Often referred to as "barnacles of life," "wisdom spots," "age spots," or even mistakenly as "warts," seborrheic keratoses (SK) are the most common non-cancerous growth to develop in association with aging skin. These incredibly superficial growths form from the outermost layer of the skin, the epidermis. And while considered annoying and often unsightly, the seborrheic keratosis may not be so senile after all. A look at a random group of Australians proved SKs are not the sole domain of the mature set. An impressive 23.5% of those between the tender ages of 15-30 years also had at least a single SK. Despite this myth busting info, the statistics support that maturity goes hand in hand with the seborrheic keratosis. By the age of 75, another look at those Australians revealed 100% sported at least one "wisdom spot."

SKs certainly aren't limited to those living Down Under. Similar U.S. studies would suggest that given time, everyone will find an SK lurking on the skin. And by the way, gender plays no favorites; men and women are equally affected.

APPEARANCES CAN BE DECEIVING

SKs vary widely. They can be large or small, single or multiple and come in a multitude of colors. The growths are typically thick and bulky. A hallmark of seborrheic keratoses is their waxy appearance. They literally look as if they have been stuck upon the skin and that a fingernail could be slipped beneath to pull them off. As tempting as this may seem, it is often not possible and certainly not advisable.

Like most other skin growths, SKs can continue to grow over time. There is no way to know how large an SK will become. On the larger end of the scale, most don't exceed the size of a quarter. The majority are far smaller than that, perhaps only a few millimeters in diameter.

The color of SKs range from hues of golden brown all the way to black. Because of the wide color palette, diagnosis can sometimes be tricky. And occasionally a dark black seborrheic keratosis can be mistaken for a melanoma. It is not uncommon for a dermatologist to biopsy a growth suspicious for melanoma and hear the good news that it was a flat, black SK, instead.

Because they rise above the skin's surface, friction or trauma may result in irritation. The SK can develop surrounding redness, tenderness or itching. Sometimes SKs may spontaneously fall off or get snagged off. While infection is always a concern whenever the skin is abraded, irritation or accidental exfoliation does not result in cancer.

WHEREFORE ART THOU?

Seborrheic keratoses can put in an appearance anywhere on the body, but the upper chest, back, neckline and forehead typically grow a barnacle or two. This makes sense since these areas tend to collect sun damage throughout a lifetime.

VARIATIONS ON A THEME

Stucco Keratoses

Barely raised SKs of the lower legs, randomly arrayed like paint splatters upon the skin, are called stucco keratoses. They are often pale brown, grayish or flesh toned. Stucco keratoses most commonly plague seniors. Are these actually warts in sheep's clothing? While it is not thought that HPV (human papilloma virus) has anything to do with the formation of "normal" seborrheic keratoses, in at least a few instances HPV has been identified in stucco keratoses. Is this an instance of clinical misdiagnosis or is it that this virus plays a role in the formation of stucco keratoses?

A British Journal of Dermatology article detailed several variants of HPV detected by PCR (polymerase chain reaction) in the stucco keratoses of a 75 year old man. The skin was fully cleared by the use of 5% Imiquimod Cream applied overnight 3 times a week for 5 weeks. Certainly a treatment worth contemplating when faced with a recalcitrant form of this condition.

Dermatosis Papulosa Nigra (DPN)

Seborrheic keratoses are not a common concern for people of color. However, African Americans tend to develop a variant of SK known as dermatosis papulosa nigra. DPN are so common in fact, that they are considered a normal skin finding. Dermatosis papulosa nigra are small, dark SKs and often hang by a stalk. Most DPNs are found on the upper face, particularly the apple of the cheeks and temples. Like other SKs, there may be a few small growths, on others, multiple large lesions. DPN tend to form earlier in life than isolated SKs.

DPN respond nicely to a very light electrodessication and currettage (burning and scraping). However, I highly recommend that a test area as far from the middle of the face as possible be performed before widespread destruction is attempted. Skin discoloration is a risk associated with this procedure and more likely to develop on darker skin. This post-inflammatory hyperpigmentation can be lighter or darker than the natural skin tone. A hidden test area helps reduce unsightly results if the worst should happen.

The Sign Of Lesar-Trelat

This is an extremely unusual clinical sign combining the abrupt onset of multiple itchy SKs, that are rather uniform in appearance, with an internal malignancy (usually of the gastrointestinal tract/colon). I again stress it's highly uncommon.

I've only seen one patient with a true Lesar-Trelat and it was associated not with a GI cancer, but a lymphoma of the skin. Remember, this is a very acute onset with literally hundreds of SKs popping up in an extremely short period of time and the skin tends to be very itchy and may even turn red. Don't panic as the number of your SKs increases over the years; that's perfectly normal. But should you experience something unusual, it is always advisable to see your doctor. Better to be safe and relieved than miss a diagnosis.

WHY ME?

While the science of medicine has not discovered the reason why SKs develop, several studies provide insight into potential triggers. Could sunlight be a cause? There is no question that SKs more commonly arise on sun exposed skin. Seborrheic keratoses forming in sun drenched areas tend to be larger and more numerous than those arising in zones hidden from the light of day. And even more fascinating, an increased rate of SK formation is now being seen which parallels the increase in the rate of skin cancer. So it seems that sunlight may indeed play some as yet unknown role in anyone genetically predisposed to the formation of SKs.

Genetics most definitely plays a role for those who grow more than their fair share of seborrheic keratoses. While some of us worry that we've inherited our mother's thighs, our father's nose or our grandmother's thin hair; I for one have long wondered if SKs would be the bane of my skin's existence. Let's just say the maternal side of my family leaves much to be desired in this realm. So far so good, but by the tender age of 26 I'd already developed my first SK.

GROWING PAINS

So what is it genetically that contributes to the formation of these nuisance growths? It's long been recognized that hormones must play some role in stimulating the growth of SKs. Any woman who's been pregnant will know that this is a time when any number of unwanted skin growths suddenly sprout. Whether it's a skin tag, a cherry angioma or an SK, pregnancy is a time when more than one's tummy is blooming. During pregnancy, a natural rise in estrogen, growth hormone and epidermal growth factors (EGF) occurs. If skin cells have a higher number of receptors or are more easily "turned on" by the presence of these hormones, then perhaps one or more are the culprit.

Think of receptors as the lock; the hormone or growth factor as the key. Once the key is placed into the lock, some type of reaction occurs within the cell to set off a reaction. A simplistic example: fill the EGF receptors with epidermal growth factor and watch the cells multiply.

Vanderbilt University evaluated the presence of EGF receptors in women who were pregnant or taking sex steroid hormones. Their findings showed that receptors increased in number in growing SKs and skin tags vs. those growths evaluated in other patients.

EGF receptors are also known to have an altered distribution in many skin concerns including psoiasis. In a separate Vanderbilt University study, seborrheic keratoses and skin tags were again evaluated; this time to compare the presence of receptors in actively growing SKs and tags vs. viral warts. They found that the presence of these receptors was indeed increased in actively growing lesions and not uniformly seen in other skin disorders such as warts or molluscum. Were these receptors already genetically predetermined to be there in greater numbers or did something else cause them to suddenly multiply?

The role of other growth factors are precisely entwined in a complicated and still not fully understood fashion. A family of growth factors known as transforming growth factor (TGF-beta) regulates the growth of cells and their differentiation. In the International Journal of Oncology 1999, the effects of TGF-beta 1 and other factors were evaluated upon a variety of skin growths (SKs, actininic keratoses, basal cell carcinomas and squamous cell carcinomas). They found that SKs have a higher TGF-beta 1 receptor concentration compared with squamous cell carcinomas (a form of skin cancer). And perhaps something environmental was changing the amount of receptors present or altering their ability to respond to the hormone TGF-beta 1. Resistance developed in the cells that became cancerous versus those which remained benign yet multiplied to form some other type of growth. "Conversion of normal keratinocytes to tumorigenic cells may in part be due to an acquisition of resistance to TGF-beta and loss of expression of intracellular signaling Smad proteins."

Suffice it to say that growth factors and hormones do play a vital role in the formation of seborrheic keratoses and that with time the intricacies of this chain of events will be better understood. Knowing the precise way in which these growths are triggered will provide insight into how best to treat and better yet, prevent them in the first place.

BLAST OFF

Until science offers a better way, the treatment of SKs remains somewhat limited. Understandably most patients dislike the looks of these warty bumps and want them removed.

Unfortunately, there is no preventative therapy for seborrheic keratoses. No cream or pill exists that will keep seborrheic keratoses from forming. The beauty of treatment for the SK lies in its superficial residence on the epidermis. Treatment is aimed at peeling off the growths in some manner. Cutting and stitching is reserved for biopsies when diagnostic confusion arises when the spot clinically is indistinguishable between SK and melanoma.

The most common method to eradicate SKs is the use of liquid nitrogen. This icy cold liquid can be applied with the use of a spray gun (personally I find this more effective) or a Q-tip. When innumerable SKs are present, the spray gun also helps to treat far more growths much more quickly.

Liquid nitrogen can have a stinging, somewhat burning sensation. The treated area will be pink and puffy for a few days. Sometimes a blister or a scab will develop. The treated seborrheic keratosis typically falls off within 2-4 weeks. Sometimes a second liquid nitrogen treatment is required to eliminate it, especially when dealing with a large or especially thick SK. Once an SK is gone, it usually doesn't regrow, but there's certainly no guarantee. And don't forget, if you're prone to forming SKs, more than likely the odds are with you that others (perhaps in another area) will spring up periodically.

Currettage, literally scraping the SK off, is another method of removal. The area is locally anesthetized and the SK is pulled off the skin, often incorporating the use of electrocautery (burning the base of the growth. As this method is somewhat more invasive, I usually reserve it for very large, thick isolated lesions. This also isn't a method that lends itself easily to removal of multiple SKs.

Both liquid nitrogen and currettage can potentially result in some remnant skin discoloration and if a deep freeze or scraping is performed, a scar as well. Proper liquid nitrogen use ideally will be well tolerated and leave minimal surface skin changes. A common outcome may show a bit of brown skin color from the SK itself.

After either procedure is performed, no maintenance therapy short of wound care (if needed) is required.

As SKs are so superficial, the idea of trying to use exfoliants has been tried with mixed results. Potent lactic acid and glycolic acid creams may help smooth out or help exfoliate smaller growths. Ammonium lactate (prescription LacHydrin or OTC AmLactin as well as AHA 20 can help the hardened growth to soften and then shed partially or fully.

Chemical peels may be considered in more generalized, smaller SK situations. A series of medical microdermabrasions may help with smaller stucco SKs or newly forming minute papules.

While I have seen Retin A and Tazorac prescribed for some patients, I have not been as impressed with their results on SKs. However, both Renova and Avage (the forms of these active ingredients with FDA approved photodamage indications) can certainly help rejuvenate the skin and address underlying photodamage. And since we presume the sun has some bearing upon the formation of many of these growths, it can't hurt to use for those reasons. However, do not overuse and cause irritation. I have seen over aggressive use by patients in a hurried attempt to free themselves from their barnacles and all that happened was unpleasant redness, tenderness and irritation.

Treatments I have read about in literature searches but not tried include the topical use of Solcoderm, a copper ion and acid mixture. This is not available in the U.S. It essentially causes treated areas to scab and exfoliate over a period of 2-3 weeks. It sounds similar to chemical peels with the use of trichloracetic acid, which is available in the United States.

Northeast Ohio Universities College of Medicine recently published an article in the Journal of Dermatology Surgery that showed excellent cosmetic results with the use of the Alexandrite laser when treating numerous SKs at once. Like liquid nitrogen and curettage, this is a destructive therapy. Sounds great, but lasers remain somewhat costly in many areas of the country. If you're interested in this, call around and make sure that you are in the hands of a qualified laser surgeon.

Finally, a Japanese group of researchers from Yamaguchi University School of Medicine published an article on the benefits of an oral Vitamin D3 derivative, 1,25-dihydroxyvitamin D3 (1,25(OH)2D3) in the treatment of seborrheic keratoses. Approximately 2 weeks into treatment the smaller SKs darkened, crusted and began to fall off.

Do NOT start popping excessive Vitamin D in a home remedy attempt to replicate this! It's not what was used and you may end up overdosing on the vitamin. However, it is interesting to wonder if the use of a prescription Vitamin D derivative such as Dovonex (used to treat psoriasis) would offer any benefit in the treatment of these lesions. This would be an off label use and I've never tried it, but it's always fun to think through the possible benefits.

CHARGE IT

It may seem unfair, but it's important to know in advance that your medical plan may not cover the removal of seborrheic keratoses. Certainly if there is any question regarding the true diagnosis of the growth, a biopsy should be a covered benefit provided you've met all the requirements provided in your particular plan. But when it comes to anything even remotely considered "cosmetic," most medical insurance companies have changed their coverage drastically.

They followed the lead of Medicare, which declared the removal of most benign growths "non-essential" (cosmetic), and thus a non-covered benefit. A few stray plans still offer coverage. Check with your particular insurance company and always try to get it in writing. If you find yourself footing the bill, the cost should not be overwhelmingly high. Removal of multiple SKs in a single session should fall somewhere in the $150.00 range. Don't be shy; ask your dermatologist the price before the spraying (or other treatment) begins.

There's just no way around it. Nature has predestined everyone to find an SK or two at some point in time. But with age comes wisdom, and now that knowledge can be put to good use to get rid of those "wisdom spots."

Thank you for taking the time to read my newsletter. I hope you have found it informative.

Audrey Kunin, M.D.

(Any topic discussed in this article is not intended as medical advice. If you have a medical concern, please check with your doctor.)

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