True colors - bruising - includes related articles

Harvard Health Letter, May, 1993 by Ruth Papazian

In emotional terms most of us become thicker skinned with the passing years, better able to shrug off the slings and arrows that in the first decades of our lives would have cast us into a Hamlet-like funk. Unfortunately, our actual skin becomes thinner as our psychic hide toughens, so that late in life it takes far less than a sling or an arrow to produce a nasty-looking bruise.

"When we are young, the cells in the skin are plump, tall, and upright. With age they flatten out," observed dermatologist Marlene Mash, an expert on aging skin. As this happens, the major layers of the skin become thinner and more fragile.

Skin deep

The epidermis is the body's protective outer coating. It is nourished and supported by the underlying dermis, a strong, flexible lattice of fibers that contains many tiny blood vessels, nerve endings, and sensory receptors. Beneath the dermis is a layer of fat that acts as a shock absorber between the skin and the muscles, tendons, and bones below.

The blood vessels of the dermis decrease in number with the passing years and gradually lose the ability to supply nutrients to the epidermis. At the same time, the dermis becomes less springy as its collagen and elastin fibers, which ran parallel to the skin surface in youth, grow tangled, thicker, and more rigid. In the mirror these changes show up as what we diplomatically term "character lines."

More relevant to the matter of black-and-blue marks, however, is the tendency of blood vessel walls in aging, sun-damaged dermis to become thinner and more fragile. This fragility, coupled with the overall loss of cushioning, may cause a bruise to appear after the merest tap, said Dr. Mash, an attending physician at Montgomery Hospital in Norristown, Pennsylvania. Women, in particular, are likely to bruise more easily as they age. This happens because the fall in estrogen production that occurs at menopause speeds dermal atrophy.

Bruising is especially likely to occur in areas where the skin is very thin (such as around the eyes) or where there is little fat to absorb a blow (on the forearm, for example).

Things that go bump . . .

Most bruises are merely colorful nuisances, indicating nothing more an unstoppable force (you) meeting an immovable object (that darned nightstand). But black-and-blue marks that occur with unexpected frequency, or that don,t look the same as regular bruises, may signal the need for further investigation. When geriatrician Kenneth Brummel-Smith evaluates a patient with numerous or large bruises, he looks for the following possible contributors:

* Age-related nerve and muscle deterioration

that makes falling or bumping into things

more likely

* Inherited or systemic illnesses that increase

susceptibility to bruising

* Medications or environmental factors (including

domestic violence) that lead to bruising

People vary widely in their ability to steer clear of sharp corners. "There is tremendous variability in physical strength and agility among people as they age," noted Dr. Brummel-Smith, director of geriatric evaluation and management at the Veterans Affairs Medical Center in Portland, Oregon. Much of this variation probably depends on how active a person has been all along. "By age 70 everyone experiences neurological and musculoskeletal changes that alter gait and balance to make bumping and falling more likely, but inactive people are affected to a greater degree," he said.

Bad blood?

Sometimes bruising is a sign of an underlying ailment rather than the memento of a close encounter with a hard object. "Bruising may be a manifestation of a systemic bleeding disorder affecting platelets [which are involved in clotting] or coagulation factors in the blood," said Bruce Ewenstein, assistant professor of medicine at Harvard Medical School.

Just as the Little Dutch Boy supposedly averted catastrophe by sticking his finger into the hole in the dike, platelets prevent uncontrolled bleeding by plugging the leaks in the walls of injured blood vessels. If not enough platelets are available (thrombocytopenia), or if the available platelets are defective (thrombocytopathy), then even a minor bump can unleash enough blood to produce a visible bruise, explained Dr. Ewenstein. With aging, the bone marrow cells from which platelets are derived become more susceptible to chromosomal damage that can adversely affect the number or quality of platelets produced.

Platelet manufacture may be temporarily or permanently decreased by certain diseases, drugs, or toxins that can act on bone marrow cells. For example, a condition called aplastic anemia can permanently damage bone marrow. Or platelet production may be temporarily derailed by alcohol abuse or treatment with chlorothiazide, a common diuretic drug. Thrombocytopenia may also result from bone marrow malignancies such as leukemia, lymphoma, or multiple myeloma. In these cases widespread bruising may be an important clue that cancer is present.

Sometimes thrombocytopenia occurs because the immune system mistakenly attacks platelets and destroys them faster than they can be made. This may occur following a severe cold or other viral infection, as a result of a systemic disease such as lupus erythematosus or chronic lymphocytic leukemia, or as an adverse effect of medications.