What causes dark spots in the palm of my hand?

Dark spots on the palm of your hand can be concerning, but they are often caused by benign (harmless) conditions. However, because they can rarely signal a more serious issue, it's important to understand the potential causes.

Here is a breakdown of the most common reasons for dark spots on the palms, from the most frequent to the less common but more serious.

Common and Benign Causes

Sun Exposure (Solar Lentigines or Age Spots):

What it is: These are flat, tan, brown, or black spots caused by years of sun exposure. While they are more common on the backs of the hands, they can also appear on the palms.

How to identify: They are usually uniform in color, have well-defined borders, and don't cause any pain or itching.

Post-Inflammatory Hyperpigmentation (PIH):

What it is: This is a very common cause. After your skin experiences inflammation or an injury (even a minor one you might not notice), it can produce excess melanin (the pigment that gives skin its color) as it heals, leaving a flat, dark spot behind.

Common triggers: Bug bites, burns, friction, allergic reactions (e.g., to soap, jewelry, or plants like poison ivy), eczema, or psoriasis on the palms.

Friction or Repeated Trauma:

What it is: Similar to PIH, constant rubbing or pressure on a specific part of your palm can stimulate melanin production. This is sometimes seen in people who use certain tools, play musical instruments, or have manual jobs.

Warts (Plantar Warts):

What it is: While usually on the soles of the feet, warts can appear on the palms. They are caused by the human papillomavirus (HPV). They sometimes have small, clotted blood vessels that look like tiny black dots (often called "wart seeds").

How to identify: They may feel rough, raised, and can be tender when pressed.

Moles (Nevi):

What it is: Moles can occur anywhere on the skin, including the palms. They are typically harmless collections of pigment cells.

How to identify: They are usually round or oval, uniformly brown or black, and can be flat or raised.

Less Common but Important Medical Causes

Nutritional Deficiencies:

What it is: A severe deficiency in Vitamin B12 or Folate can sometimes lead to hyperpigmentation, including on the palms and soles. This is more common in certain medical conditions or dietary restrictions.

Medical Conditions:

Addison's Disease: This is a rare disorder of the adrenal glands. One classic symptom is hyperpigmentation, which can appear in sun-exposed areas, but also in pressure points, skin folds, and even on the palms. It's often accompanied by other symptoms like severe fatigue, muscle weakness, and weight loss.

Hemochromatosis: This is an iron overload disorder. A bronze or slate-gray skin discoloration, sometimes including the palms, can be a symptom.

Chemical Causes:

What it is: Exposure to certain chemicals, like arsenic, can cause dark spots on the palms and soles. This is very rare today but is a historically known cause.

The Most Serious Cause to Be Aware Of

Acral Lentiginous Melanoma (ALM):

What it is: This is a rare but serious type of skin cancer that can appear on the palms, soles of the feet, or under the nails (subungual). It is the most common type of melanoma in people with darker skin tones but can occur in anyone.

Why it's important: Because it occurs in a less sun-exposed area, it often goes unnoticed until a later stage.

How to identify: Use the ABCDEFG rule for acral melanoma:

A: Asymmetry (one half doesn't match the other)

B: Border (irregular, ragged, or blurred edges)

C: Color (varied shades of brown, black, red, blue, or white)

D: Diameter (larger than 6mm, about the size of a pencil eraser, but can be smaller when first appearing)

E: Evolving (the spot is changing in size, shape, or color)

F: Firm and Flat (it may feel firm to the touch and appear flat initially, though it can become raised)

G: Grows quickly

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What Should You Do?

Don't Panic. The vast majority of dark spots on the palms are benign.

Monitor the Spot. Take a clear photo of it now and compare it again in a month to see if it has changed in size, shape, or color.

See a Dermatologist. This is the most important step. If you notice any of the ABCDEFG warning signs, if the spot is new, or if it's changing, make an appointment to see a doctor or dermatologist. They can examine the spot, often with a dermoscope (a special magnifying tool), and determine if a biopsy is needed to rule out anything serious.

A professional evaluation will give you peace of mind and ensure you get the right treatment if needed.

Disclaimer: This information is for educational purposes only and is not a substitute for professional medical advice. Always consult a healthcare provider for any health concerns or questions about a medical condition.