Why do skin and nail go blue in cyanosis?

Why do skin and nail go blue in cyanosis?

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I have learned that Cyanosis presents with blue skin and nails. What is the reason for the blue coloration of the skin and nails? Why wont the skin and nails turn another color in the visible spectrum such as green for instance? How is this disease diagnosed?

The skin appears blue due to the diffraction of light through the skin. Blood is either bright red (sufficiently oxygenated) or dark red. "The blue appearance of surface veins is caused mostly by the scattering of blue light away from the outside of venous tissue if the vein is at 0.5 mm deep or more. Veins and arteries appear similar when skin is removed and are seen directly" 1. The color of blood is due to the difference in color between deoxyhemoglobin and oxyhemoglobin.

Let's consider the "blue fugates" of Kentucky. The ancestors of this family have different shades of blue skin tones. Dr. Madison Cawein discovered that the family had a high concentration of FE$^{3+}$ brown methemoglobin. This form is useless to the body so the enzyme diaphorase reduces the methemoglobin to FE$^{2+}$ (hemoglobin that can carry oxygen) [2].

Basically the skin color comes down to light diffraction not the blood changing from red to blue.

Cyanosis is the appearance of a blue or purple coloration of the skin or mucous membranes due to the tissues near the skin surface having low oxygen saturation [3]. Cyanosis is a clinical sign diagnosed visually. Cyanosis is an indication for blood gas testing.



When haemoglobin takes on oxygen the colour will shift from blue to red. the reason for this is a change in orientation of the Nitrogen ligans of the haemoglobin molecule.

The red cells pass through the veins in the lung(s) to the aevioli; the blue haem (pH~7.2) exchanges CO2 for O2 (now pH~7.4) 98% saturation and goes from blue to red.

We see the colour(s) because the haemoglobin's Fe in the centre of the ring goes in and out of plane to the ring. The colour comes for this phenomenon due to the 4 Nitrogen atoms and the electron states that exist without and with oxygen. This takes place within about 12milliseconds.

Hope this helps.

Why do skin and nail go blue in cyanosis? - Biology

The color of skin is influenced by a number of pigments, including melanin, carotene, and hemoglobin. Recall that melanin is produced by cells called melanocytes, which are found scattered throughout the stratum basale of the epidermis. The melanin is transferred into the keratinocytes via a cellular vesicle called a melanosome (Figure 1).

Figure 1. The relative coloration of the skin depends of the amount of melanin produced by melanocytes in the stratum basale and taken up by keratinocytes.

Melanin occurs in two primary forms. Eumelanin, the most common form of melanin, exists as black and brown, whereas pheomelanin provides a red color. Dark-skinned individuals produce more melanin than those with pale skin. Exposure to the UV rays of the sun or a tanning salon causes melanin to be manufactured and built up in keratinocytes, as sun exposure stimulates keratinocytes to secrete chemicals that stimulate melanocytes. The accumulation of melanin in keratinocytes results in the darkening of the skin, or a tan. This increased melanin accumulation protects the DNA of epidermal cells from UV ray damage and the breakdown of folic acid, a nutrient necessary for our health and well-being. In contrast, too much melanin can interfere with the production of vitamin D, an important nutrient involved in calcium absorption. Thus, the amount of melanin present in our skin is dependent on a balance between available sunlight and folic acid destruction, and protection from UV radiation and vitamin D production.

It requires about 10 days after initial sun exposure for melanin synthesis to peak, which is why pale-skinned individuals tend to suffer sunburns of the epidermis initially. Dark-skinned individuals can also get sunburns, but are more protected than are pale-skinned individuals. Melanosomes are temporary structures that are eventually destroyed by fusion with lysosomes this fact, along with melanin-filled keratinocytes in the stratum corneum sloughing off, makes tanning impermanent.

Too much sun exposure can eventually lead to wrinkling due to the destruction of the cellular structure of the skin, and in severe cases, can cause sufficient DNA damage to result in skin cancer. When there is an irregular accumulation of melanocytes in the skin, freckles appear. Moles are larger masses of melanocytes, and although most are benign, they should be monitored for changes that might indicate the presence of cancer (Figure 2).

Figure 2. Moles range from benign accumulations of melanocytes to melanomas. These structures populate the landscape of our skin. (credit: the National Cancer Institute)

Practice Question

What determines the color of skin, and what is the process that darkens skin when it is exposed to UV light?

Integumentary System

The first thing a clinician sees is the skin, and so the examination of the skin should be part of any thorough physical examination. Most skin disorders are relatively benign, but a few, including melanomas, can be fatal if untreated. A couple of the more noticeable disorders, albinism and vitiligo, affect the appearance of the skin and its accessory organs. Although neither is fatal, it would be hard to claim that they are benign, at least to the individuals so afflicted.

Figure 3. Individuals with vitiligo experience depigmentation that results in lighter colored patches of skin. The condition is especially noticeable on darker skin. (credit: Klaus D. Peter)

Albinism is a genetic disorder that affects (completely or partially) the coloring of skin, hair, and eyes. The defect is primarily due to the inability of melanocytes to produce melanin. Individuals with albinism tend to appear white or very pale due to the lack of melanin in their skin and hair. Recall that melanin helps protect the skin from the harmful effects of UV radiation. Individuals with albinism tend to need more protection from UV radiation, as they are more prone to sunburns and skin cancer. They also tend to be more sensitive to light and have vision problems due to the lack of pigmentation on the retinal wall. Treatment of this disorder usually involves addressing the symptoms, such as limiting UV light exposure to the skin and eyes. In vitiligo, the melanocytes in certain areas lose their ability to produce melanin, possibly due to an autoimmune reaction. This leads to a loss of color in patches (Figure 3). Neither albinism nor vitiligo directly affects the lifespan of an individual.

Other changes in the appearance of skin coloration can be indicative of diseases associated with other body systems. Liver disease or liver cancer can cause the accumulation of bile and the yellow pigment bilirubin, leading to the skin appearing yellow or jaundiced (jaune is the French word for “yellow”). Tumors of the pituitary gland can result in the secretion of large amounts of melanocyte-stimulating hormone (MSH), which results in a darkening of the skin. Similarly, Addison’s disease can stimulate the release of excess amounts of adrenocorticotropic hormone (ACTH), which can give the skin a deep bronze color. A sudden drop in oxygenation can affect skin color, causing the skin to initially turn ashen (white). With a prolonged reduction in oxygen levels, dark red deoxyhemoglobin becomes dominant in the blood, making the skin appear blue, a condition referred to as cyanosis (kyanos is the Greek word for “blue”). This happens when the oxygen supply is restricted, as when someone is experiencing difficulty in breathing because of asthma or a heart attack. However, in these cases the effect on skin color has nothing do with the skin’s pigmentation.



Cyanosis is a bluish discoloration of the skin, mucous membranes, tongue, lips, or nail beds and is due to an increased concentration of reduced hemoglobin (Hb) in the circulation. 1 Clinically evident cyanosis typically occurs at an oxygen saturation of 85% or less. 2 Mild cyanosis may be difficult to detect. Cyanosis is usually easier to detect with natural lighting and is typically more difficult to detect in patients with dark skin pigmentation or with anemia. Long-term complications include clubbing, polycythemia, cerebrovascular accident, brain abscess, platelet abnormalities, lower-than-expected IQ, scoliosis, and hyperuricemia. 1

Central cyanosis is associated with arterial desaturation and involves the skin, mucous membranes, lips, tongue, and nail beds. Peripheral cyanosis occurs when there is increased oxygen uptake in peripheral tissues it is not associated with arterial desaturation. Peripheral cyanosis often involves only the extremities. 1 Differential cyanosis, in which the upper extremities are pink and the lower extremities are cyanotic, is associated with conditions such as coarctation of the aorta and interrupted aortic arch when there is right-to-left shunting through a patent ductus arteriosus. 3 In newborns, acrocyanosis, or blueness of exposed extremities, is common and is typically insignificant. Similarly, isolated circumoral cyanosis due to prominent venous plexuses in the skin is insignificant, as long as cardiac output is normal. 1

Why Are My Fingernails Blue? 5 Conditions That Cause Cyanosis

Now, let’s look at some specific illnesses and circumstances that cause your fingernails or toenails to change color to blue.

1. Carbon Monoxide Poisoning

CO poisoning comes with headaches, weakness, dizziness, vomiting, and chest pain. The condition can cause confusion as well. You probably know that it can be fatal – hundreds of people across the US die of unintentional carbon monoxide poisoning every year.

It’s not always easy to spot the symptoms, and cyanosis can be a good indicator that something is wrong. If you suspect, for any reason, that there are dangerous levels of CO in your home or your vehicle, leave immediately and contact emergency services.

2. Raynaud’s Phenomenon

Blue or pale fingernails are one of the top symptoms of Raynaud’s phenomenon. This disease comes with numb and cold fingers and toes. A Raynaud’s attack shouldn’t be excessively painful, but it’s uncomfortable and can disrupt your everyday routine. Once the attack passes, your fingers will start throbbing and stinging as they warm up again.

The causes behind this phenomenon aren’t clear yet, but doctors believe it comes from a spasm in the blood vessels. Cold temperatures can trigger it. People who work with vibrating tools, such as jackhammers, are at an increased risk. Repetitive motions like typing can put you at risk too.

Since the condition can cause serious complications, you should talk to your doctor about it. There are medications, like vasodilators, that can help reduce the frequency and severity of attacks. Chemical injections and surgery can be an option as well.

3. PVD

PVD stands for peripheral vascular disease, a painful blood vessel condition. People with PVD have narrowed blood vessels, which leads to pain and fatigue.

If you leave it untreated, this condition can have very serious consequences. Clots could form in the blood, blocking off your blood vessels entirely. This leads to irreparable organ damage.

Sometimes, PVD can be a direct response to the environment. For example, it can come from emotional stress or from operating vibrating machinery. But for many people, it comes from diseases that affect the blood vessels, such as diabetes and high blood pressure. Smokers are at an increased risk of PVD, and it tends to affect older people more often.

This condition can be treated with lifestyle changes and medication. When PVD leads to the formation of dangerous clots, surgery or angioplasty may be necessary.

4. Pulmonary Embolism

When a blood clot occurs in the lungs, it leads to pulmonary embolism. This is lethal in one of three cases, and it requires immediate medical attention.

In many cases, it causes blue nails and blue skin. You may also feel chest pain, an irregular heartbeat, lightheadedness, or anxiety. Sometimes, it leads to people spitting up blood, but that symptom isn’t always present.

Doctors can use a chest X-ray, an ECG, and many other forms of diagnostics to find the problem. In the case of minor clots, they’ll prescribe clot-dissolving drugs and anticoagulants. But in more serious cases, immediate surgery is necessary.

5. Emphysema

This is a serious and incurable respiratory condition that mainly affects smokers. Emphysema often comes with blue lips and fingernails. Other symptoms include a fast heartbeat, weight loss, depression and intense fatigue.

Coughing is the top symptom of emphysema. Additionally, people who have a mild form of this condition tend to get winded after strenuous physical activity. As it progresses, they feel out of breath even when they’re resting.

If you suspect you have emphysema, contact a doctor right away. There are ways they can slow the progression of the disease. Steroids and other drugs help keep your blood vessels in good condition. You may also need to take antibiotics to prevent infections like pneumonia that make emphysema worse.

Some people need surgery to remove the damaged parts of the lung. But before taking that option, your doctors may prescribe oxygen therapy. In extremely severe cases, emphysema patients need 24/7 oxygen therapy.

Bluish skin can be a sign of many serious medical problems. Call or visit your health care provider.

For adults, call your doctor or 911 if you have bluish skin and any of the following:

  • You cannot get a deep breath or your breathing is getting harder, or faster
  • Need to lean forward when sitting to breathe
  • Are using muscles around the ribs to get enough air
  • Have chest pain
  • Are having headaches more often than usual
  • Feel sleepy or confused
  • Have a fever
  • Are coughing up dark mucus

For children, call the doctor or 911 if your child has bluish skin and any of the following:

  • Hard time breathing
  • Chest muscles moving in with each breath
  • Breathing faster than 50 to 60 breaths per minute (when not crying)
  • Making a grunting noise
  • Sitting with shoulders hunched over
  • Is very tired
  • Is not moving around much
  • Has a limp or floppy body
  • Nostrils are flaring out when breathing
  • Does not feel like eating
  • Is irritable
  • Has trouble sleeping

Peripheral cyanosis: Causes of blue hands and feet

Peripheral cyanosis is when the hands, fingertips, or feet turn blue because they are not getting enough oxygen-rich blood.

Cold temperatures, circulation problems, and tight jewelry are common causes of peripheral cyanosis.

In this article, we take a close look at peripheral cyanosis, including its causes, symptoms, and treatment. We also look at another type of cyanosis called central cyanosis that affects central parts of the body, the lips, or the tongue.

Cyanosis gets its name from the word cyan, which means a blue-green color.

People with peripheral cyanosis may notice the following symptoms:

  • the skin on the fingertips, toes, palms, or feet is bluey-green
  • the affected body part feels cold to the touch
  • the color returns to normal after warming up the body part

All organs and tissues of the body need oxygen to carry out their functions. A person’s body absorbs oxygen from the air that they breathe. The blood contains a protein called hemoglobin that carries oxygen to the body’s cells. If the body cannot deliver enough oxygen to parts of the body, cyanosis may occur.

Certain medical conditions can prevent oxygen-rich blood from reaching parts of the body. Sometimes, people are born with abnormal hemoglobin, which affects the hemoglobin’s ability to bind to oxygen and carry it to the cells.

People tend to experience cyanosis in the extremities of their body, such as their fingertips and feet. This is because these body parts are furthest away from the heart, so the blood has further to travel.

Common causes of peripheral cyanosis include:

  • Raynaud’s syndrome. Raynaud’s disease is a condition where the fingertips and toes become painful and become blue or white in cold temperatures. This happens when the blood vessels narrow, preventing blood from reaching the extremities.
  • Low blood pressure. Low blood pressure is when there is not enough pressure to push blood and oxygen to the hands and feet. Low blood pressure is also called hypotension.
  • Hypothermia. This is where the body temperature drops to dangerously low levels. Hypothermia is a medical emergency.
  • Vein or artery problems. If a person has problems with their veins or arteries, their bodies may not send enough blood and oxygen to their hands and feet. Possible causes include venous insufficiency, peripheral vascular disease, or blockages in the veins or arteries.
  • Heart failure. When a person has heart failure, their heart may not be able to pump blood around the body effectively.
  • Problems with the lymph system. Lymphatic dysfunction is a condition where the lymph fluid does not flow and drain as it should. This often results in tissues that swell up with lymph fluid.
  • Deep vein thrombosis. This is caused by clots that form in the veins in the leg or limb extremities.
  • Hypovolemic shock. When a person experiences hypovolemic shock, their body diverts blood from the skin towards the internal organs.

Peripheral vs. central cyanosis

The key difference between peripheral and central cyanosis is how they affect the body.

Peripheral cyanosis affects a person’s hands or legs, especially the extremities, such as fingertips, fingernails, and feet. It may affect just one side of the body or both sides equally.

Central cyanosis affects the core organs of the body, causing a blue-green tint across central areas of the body, the lips, or the tongue. The symptoms of central cyanosis do not get better when the body part is heated up.

Both central and peripheral cyanosis have similar causes, including problems with the heart, blood, lungs, or nervous system.

What is Cyanosis?

By medical definition, cyanosis is a condition in which your skin takes on a slight blue or purple discoloration due to a lack of oxygenated blood in the skin and mucus membranes. The blue color is from an increased concentration of deoxyhemoglobin. This is generally considered a serious condition that requires immediate medical attention, although there are some forms of cyanosis that are less serious, and typically temporary. When your blood becomes deoxygenated, the change in color may be gradual, beginning in the nail beds and extremities.

However, when there is a more serious problem, other areas in your torso may also take on a blue tinge, along with your lips and tongue. At this point, seek a doctor as soon as possible, as this can be a sign of extreme hypoxia &ndash a lack of oxygen reaching the tissues.

Cyanosis on lips and tongue (Photo Credit : Zay Nyi Nyi/Shutterstock)

What to do if cyanosis develops

Call for an ambulance or go to your nearest hospital emergency department immediately if you notice an adult or child suddenly turning blue, particularly if they have other symptoms, such as difficulty breathing or chest pain . This could be a sign of a life-threatening problem.

See your doctor if you have cyanosis that comes on very gradually, or affects just the fingers, hands, toes or feet. This is usually the result of a less serious problem with blood circulation, but it should still be checked by a doctor.

Why Are My Fingernails Blue?

The medical term for the bluish hue of the skin, including underneath the fingernails, is cyanosis. Blue fingernails can be the result of hypoxemia, an abnormally low amount of oxygen-carrying hemoglobin within red blood cells. Normally, arterial blood is flush with these oxygenated cells, making it appear bright red, but when oxygen levels decline, blood appears bluish red. Cyanosis is an indicator of this deficiency, often first noticed on the lips, gums, around the eyes, and under the nails.

Very cold temperatures can temporarily slow the flow of blood through the skin, also leading to the bluish color, but this typically goes away when you warm up. Blue fingernails or purple nail beds can be a sign of various disorders and should be investigated. In the case of Raynaud’s disease, the fingers and toes blanch on exposure to cold, then turn blue and may become numb or painful. This problem represents oversensitivity of nerves controlling blood flow through small arteries in peripheral areas of the body (fingers, toes, nose, and ear lobes) it may be associated with autoimmunity.

Chronic cyanosis and blue fingernails can also be signs of many different lung and breathing problems, including a pulmonary embolism, asthma, emphysema, chronic obstructive pulmonary disease (COPD), or chronic bronchitis. They also can result from heart problems, exposure to high altitudes, and reactions to certain drugs, such as minocycline (an antibiotic), narcotics, benzodiazepines, and some sedatives. Be aware that taking colloidal silver can also cause the appearance of a slate-blue color just above the lunula (half-moon in the nail bed) and on the face, an irreversible skin condition called argyria.

If blue nails aren’t merely a temporary reaction to cold temperatures, I suggest having a medical checkup to identify the underlying cause. Your physician will probably want to do a simple rapid-blood gas analysis to measure the oxygen in your blood and perhaps some tests to check your heart and lungs.

Blue Fingernails and Exercise

There can be several causes of blue fingernails that result from exercising. Some of the most common include lack of oxygen being pumped by the blood through the heart, abnormal hemoglobin, lung disease and heart disease, explains MedlinePlus.

If your heart is unable to properly pump blood into your bloodstream — especially during a workout, you may first notice the bluish tint to your nail beds. Other medical conditions could also be the cause, such as pneumonia, asthma, pulmonary hypertension and chronic obstructive pulmonary disease.

Exercising in cold temperatures can cause blue fingernails. Warming your hands or massaging your fingers should return your nails to their normal color rather quickly if this is the cause of your cyanosis.

Watch the video: Curved nails 1 year later follow-up (September 2022).


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