Pallor (Paleness): Meaning and Causes

What pallor means

Skin color comes from melanin (pigment) and from blood flowing in small vessels near the surface. Red blood cells carry hemoglobin, which gives oxygenated blood its red color. Pallor describes a reduction in that red tone. It is different from naturally fair skin, which is a person's normal coloring.

Doctors distinguish:

• Generalized pallor: the whole body, usually from anemia or reduced blood flow.
• Localized pallor: one limb or finger, from a blocked artery or a spasm of blood vessels.

Checking for pallor on different skin tones

Pallor can be hard to see on darker skin. Look at areas with less pigment:

• the inside of the lower eyelids (conjunctiva), which should be pink-red
• the lips, gums and tongue
• the palms and the creases of the hands
• the nail beds

Darker skin may look grayish or ashen rather than pale.

Causes of pallor

Gradual pallor

• Anemia: the most common cause. Types include iron deficiency anemia from heavy periods, pregnancy, poor diet or slow bleeding from the gut; vitamin B12 or folate deficiency; anemia of chronic disease; and kidney disease.
• Chronic illness: kidney failure, heart failure, cancer and inflammatory conditions.
• Underactive thyroid: pale, dry, cool skin with tiredness and weight gain.
• Lack of sunlight: looking "pale" from being indoors, without any illness.
• Blood cancers: leukemia causes pallor with fatigue, bruising, bleeding, infections and sometimes bone pain or fever.
• Lead poisoning in children.

Sudden pallor

• Fainting (vasovagal syncope): pallor, sweating, nausea and lightheadedness before passing out, often triggered by pain, standing for long periods or the sight of blood. See vasovagal syncope.
• Hypoglycemia: low blood sugar causes pallor, sweating, shakiness, hunger and confusion, especially in people treated with insulin or certain diabetes tablets.
• Shock: from bleeding, severe infection (sepsis), severe allergic reaction or heart failure. Skin becomes pale, cold and clammy. See shock.
• Sudden blood loss: internal or external bleeding.
• Panic attacks and intense fear.
• Cold exposure.
• Heart rhythm problems reducing blood output.

Localized pallor

• Raynaud's phenomenon: fingers or toes turn white, then blue, then red with cold or stress.
• Arterial blockage: a sudden pale, cold, painful, numb limb is an emergency.
• Frostbite.

Pallor in children

The most common cause in toddlers is iron deficiency, often from drinking large amounts of cow's milk (more than about 24 ounces, 700 ml, a day), which is low in iron and reduces appetite for iron-rich food. Other causes include infections, thalassemia trait and, rarely, leukemia. A pale child with bruising, fever, bone pain or swollen glands needs prompt assessment.

Pallor with other symptoms

How doctors assess pallor

The doctor will ask about diet, periods, blood loss, medicines and other symptoms, then examine the skin, eyes, heart, belly (spleen and liver size) and lymph nodes. Common tests:

• Complete blood count to measure hemoglobin and red cell size
• Ferritin and iron studies, vitamin B12 and folate
• Reticulocyte count, bilirubin and other tests if red cell breakdown is suspected
• Blood glucose in sudden pallor
• Stool tests or endoscopy if gut bleeding is suspected
• Kidney, liver and thyroid tests

Treatment

Pallor improves when the cause is treated:

• Iron deficiency: iron supplements or IV iron, plus finding and treating the cause of iron loss.
• B12 or folate deficiency: replacement by injection or tablets.
• Low blood sugar: fast-acting sugar such as juice or glucose tablets, then a snack.
• Fainting: lie down and raise the legs until color returns.
• Shock or bleeding: emergency care.
• Raynaud's: keep hands and feet warm and avoid smoking.

Frequently asked questions

What is the medical definition of pallor?

Pallor is an abnormal paleness of the skin and mucous membranes caused by reduced oxyhemoglobin, either from a lower number of red blood cells (anemia) or reduced blood flow to the skin. It is a physical sign that prompts a search for the underlying cause.

What is the most common cause of pallor?

Anemia, especially iron deficiency anemia, is the most common cause of ongoing pallor. Common reasons include heavy periods, pregnancy, low dietary iron and slow bleeding from the gut. A blood count confirms it.

When is pallor an emergency?

Pallor is an emergency when it comes on suddenly with cold, clammy skin, a racing pulse, dizziness, confusion, chest pain, breathing difficulty, heavy bleeding or after an injury. These can be signs of shock. Call 911 or your local emergency number.

Can stress make you look pale?

Yes. Fear, anxiety and panic release adrenaline, which narrows blood vessels in the skin and can make you look pale for a short time. This resolves as you calm down. Persistent pallor is not explained by stress and should be checked with a blood test.