Can skin blanching help diagnose rash severity

Can skin blanching help diagnose rash severity

Skin blanching is a simple, non-invasive, and inexpensive way to diagnose acute skin conditions and rashes. It has been used for many years by emergency room physicians as a way to classify the severity of contact dermatitis and other rashes. Skin blanching measures the loss of blood flow in the skin beneath your fingernail when you press down on it. Your doctor can use this test as part of an overall evaluation of your rash symptoms and how they relate to each other (known as “signs”). This may help them determine whether or not any additional diagnostic testing is needed.

What is skin blanching?

Can skin blanching help diagnose rash severity

Skin blanching is a physical phenomenon that occurs when the skin is exposed to pressure and then released. When the pressure is applied, the blood vessels in the superficial layer of the skin (the dermis) are compressed and some blood is forced out of them into the surrounding tissue. When this compression is released, some of this blood returns to its normal position along with some extra fluid from nearby capillaries. This results in a pale area at first which quickly becomes redder as more blood returns to its normal position.

What causes blanching of the skin?

Can skin blanching help diagnose rash severity

Skin blanching is a sign of vasoconstriction or the constriction of blood vessels. When you pinch your fingers together and they turn white or become paler in color, this is an example of skin blanching.

The skin is a sensitive organ, and when it comes to identifying issues with your health and wellness, it can be an invaluable tool. One of the most obvious ways that we see this is through blanching. This occurs when capillaries constrict—that is, they become smaller in diameter. When this happens, blood flow decreases and so does our oxygen supply.

When we see blanching on our skin, it’s usually caused by either inflammation or vasoconstriction (the narrowing of blood vessels). Inflammation can come from an infection or an allergic reaction; it causes redness and swelling in the affected area. Meanwhile, vasoconstriction refers to situations where the body’s response draws blood away from certain areas of the body—often as a protective measure against frostbite or shock—and into others (like fingers).

The skin’s ability to blanch can be helpful in diagnosing rashes and other inflammatory conditions like sunburns, which are caused by vasodilation (dilation) in capillaries throughout the body. The capillaries dilate as part of an inflammatory response that brings immune cells into contact with pathogens like viruses or bacteria. When your doctor performs a physical exam on someone with an inflamed rash, she might ask them to hold their hand up for 90 seconds while she assesses whether it has turned pale due to vasoconstriction – this would be an indication that he/she has inflammation somewhere nearby (on his/her body).

Can skin blanching help to determine rash?

Skin blanching is a sign that the skin is not getting enough oxygen. When you press on an area of your body and it turns white, this is an indication that the blood vessels in that spot are constricted (narrowed). This happens because there is too much pressure on the blood vessels, so they close up. By pressing down on a particular part of your skin and observing how long it takes for it to regain its color after being released from pressure, you can determine whether or not this area has been affected by a rash.

Rashes can affect many different areas of your body; however, when a rash causes blanching in only one area (such as just around your nose), then it may mean that another condition such as rosacea has developed due to irritation caused by heat exposure or chemicals used during work processes involving high temperatures such as welding materials together or soldering electronic parts together in order to make them function properly again after repairs from rashes were made.

How is blanching of the skin diagnose rash severity?

Blanching is the result of vasoconstriction. The intensity of a rash can be determined by how deep blanching occurs in the skin. When you rub your finger over sick skin, it will turn white for a moment before returning to its normal coloration because blood vessels near the surface constrict and close down temporarily, preventing any blood flow to that area. The deeper this effect extends into the skin layers, the more severe your rash is likely to be.

Your doctor may also use blanching as a diagnostic test for infectious diseases; if blanching occurs upon rubbing a suspect area with an antiseptic swab (as opposed to non-infected areas), there’s a good chance that infection is present in that particular body region.

Read Also: Five Minute Skincare Habits

How is blanching of the skin treated? 

If you’re dealing with a skin rash, it’s important to know how to treat the symptoms. There are several remedies that may help with rashes:

  • Use a cool compress on the affected area of skin rashes. This can be done by soaking a washcloth in cold water and then applying it directly to your skin for several minutes at a time, or by placing ice packs directly on your skin. Can skin blanching help diagnose rash severity
  • To deal with skin rash take an antihistamine pill or other medication( should only be used under medical supervision) be taken under that contains diphenhydramine (the active ingredient in many over-the-counter allergy medications). These medications block histamines from being released and will therefore reduce blanching symptoms as well as itching associated with allergies. Can skin blanching help diagnose rash severity
  • Apply a topical steroid cream or ointment if your rash does not improve after trying other treatments for one or two weeks. Steroids reduce inflammation caused by allergies and can help relieve itching caused by rashes such as eczema; however, they should only be used under medical supervision since they can have serious side effects if used incorrectly.
  • Can skin blanching help diagnose rash severity


Skin blanching is an essential part of the exam to help diagnose a rash. By gently pressing on the skin with a tongue depressor and looking at how quickly it returns to its normal color, you can get a good idea of how serious the rash is. If it blanches quickly or not at all, there may be deeper tissue involvement than just superficial epidermal cells which would require further investigation and possible treatment to get rid of the rash.


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