Bruises are common, and determining why they are there is usually relatively straightforward. But determining what the bruises of a given child mean can be a challenge. Questions that come up include "What is normal and what is abnormal?", "How many bruises are too many?", "Can bruises be aged?", and "How can accidental bruises, nonaccidental bruises, bruises associated with a coagulation disorder, or lesions that only masquerade as bruises be distinguished?"
A bruise (or contusion or ecchymosis) is a discoloration of the skin without a laceration that is produced by blunt trauma. A bruise occurs when hemorrhage from ruptured capillaries (and small veins), primarily in the subcutaneous tissues, extravasates to produce discoloration. Bruise colors then change as hemoglobin breaks down.1
Bruises are distinguished from purpura by etiology.2 Purpuric lesions are also due to extravasation of blood into the skin but not necessarily because of trauma. Infections, diseases with vascular fragility or vasculitis, and severe abnormalities in coagulation can cause purpura without significant trauma. So, in a strict sense, bruises are purpuric lesions, but not all purpuric lesions are bruises.
Petechiae are also due to extravasation of blood (from capillaries), but are distinguished from purpura by being less than 2 mm in diameter. In contrast to hyperemic skin lesions (where blood remains within dilated vessels), petechiae and purpura will not blanch when overlying skin is stretched.2 Like bruises, petechiae can be caused by trauma, as from capillary sheering forces next to a slap or a swat.
Normal bruises are due to accidental trauma and the severity of a bruise is consistent with the severity of the injury that produced it. Because of this, normal bruises are uncommon before a child begins walking and become increasingly common thereafter, at least until preadolescence.
Sugar et al. monitored the frequency of contusions using 1,001 well-child visits in 7 Seattle practices. They found that, overall, 21% of patients aged 0 to 36 months and with no known medical conditions that predisposed to bruising or suspicion of abuse had 1 or more bruises.3 But only 2 of 366 (0.6%) of the infants younger than 6 months and 8 of 473 (1.7%) of the infants younger than 9 months had any bruises. Overall, only 2.2% of the children not yet cruising had bruises, compared with 18% of the cruisers, and 52% of the walkers. This last group had a mean of 2.4 and up to 11 bruises per child.
Labbe and Caouette studied traumatic skin lesions in well Canadian children and found an even higher frequency: 60% between 9 months and 4 years old, 80% between 5 and 9 years old, and 53% between 10 and 17 years old had 1 or more bruises.4 Again, this contrasted with only 1.2% of those younger than 9 months. Multiple injuries (some combination of bruises, scratches, or abrasions) were not found in this youngest group but were common thereafter, and injuries peaked in spring and summer. Also, these accidental injuries were usually over bony prominences (eg, shins, knees, elbows, or forearms) and were not uncommon on the forehead: 6.4% of those 9 months to 4 years old had a forehead contusion. In contrast, fewer than 2% of all children had skin injuries to the thorax, abdomen, pelvis, or buttocks, and fewer than 1% had injuries to the chin, ears, or neck.
BRUISES CAUSED BY NONACCIDENTAL TRAUMA
Once you know the patterns of normal contusions, it is easy to fill in the blanks for bruises left by child abuse. Significant bruises before a child walks, or bruises on the face (other than the forehead), neck, trunk, back, or buttocks are more likely to be consistent with a nonaccidental injury, unless an accidental origin is known. On the other hand, even multiple normal bruises are not uncommon in older children.
CAN BRUISES BE AGED?
So, how common is it to have multiple bruises of different ages in a given child? And when a child has bruises of different ages, is the source more likely to be nonaccidental? Until recently, the literature assumed the latter was true and many sources still list bruises of different ages as suggestive of abuse. It makes sense that multiple injuries occurring at different times increase the chance that a given child has been abused. But if normal bruising is so common, how often will normal children have bruises of different ages? Neither of the above two studies3-4 tried to answer this question.
Actually, the question goes deeper. Can you date bruises to tell whether a child has been injured on different days? The technique used to estimate the ages of individual bruises depends on color changes. The literature has suggested that bruises are initially red, blue, and black, and transition to brown, yellow, and green in approximately a week.
Although widely accepted, this technique of using color to determine whether a child's bruises are of different ages is flawed.1,5"7 Two recent studies, one for adults and adolescents1 and the other for children,7 observed color changes of ecchymoses from known accidental trauma. The timing of each injury was unequivocal. Both studies demonstrated that color changes with time were not dependable, with the exception that bruises with a yellow color were always more than 18 to 24 hours old. The other colors were too variable to count on for pinning down when trauma had occurred.
I must confess that I used colors to help determine whether a child's bruises were accidental or nonaccidental on more than one occasion. As I remember it, these children had other evidence of nonaccidental trauma, such as burns, scars, and bruises and bruises shaped like belt buckles or straps, so this did not result in false accusations by legal services. Many of us may have overused color to age bruises. I wonder how many other misconceptions we are making like this. We need much more evidence-based research in pediatrics.
DETERMINING WHETHER BRUISES ARE RELATED TO A CLOTTING DISORDER. AND WHEN IS A BRUISE NOT A BRUISE?
This issue of Pediatric Annals provides detailed descriptions of bleeding in children with abnormal clotting mechanisms. But, briefly, plasma defects of coagulation lead to more deep-seated bleeding, with or without trauma, than is found in normal children.8 Hemorrhage into muscles and joints and troublesome recurrent or delayed hemorrhage often accompany skin bruises in these children. The family and medical histories are of great help here as well.
On the other hand, thrombocytopenia (as from idiopathic thrombocytopenia) or platelet dysfunction (as from aspirin) is more likely to be acquired and not familial, plus characterized by more superficial bleeding into skin and mucous membranes. This makes bruising with these disorders more difficult to distinguish from normal or nonaccidental contusions. However, significant mucous membrane hemorrhages will point more toward thrombocytopenia.
Of course, one reason to suspect a clotting disorder is if a child has too many bruises, especially for the degree of trauma, and new bruises (of different ages) keep appearing. The problem here is that these are also reasons to suspect physical abuse. This makes it important to screen for clotting disorders when nonaccidental bruising is suspected. Although such screening is done for legal reasons (to assure the court that no bleeding disease is present), the literature indicates that it is possible to mistakenly diagnose abuse in children with clotting abnormalities.
For example, Wheeler and Hobbs9 described 23 children who were referred for suspected child abuse because of "bruises" and turned out to have something else. Five had mongolian spots, 3 had capillary hemangiomas ("stork bites"), 3 had idiopathic thrombocytopenic purpura, 2 had discolorations from dye, 2 had eczema, and 1 each had hemophilia, hemorrhagic disease of the newborn, prominent facial veins, bruises of "cao gio" Vietnamese folk medicine ("coining" can also produce bruises), erythema nodosum, allergic "shiners," subconjunctival hemorrhage from pertussis, and bruises from a dental treatment. In summary, 5 had dotting disorders, 4 had bruises from a cause other than abuse, and 14 had lesions that masqueraded as bruises.
O'Hare and Eden10 also described 50 consecutive patients referred for suspected abuse, 8 of whom had some evidence of a coagulation disorder: one had low levels of factors II, VIII, and IX due to a temporary inhibiting factor; another had a familial platelet disorder; and a third had von Willebrand disease. Five additional patients had prolonged partial thromboplastic times. On final analysis, all but the first were also diagnosed as having been abused. The causes for the prolonged partial thromboplastin times in the last group were undetermined; at least 4 were transient. The authors speculated that these minor injuries might have led to circulating thromboplastic substances that briefly prolonged their partial thromboplastin times. This definitely occurs in more severe injuries, especially to the brain.
Anyway, the bottom line here is that clotting studies should be routine when child abuse is suspected and bruises are present, as is generally recommended. But a clotting disorder does not mean that the child has not also been abused, and all abnormal findings require follow-up.
1. Langlois NE, Gresham GA. The ageing of bruises: a review and study of the colour changes with rime. Forensic Sci Int. 1991;50:227238.
2. Bolognia JL, Braverman IM. Skin manifestations of internal disease. In: Fauci AS, Braunwald E, Isselbacher KJ, et al., eds. Harrisons's Principles of Internal Medicine, 14th ed. New York: McGraw-Hill; 1998: 326-337.
3. Sugar NF, Taylor JA, Feldman KW. Bruises in infants and toddlers: those who don't cruise rarely bruise. Arch Pediatr Adolesc Med. 1999;153:399-403.
4. Labbe J, Caouette G. Recent skin injuries in normal children. Pediatrics. 2001;108:271-276.
5. Wilson EF. Estimation of the age of cutaneous contusions in child abuse. Pediatrics. 1977;60:750-752.
6. Schwartz AJ, Ricci LR. How accurately can bruises be aged in abused children? Literature review and synthesis. Pediatrics. 1996;97: 254-257.
7. Stephenson T, Bialas Y. Estimation of the age of bruising. Arch Dis Child. 1996;74:53-55.
8. Graboski EF, Corrigan JJ Jr. Hemostasis: general considerations. In: Miller DR Baehner RL, eds. Blood Diseases of Infancy and Childhood, 7th ed. New York: Mosby-Year Book; 1995:858-860.
9. Wheeler DM, Hobbs CJ. Mistakes in diagnosing non-accidental injury: 10 years' experience. BMJ. 1988;296:1233-1236.
10. O'Hare AE, Eden OB. Bleeding disorders and non-accidental injury. Arch Dis Child. 1984;59:860864.