Read below about darkened skin under the armpit, including causes and common questions. Or get a personalized analysis of your darkened skin under the armpit from our A.I. health assistant. At Buoy, we build tools that help you know what’s wrong right now and how to get the right care.

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10 Potential Darkened Skin Under the Armpit Causes

Disclaimer: The article does not replace an evaluation by a physician. Information on this page is provided as an information resource only, and is not to be used or relied on for any diagnostic or treatment purposes.

  1. 1.Benign Skin Growth

    Seborrheic keratosis is a condition that causes wart-like growths on the skin. The growths are benign (not-cancerous) and look like stuck-on plaques.

    Resolves with treatment

    Rarity:
    Common
    Top Symptoms:
    constant skin changes, itchy rash, rash with well-defined border, abdominal skin changes, neck skin changes
    Symptoms that always occur with benign skin growth:
    constant skin changes
    Symptoms that never occur with benign skin growth:
    cherry red lower leg bump
    Urgency:
    Wait and watch
  2. 2.Skin Abscess

    A skin abscess is an infection of the deeper skin that's typically due to bacteria seen on the skin. Recently, infections are more frequently caused by Staph. Aureus (puts the "staph" in "staph infections").

    Good prognosis with treatment

    Rarity:
    Common
    Top Symptoms:
    pink or red arm bump, painful arm bump, large upper arm bump, marble-sized upper arm bump
    Symptoms that always occur with skin abscess:
    pink or red arm bump
    Symptoms that never occur with skin abscess:
    fever
    Urgency:
    Primary care doctor
  3. 3.Folate (Vitamin) Deficiency

    Folic acid (folate) is a vitamin that is needed to make new cells in the body, including red blood cells which carry oxygen through the blood and into various tissues throughout the body. Folate deficiency refers to a condition when there is not enough folic acid in the body, and can lead to symptoms such as tiredness, low energy, faintness, and difficulty breathing.

    People recover with no long-term effects within weeks.

    Rarity:
    Rare
    Top Symptoms:
    fatigue, depressed mood, irritability, nausea or vomiting, diarrhea
    Symptoms that never occur with folate (vitamin) deficiency:
    abdominal swelling
    Urgency:
    Phone call or in-person visit
  4. 4.Acanthosis Nigricans

    Acanthosis nigricans is a skin condition in which areas of dark, velvety discoloration appear in body folds and creases, such as armpits, the groin area, and the neck area. The skin changes of acanthosis nigricans usually occur in people who have diabetes or are obese.

    Varies

    Rarity:
    Uncommon
    Top Symptoms:
    skin that is darker than it used to be, darkened skin over the neck, constant skin changes
    Symptoms that always occur with acanthosis nigricans:
    skin that is darker than it used to be
    Urgency:
    Primary care doctor
  5. 5.Non - Specific Skin Rash

    A rash is an area of irritated or swollen skin. Often, rashes are unidentifiable and some variation of normal. For example, scratching one's arm causes it to turn red (which is caused by mast cells releasing chemicals into the local area), but that's completely normal.

    1-2 days

    Rarity:
    Common
    Top Symptoms:
    rash
    Symptoms that always occur with non-specific skin rash:
    rash
    Urgency:
    Wait and watch

    Darkened Skin Under the Armpit Checker

    Take a quiz to find out why you’re having darkened skin under the armpit.

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  6. 6.Severe Skin Abscess

    A skin abscess is an infection of the deeper skin that's typically due to bacteria seen on the skin. Recently, infections are more frequently caused by Staph. Aureus (puts the "staph" in "staph infections"). If the infection begins to spread, urgent treatment is required.

    92-96% resolve with treatment within 7-10 days

    Rarity:
    Rare
    Top Symptoms:
    fatigue, fever, pink or red arm bump, worsening upper arm redness, painful arm bump
    Symptoms that always occur with severe skin abscess:
    pink or red arm bump
    Urgency:
    Hospital emergency room
  7. 7.Hemochromatosis

    Hemochromatosis is a disease in which too much iron builds up in the body. This can be hereditary or caused by another condition like liver failure.

    Lifelong

    Rarity:
    Uncommon
    Top Symptoms:
    fatigue, abdominal pain (stomach ache), joint pain, decreased sex drive, frequent urination
    Urgency:
    Primary care doctor
  8. 8.Non - Specific Dermatitis (Skin Inflammation)

    Dermatitis is the inflammation ("-itis") of the skin ("derma" is a layer of the skin). It can be caused by any number of causes, from allergies to infections to autoimmune issues. Dermatitis of Normal Variation (also called, "NOS") means that all of those other causes of your rash have been ruled out. This is very common.

    1-2 days

    Rarity:
    Common
    Top Symptoms:
    red rash, itchy rash, painful rash
    Symptoms that always occur with non-specific dermatitis (skin inflammation):
    red rash
    Urgency:
    Self-treatment
  9. 9.Pimple

    Acne, also known as pimples, occurs when hair follicles become clogged with oil & dead skin cells. Acne is extremely common and ranges from mild to severe.

    The severity of the acne dictates treatment-type and duration. With proper treatment, acne should resolve in weeks to months. In some cases, acne is a long-term condition.

    Rarity:
    Common
    Top Symptoms:
    pink or red arm bump, small upper arm bump, painful arm bump, marble-sized upper arm bump
    Symptoms that always occur with pimple:
    pink or red arm bump
    Urgency:
    Self-treatment
  10. 10.Pancreatic Cancer

    Pancreatic neoplasm affects the pancreas, an organ in the abdomen, and causes symptoms like abdominal pain, back pain, urine changes, fatigue, and weight loss.

    The treatment & prognosis for pancreatic neoplasm vary and are dependent on the disease severity.

    Rarity:
    Rare
    Top Symptoms:
    fatigue, nausea, loss of appetite, diarrhea, unintentional weight loss
    Urgency:
    Primary care doctor

Questions Your Doctor May Ask About Darkened Skin Under the Armpit

  • Q.What is your body mass?
  • Q.Have you ever been diagnosed with diabetes?
  • Q.Have you been feeling more tired than usual, lethargic or fatigued despite sleeping a normal amount?
  • Q.Have someone press on the upper right corner of your abdomen (see picture). Does this person feel a large lump coming from under your rib cage?

If you've answered yes to one or more of these questions, try our darkened skin under the armpit symptom checker to find out more.

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Darkened Skin Under the Armpit Symptom Checker Statistics

  • People who have experienced darkened skin under the armpit have also experienced:

    • 16% Armpit Itch
    • 7% Skin Changes on Armpit
    • 4% Darkened Skin Over the Neck
  • People who have experienced darkened skin under the armpit were most often matched with:

    • 43% Folate (Vitamin) Deficiency
    • 3% Benign Skin Growth
  • Source: Aggregated and anonymized results from visits to the Buoy AI health assistant (check it out by clicking on “Take Quiz”).

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Take a quiz to find out why you’re having darkened skin under the armpit

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