“Skin writing” – aka dermatographism/dermographism

An example of dermatographism. courtesy of Wikipedia user R1carver

For some people, scratching the skin leads to raised wheals, demonstrating dermatographism which literally means “skin writing.” Scratching or stroking the skin leads to redness and a wheal of that area. About 5% of the population develops redness and some swelling of scratched areas — this is called simple dermatographism. In symptomatic dermatographism, these areas become itchy as well and the wheals are more prominent. In general, wheals develop about 5-10 minutes after the scratching but sometimes they can develop after a longer period of time. Your doctor can test whether you have dermatographism by gently scratching your skin (

usually your back) and seeing whether a wheal forms.

If you have dermatographism, try to avoid stimuli like scratching which lead to the discomfort. Antihistamines can also offer symptomatic relief.

Skin tags: benign but potentially unsightly

courtesy of Jkemp wikipedia contributor
Skin tags are more fancily referred to as acrochordon or fibroepithelial polyps (quite a mouthful!) They’re benign outpouchings of skin which aren’t much of a bother except when they get caught on necklaces, bra straps, clothing, etc. or when their presence starts to bother you. They can be skin colored or have some color to them. Often, they’re located around the neck, armpits or upper thigh areas. They can also be found on the face including the eyelids. They are easily treated though by your dermatologist. He/She can freeze these growths with liquid nitrogen, burn them with a cautery device, or cut them off with a scissor or scalpel. Sometimes, some lidocaine anesthetic will be injected before cutting them off. Because skin tags are benign, removal is not considered a medical necessity, so chances are removal will not be covered by your insurance.

What is SPF? SPF = sunburn protection factor

Image courtesy of Wikipedia user Axelv.

One day after Tropical Storm/Hurricane Irene passed through town, the sun is back! Perfect time to learn about sunscreen.

A common question is: what is SPF? SPF stands for sunburn protection factor. (The FDA changed it from sun protection factor to sunburn protection factor as sunscreen does not completely protect you from the harmful UV of the sun.) The number is a measure of how many times more it takes for you to burn with the sunscreen on compared to not wearing the sunscreen. So for instance, if it takes a certain amount of UV rays for you to become red without sunscreen, it would take 15 times that amount of UV for you to become red when you wear SPF 15 sunscreen. The SPF label assumes that you correctly apply the sunscreen. You should use about 1 ounce to cover the surface of your body. Furthermore, you need to reapply the sunscreen as you sweat, or get wet. Additionally, the SPF value on bottles refers to harmful UVB (ultraviolet-B) rays, but not harmful UVA rays. When choosing a sunscreen, look for one that covers UVA and UVB (“broad spectrum” sunscreens).

In the path of Hurricane Irene? Avoid Trench Foot from flooding

courtesy of Wikipedia user Bidgee
Outside my window, Hurricane Irene is certainly making its presence known, dropping plenty of water and flooding streets. Flooding and wet conditions can predispose to a condition called trench foot or immersion foot. Trench foot receives its name from World War I (WWI), where trench warfare predisposed to this condition. Damp or water accumulation in trenches along with the boots that soldiers wore meant that the feet did not have a chance to dry off. This led to water retention by the skin presenting as swelling, pain, tingling, numbness from nerve damage, discoloration and possible blistering of the skin. During Hurricane Katrina, the CDC put out recommendations for the prevention and treatment of trench foot. It’s also important for people affected by flooding from Hurricane Irene to know about this condition. Avoid tight fitting shoes, change wet socks or shoes, and dry the feet when they become wet. Trench foot also makes it more likely for the feet to become infected by bacteria and fungus. If there is any concern that you may have trench foot, you should seek medical attention.

Lime + Your Skin + The Sun = Rash, aka “Mexican beer dermatitis”

Lime is a cause for phytophotodermatitis.
We all know that lime adds a refreshing citrus touch to drinks especially appreciated during these hot summer months. Unfortunately, sometimes some of these lime-containing drinks can spill on our skin and cause a rash after sun exposure. Such cases have been referred to as “Mexican beer dermatitis” since lime is often squeezed into Corona beer. This type of a rash is an example of a phytophotodermatitis. UV rays from the sun interact with an ingredient in the lime on the skin causing redness and blisters. These areas can then darken afterwards. Other causes of phytophotodermatitis include: parsley, celery, parsnip, hogweed, fennel, rue, burning bush, bergamot orange, hawaiian lei flower, fig trees, bavachee or scurf-peas. Now that’s a mouthful!

ABCDEs of Melanoma

I’m frequently asked about what to look for on self skin exams. Here’s a good starting point when evaluating a spot on your skin. Think about the mnemonic ABCDE.

A: Asymmetry
B: Border irregularity
C: Color change or different colors
D: Diameter greater than 5 mm (the size of a pencil eraser)
E: Evolution. Watch for any change.

If you have any doubts at all, have your doctor check your skin!

Squeezing stinky cottage cheese from your skin? It could be a cyst.

Image by Wikipedia contributer Fastily
Recently, someone came in for a large “pimple” that extruded a foul-smelling thick whitish material when it was squeezed. It then would go through several rounds of becoming red, irritated and painful. Turns out she had a cyst. Cysts are fluid filled sacs held by a cyst wall. When the cyst wall is disrupted, the contents inside can cause a reaction within the rest of the skin or it can come out of the skin. When it causes a reaction with the skin, the surface of your skin can get red and irritated and can mimic a skin infection. Most of the time, such cysts are benign and do not need to be removed (there are malignant causes of cysts though). However, if cysts get in the way (e.g. make it difficult to lay down, rub against clothes, etc.) then you might want to get it surgically removed. In this procedure, the surgeon numbs the area up and removes the entirety of the cyst — contents and wall included. Stitches are then placed to close up the skin. If the cyst is drained but the cyst lining is not removed, the cyst can recur.

Notably, cysts can also occur on the scalp. The most common type of cyst on the scalp is called a pilar (aka trichilemmal) cyst. Again, if it gets in the way (e.g. of your pillow, headrest or comb/brush), you can opt to have it removed.

What is a skin biopsy?

Histopathology of melanoma from the thigh
If you’ve been to a dermatologist, the issue of a skin biopsy may have come up. What is a skin biopsy? A skin biopsy allows the physician to make a diagnosis of a rash or a worrisome skin lesion (e.g. when your doctor suspects a skin cancer). It’s a procedure during which a small piece of skin is cut and then sent to a pathologist. A pathologist is a doctor that looks at the cells of the tissue and makes a diagnosis (when possible). A potential order of events is as follows:

1. Your physician explains the procedure and obtains your consent to do the procedure.
2. The area may be photographed.
3. The area is cleaned and numbed with an anesthetic medication. You will feel a prick and some stinging as the medication is injected into your skin.
4. A small piece of skin is obtained either by a scalpel, a special biopsy blade, or by a cookie cutter like device.
5. Depending on how much and how the skin is taken, stitches may be placed. If stitches aren’t placed, bleeding may be stopped by application of certain chemicals or via a cautery device.
6. The area is bandaged.
7. Wound care is reviewed.
8. The tissue is sent to a pathologist to help render a diagnosis.

Step 4 alludes to the different types of skin biopsies. A shave biopsy is usually done with a blade and do not require stitches. A punch biopsy uses a special cookie cutter device to obtain skin. Stitches frequently are placed when a punch biopsy is taken.

Do you have “chicken skin” of your arms and legs?

Image by Irja

A lot of people have rough small bumps of their arms, thighs and buttocks. These bumps can be skin colored or reddish and have unfortunately been likened to “chicken skin” and can feel like sandpaper. They represent a condition called keratosis pilaris. This is a benign condition which is inherited from mom

or dad, but it can prove to be a cosmetic nuisance and can occasionally itch too. There are several things that you can do to get smoother skin over these affected areas. Using a loofah sponge can help flatten and make these bumps less rough. Moisturizers, lactic acid containing lotions (such as AmLactin or LacHydrin), or lotions and creams containing urea, salicylic acid, alpha-hydroxy acids, tretinoin or tazarotene can help as well. This condition is chronic though (there’s no cure) so you do have to keep up with these maintenance measures if you want to keep the keratosis pilaris in check. However, because it’s a benign condition, there’s no medical necessity for treatment.

Does jogging make you itch?

courtesy of Flickr user ceiling
Does jogging make you itch? I remember those mile runs in grade school when my thighs would end up with a strange tingly itchy slightly swollen feeling and covered with faint pink blotches. Turns out that this is a condition called vibratory urticaria. It’s caused by mast cells which get stimulated by vibration to release histamine and other contents. In this case the histamine and contents inside of mast cells leads to itching, swelling and redness. While many people report vibratory urticaria happening with jogging, it can also occur when operating machinery such as lawnmowers, jackhammers, etc. I just have a mild case of vibratory urticaria. Some people can develop more intense swelling or a life-threatening condition called anaphylaxis with exercise. Rise in body temperature itself can also cause urticaria (hives) and occlusion of hair follicles after exercise can cause folliculitis. So there are all sorts of skin conditions that can happen with exercise!