of each possible cause, and check the ones that apply:

bleeding/enlarging/tender moles

melanoma in family members

mouth sores

light hair

black/brown fingernails

having many common moles

lighter/paler skin color

very many irregular dark moles

history of melanoma

light eye color

melanoma

... and so on

Step 3: Rule Out or Confirm each Possible Cause

A differential diagnosis of your symptoms and risk factors finds the likely cause of dark lines under fingernails.

Arriving at a Correct Diagnosis

The Analyst™ is our online diagnosis tool that learns all about you through a straightforward process of multi-level questioning, providing diagnosis at the end.

If you indicate abnormal fingernails and toenails, The Analyst™ will ask further questions including this one:

Do you have any dark lines/streaks below the nails, running in the direction of nail growth?

Possible responses:

→ No / don't know
→ Yes

Based on your response to this question, which may indicate dark lines under nails, The Analyst™ will consider possibilities such as Melanoma. Dark lines beneath the nail should be investigated as soon as possible.

Concerned or curious about your health? Try The Analyst™