The last chapter was about mechanical injuries to the skin from sharp or hot objects. The skin can be injured in other ways. Rashes fall into that category too, if you think about it. They represent the skin’s response to a wide variety of noxious things, ranging from infections to poison ivy, insect bites, or a particular brand of soap.
Children get a lot of rashes. There are several reasons for this. One is that children, compared with adults, have very sensitive skin that can be easily irritated by things in the environment. Another reason is that children get relatively more viral infections than adults do, and viral infections are a common cause of rashes.
Very few rashes require a trip to the emergency department; many do not even need a trip to the doctor’s office. However, there are a few important exceptions to this general rule. Mixed in among all the rashes children get are a few that are signs of serious illness, and these should be evaluated promptly by a doctor. Fortunately there are fairly easy ways to identify these more-serious situations. This chapter will tell you how physicians evaluate rashes and what makes us suspicious that a serious problem may be present. The chapter will also tell you about many of the common rashes of childhood—helpful information for any parent to have.
One of the interesting things to know about rashes is that evaluation of them is one of the last areas of medicine to resist the invasion of diagnostic tests and scans; we mostly diagnosis rashes the old-fashioned way—by looking at them and often feeling them with our fingers. Certain rashes do lead us to do some tests because we know those particular rashes are often associated with other problems. But those things are generally secondary to making the diagnosis. The key thing is just looking at the rash and interviewing the parent to get some information about how and when the rash started.
Doctors divide rashes according to a set of categories. Some of these are based upon what the rash looks like, others relate to what the cause is. These distinctions have fancy names that it is not worth your while to read about. But some of the attributes that define the categories are useful for a parent to know because understanding them will help you decide what to do with your child if she has a rash. They are also helpful categories because it will allow you to describe the rash over the telephone or tell a doctor more precisely how your child’s rash may have evolved over time.
The first category concerns color. Most rashes are reddish-colored to some degree. That is because inside the individual rash spot there is usually a component of inflammation, and inflammation makes red blood cells gather in the tissue from the skin’s tiny blood vessels. So the area is pink to red-colored. Of course the color of the rash depends to some extent upon the underlying color of the skin. So if your child has a dark complexion, the red color will be less obvious. A few rashes are purple-colored rather than red. They look like tiny bruises because, in effect, that is what they are—areas of the skin where the smallest blood vessels have broken and are oozing blood into the skin.
Some rashes are flat on the skin; if you close your eyes and run your fingers over them you cannot tell they are present because there is nothing to feel. Other rashes consist of small bumps you can feel above the skin surface. Sometimes the bumps are solid, and at other times they may have little fluid-filled caps on top of each bump. The fluid, if present, can be clear or cloudy. These caps can break open and weep the fluid out onto the skin. When the fluid dries, it leaves a crust, which is why these kinds of rashes often have scaly, crusted areas.
There is also size to consider. Some rashes consist of tiny spots, others have larger blotches or a mixture of sizes. Often the rash spots stay in one location, but sometimes a rash can seemingly magically move from place to place on the body over a short span of time. A series of tiny spots may coalesce into larger spots or blotches.
Finally, rashes vary in what symptoms they cause the child. From a practical standpoint, the main distinction for us is between rashes that itch and rashes that do not itch. A few hurt when you push on the involved area, but not many.
When a doctor looks at a rash, she is running this descriptive catalog through her mind because what the rash looks like, accompanied by a conversation with the parent, is the main criteria she will use to decide what the cause is. A parent can easily learn a few of these principles and put them to good use.
The majority of rashes in children are small red spots that do not move anywhere, do not have any fluid on the top of each bump, do not hurt, and do not itch. The chest and abdomen are common locations. These kinds of rashes are often caused by viral infections. If your child has a rash like this, a clue would be the presence of other symptoms of a virus, like fever, vomiting, or diarrhea. Sometimes, though, a rash like this just comes out of the blue without any other symptoms. What should you do about it? The answer is little or nothing. You certainly do not need to trek into the emergency department unless your child is ill in some other way that would bring you to the hospital even without the rash. If the rash is sufficiently itchy to bother your child, you can apply an over-the-counter anti-itch cream, such as hydrocortisone. But most of the time no therapy is needed.
We also commonly see this sort of rash if a child is having a reaction to a medication. Any medicine can cause a rash, but amoxicillin and its cousin Augmentin are notorious for doing it. Both these medicines are commonly prescribed for ear infections. Since ear infections are common as well, being the most frequently diagnosed condition in children, doctors encounter this rash frequently. Several other oral antibiotics also cause rashes. So if you see a rash suddenly spring up on your child, recall any medicines he has recently taken. If your child gets a rash like this and is taking a prescribed medication, particularly an antibiotic, call your doctor to see if he wants to make any changes in your child’s medications. We do not always change the medicine, however, since in some cases the rash fades away even if the child continues to take the medicine.
Another common childhood rash is hives. This kind of rash is quite different from the first one, even though hives can be caused by a reaction to a medicine. Hives are nearly always a reaction to something in the environment. Once in a while this is a germ of some sort, but usually it’s something the child ate, breathed in, or touched.
Hives are larger in size that the first rash I described, ranging anywhere from a half-inch or so to over an inch in size. They usually are pinkish in color, rather than red, and they swell upward from the skin and make a bump. They often move around; new ones appear and old ones fade as quickly as over the course of an hour. Most importantly, hives usually itch. The prototype for what a hive looks like is an insect sting. Although most hives do not hurt like a bee sting, that is what they look like.
Hives are caused by a different mechanism than the first rash you read about—the small, red spots. Hives are caused by the release into the skin of a substance called histamine. The skin is full of special cells that contain this material and are primed to release it when triggered by something. Histamine makes the blood vessels of the skin leak fluid, which is where the swelling comes from. Histamine triggers the itching too. Often you can just ignore the hives and wait for them to pass, but sometimes they are important to treat, even in the middle of the night.
The most important consideration is if the hives are accompanied by any problems in breathing, such as wheezing. You can judge such problems using the same criteria you learned in chapter 5 about breathing troubles. Of most concern is the rare situation in which the hives occur inside the mouth, causing swelling in the back of the throat or tongue. This situation needs prompt attention in the emergency department. If there are any breathing problems at all, a 911 call is indicated.
We treat hives with one or more of several medications that improve the itching symptoms and make the hives shrink. Diphenhydramine (Benadryl, many others) is available over the counter and is quite safe. It comes in both liquid and capsule form, and the appropriate dose for your child is on the container. If the hives are severe enough to affect breathing or cause airway swelling, we use several injectable medicines in the emergency department. Ambulance paramedics also carry these medications if your child is having breathing problems.
Another common, itchy rash is contact dermatitis. This rash is red, sometimes raw-appearing, and may have small blisters. Contact dermatitis is caused by something irritating the skin, such as poison ivy exposure. Diaper dermatitis in infants and toddlers is caused by irritation of the skin around the groin area; this one may be complicated by having the raw skin secondarily infected by germs, typically yeast.
There are some skin infections that look like rashes. The most common one is called impetigo. It is usually caused by the same germ that causes strep throat. This bacteria can sometimes be found on the skin, and when present it can invade through the outer layer of the skin if that layer gets disrupted in some way, such as by scratching. Strep germs can also make their way into apparently normal skin. The places this frequently happens are portions of the skin that are chronically moist because the wetness can disrupt the skin enough to let the bacteria inside. This is one reason why the most common place to find an impetigo rash is around the corners of the mouth, on the chin, or under the nose. Impetigo is also common in places where the skin is irritated or dried out, both of which interfere with the skin’s normal barrier function. If the strep is there, or is under a child’s fingernails from touching another infected area, scratching introduces the germs to a new spot.
Impetigo has a very characteristic appearance, and you can tell what it is just by looking at it. I have met many experienced parents who are just as good as doctors at recognizing it. It is highly contagious, as are other kinds of strep infections, which is why teachers usually do not want a child with active, untreated impetigo at school. What it looks like is a cluster of crusted, flat, irregularly shaped spots up to a quarter-inch or so in size. The textbook appearance of the crust is honey-colored because it consists of dried tissue-fluid that has oozed out of the infected spot.
An impetigo infection needs to be treated with antibacterial agents. Extensive clusters of sores can be quickly and effectively treated with oral antibiotics. Less-extensive impetigo can be treated with local care and cleaning of the area. You can wash the sores with an antibacterial soap and then put on a thin film of antibiotic ointment, which is available over the counter. If this does not take care of the problem, you can bring your child to the doctor for an antibiotic prescription. Either way, impetigo never requires a nighttime trip to the emergency department.
Strep can cause another fairly common rash, only in this case the strep is not directly infecting the skin but rather is provoking a reaction in the skin. This rash resembles the first variety of rash you read about, red bumps, only in this rash the bumps tend to be very small. The skin often feels like fine sandpaper when you rub it. This rash favors the chest, upper arms, and folds of the skin inside the elbows. The name we give the rash is scarletina. It is also called scarlet fever, a term that provokes fear, especially in grandparents, because a century ago scarlet fever was a deadly disease. This is no longer so, and we do not understand why that is—perhaps the strep germ changed in some way. But whatever the reason, scarlet fever these days just means a rash with a strep infection, typically of the throat.
There is a another skin problem germs can cause, only this time the germ is usually staph, which you learned about in chapter 9. This germ causes many sorts of infections, some of them serious. It often lives on the skin, where it causes no problems. As with strep, however, if there is a break in the skin, the germ can quickly take advantage, crawl inside, and set up shop. You often see staph as the culprit in infections around a splinter or cut. As we’ve seen, though, it can invade the skin without an obvious break in the barrier, such as down a hair follicle. When that happens, we call the tender, swollen, and often red result a boil.
Staph is notorious for making pus, so it is common for a boil to come to a head and drain. That often is sufficient to cure it, since the body’s natural defenses can then take over and clean up the situation. Large, tender boils, however, often need antibiotics to clear them. They also may need to be lanced to let the pus out. Of course both of those possibilities require a trip to the doctor, but as with impetigo, there is no need to do that in the middle of the night.
Although several of the rashes we have discussed so far need medical attention, none of them require a doctor’s immediate attention, with the exception of hives complicated by breathing troubles. However, there is one particular rash that needs prompt evaluation because it can be an indication of more-serious problems. This rash has the medical name petechiae (pronounced puh-tee-key-eye).
Petechiae are caused by a disruption in the tiny blood vessels in the skin, the capillaries—they break and ooze a little bit of blood into the tissue around them. The result looks like little purple-red blotches, typically only a millimeter or so in size. You cannot feel them, you can only see them.
A few petechiae can be normal, especially following some predictable scenarios. You can give yourself a couple of them if you apply a strong suction to an area of your skin; the suction pops some of the delicate skin vessels. Anything that raises the pressure in the tissue can bring on a few petechiae. For example, if a person has had a strong bout of vomiting, it is common to see petechiae in the face or neck, but especially around the eyes. If you put a tight band around your upper arm, you might see petechiae on your forearm because the back pressure from the band disrupts some of the delicate skin vessels.
The petechiae that are important are caused by a somewhat different mechanism. It still is a problem in the tiny vessels, but it is not because of pressure in the tissues. Rather, it is because the vessels have ruptured on their own. The cause is from a disorder of those tiny blood particles called platelets. Platelets are far smaller than cells. They are bits of cellular dust found throughout the circulation. There are a lot of them, about a billion in each teaspoon of blood.
Platelets have several jobs in the body, one of which is participating in blood clotting. If you do not have a sufficient number of platelets, you will be prone to tiny, spontaneous bleeds in the skin following the disruptions that come from normal wear and tear of the small vessels. A platelet count can be low for one of two reasons: either the body is not making enough platelets, or they are being consumed faster than the body can make them. Serious infections can consume platelets, making them clump, and in the process causing petechiae to form. There are other conditions in children that remove platelets from the circulation and lead to petechiae. These conditions are not as immediately concerning as those serious infections, but they still need a doctor’s evaluation.
If your child’s body has petechiae in many places, this does not mean you should necessarily go to the emergency department. But if there are other significant symptoms, particularly fever and lethargy, then you should do that. If your child with petechiae feels well and looks otherwise well to you, the best thing to do is to call your doctor for advice. The odds are high he will want to see your child fairly soon for an evaluation and blood tests, the most important of which is a blood count that includes the platelets.
We have talked about some common causes of rashes in children, but there are hundreds of possible causes. The overwhelming majority of them are not serious. They may cause a child discomfort, but we have ways of relieving those symptoms, and some of them may need a doctor’s evaluation at some point. But very few of them call for a trip to the emergency department. Now that you know something of how doctors think about rashes, it is time to turn to our specific scenarios.
Your second-grade daughter has an itchy nose. She has had a bit of a runny nose for several days from a cold, and she has been diligently blowing her nose as she has been taught. But after a few days of this, her nose is red and raw. It itches, so she has been rubbing it frequently. Now you notice that about a half-inch below her nostrils there is a scabby-looking spot that she has picked open several times. When you look closely at the area, you see some amber-colored, crusting spots oriented as satellites around the bigger scab she has been picking at. What is this, and what should you do about it?
What you are looking at are typical impetigo sores. Under the nose is a very common place to see them, another being just outside the lips. There are not very many of them in this case, and most likely you can take care of these at home and then keep an eye on them to make sure they resolve. First wash the area with soap and water. Then put a thin film of antibiotic ointment over the sores. Repeat that at least twice each day until the sores go away. It is important to have your daughter wash her hands frequently to remove any strep germs that are lurking there. Also cut her fingernails short so any scratching she does is less likely to break the skin. If the sores persist or spread, you can call your doctor or bring your daughter in for evaluation.
Your ten-year-old son has come home at the end of a July day spent on a friend’s farm. He is dusty and grimy. He also is itching his thighs and upper arms nearly constantly. You see that he has about ten or twenty raised bumps in those areas. The bumps stick up above his skin surface perhaps a quarter-inch or so. Surrounding several of them are red, blotchy areas that form a sort of halo. The ones he can reach have scratches on them from his itching. He otherwise feels fine. What is this and what should you do about it?
This child has typical hives. This case is instructive because much of the time we have no idea what the inciting trigger was. This child has spent a windy day in an environment outside his usual one with multiple potential hive-makers such as grasses and other plants, dusty barns, and animals. The only way to get any clue about what did this is to see if it happens again and then do some detective work. For this episode, the important thing is that he has no swelling in his mouth, difficulty swallowing, or breathing troubles.
If this were your child, you could do a couple of things to make him feel better. First, get him out of his clothes because whatever is inciting the hives could be lurking there. Then wash him off in a bath or shower for the same reason. You can help his itching by giving him some diphenhydramine (Benadryl, many others), which you can get at any pharmacy and most large grocery stores. The medicine will block the histamine that is producing the hives and making him itch. It will also make him drowsy, which at this point in the day is probably a good thing.
We can modify the above scenario just a little to make calling for advice a good plan. Let us say your son has many, many hives. He still has no airway swelling or breathing troubles, but the itching is driving him crazy. You have given him a dose of diphenhydramine, but it does not seem to have helped very much.
In such a situation, it would make sense to call for advice. We have other medications to block the hive process that are more powerful than diphenhydramine. Your doctor may want to consider prescribing one of these, or he may tell you to increase the diphenhydramine dose.
Your one-year-old was diagnosed a few days ago with an ear infection after having fever for a day. He is taking amoxicillin (Amoxil, many others), a commonly prescribed oral antibiotic for this problem. Today he is better. His fever is gone, he is eating normally, and he is acting totally himself. But while putting him to bed you notice his chest and abdomen are covered with tiny red bumps. The rash does not seem to be bothering him at all. For example, he is not itching anywhere. What should you do about this?
The answer to this scenario is that his rash is most likely from the antibiotic. Although almost any medicine can cause a rash, amoxicillin is notorious for doing this. If your son has no other symptoms than the rash, he does not need to be seen by a doctor. However, depending on how far along this child is in his antibiotic course, many doctors would want to change the antibiotic to another one to complete his treatment for the ear infection. The best thing to do in this scenario is to call the doctor to ask for advice.
Your three-year-old daughter has had upper respiratory infection (URI) symptoms for a week or so, but she has otherwise seemed herself. She has had no fever, and she does not seem to have any aches or pains. Today she has a rash. The rash feels flat on the skin and consists of tiny purple spots—the petechiae you read about earlier. In a few places, the petechiae are merging with each other to make larger purplish splotches. It is early evening on a Friday and you wonder what you should do. Can this wait until Monday, or should you have her evaluated over the weekend?
If this were your child, the best answer to this scenario is you should take her to the emergency department. Your daughter may have a problem with her blood platelets, such as having too few of them circulating in the blood. There are several possibilities for the cause of a low platelet count, but all of them are potentially serious and cannot wait. The doctor can do some simple tests, especially a blood count, to identify the likely problem. Your daughter may need further, more complicated tests to determine what is wrong, and she may need to come into the hospital for treatment.
This child has a not-uncommon condition with the tongue-twisting name of idiopathic thrombocytopenic purpura, or ITP for short. Translated into English, each of those words describes the condition: idiopathic means we are not sure what causes it; thrombocytopenic means low platelet count; and purpura is the fancy name for those purple blotches from coalescing petechiae.
The disorder is the result of a child’s immune system attacking her platelets and removing them from the circulation. The platelets are sequestered in the spleen, an organ in the upper left part of the abdomen. When you examine a child with ITP, you typically feel the resulting enlarged spleen. We have effective treatment for ITP, and in most children the condition resolves with this treatment, leaving the child healthy again. But it is best to begin this treatment, which generally takes a few days in the hospital, as soon as the disorder is identified.
The URI symptoms in this scenario do not have anything to do with the ITP. I just put those in to remind you that situations are often complicated. It is hard to know sometimes if symptoms are related to each other or are just a coincidence.
Your eight-year-old daughter has had a fever as high as 104 degrees all afternoon. She has not complained of anything in particular, but she feels a bit weak and dizzy. In the evening you notice she has a rash on her arms and chest. At first the rash looks like small bites—tiny reddish-purple spots. Over the next couple of hours the rash spreads and the spots seem to be getting a little bigger. She still has a temperature of 104 degrees. What should you do about this?
This child’s petechial rash is different from that of the child with ITP for a couple of reasons. For one thing, it is progressing much more rapidly. For another, this child is quite ill, with fever and disorientation. That symptom has also progressed quite rapidly. In this case, the petechiae are from a serious, life-threatening bacterial infection. This infection is in the bloodstream, and one of the consequences of the infection is that it consumes platelets. It does many other things too, such as causing the fever and lethargy, but the rash you see is from the destruction of platelets.
This child needs emergency medical attention, which will include blood tests and intravenous antibiotics. She may well need other kinds of therapy as well, depending upon how rapidly the infection is spreading and whether it affects other organs in the body besides the skin, which it nearly always does. Taking your daughter to the emergency department would be the best thing to do in this scenario.
The bacteria that most commonly causes symptoms like these is called Neisseria meningitidis, or meningococcus. It is contagious. Anyone who has close contact with a documented case should receive oral antibiotics to protect them from contracting the infection. There is also a vaccine that prevents many, although not all, forms of this infection. The American Academy of Pediatrics now recommends that all children receive this vaccine when they are eleven or twelve years old, with a booster vaccination at age sixteen.
In this scenario we modify the story above in a key way. As the rash progresses, becoming more extensive and coalescing into larger purplish blotches, the child’s level of consciousness is also changing. She is becoming progressively more lethargic and has spent the last three hours asleep on the couch. When you rouse her she seems incoherent, and you are not sure that she even recognizes you.
This scenario is best handled with a 911 call for help. Things are moving along quickly, and the paramedics will know how to handle the situation. They carry various medications that may be needed to get the child’s treatment started.
The great majority of childhood rashes do not need a trip to the emergency department—most can safely be watched at home. There are a few important exceptions, however, and if you are unsure of what to do, it is a good idea to call your doctor for advice. Since we have discussed several things you can do yourself with some common rashes, this chapter modifies the “Watchful Waiting” category a bit.
Your child appears generally well except for the rash. A mild fever may be present, but not much else.
The rash looks like simple impetigo: crusted sores around the mouth and nose. (You may treat this with antibiotic ointment.)
The rash looks like simple hives, and your child has no breathing troubles or swelling of the lips or tongue. (You may treat this rash with diphenhydramine [Benadryl, many others].)
Your child has an impetigo rash that is not improving with home therapy.
Your child is taking a new medicine, such as an oral antibiotic.
Your child has a progressive diaper rash that is not improving with ordinary lotions and creams.
Your child has tender skin boils.
Your child has hives accompanied by shortness of breath or swelling around the lips or tongue.
Your child has a generalized petechial rash.
Besides having the rash, your child appears ill with other symptoms, such as poor oral intake and high fever.
Your child has hives with severe breathing troubles, such as severe wheezing or severe swelling in and around the mouth or throat.
Your child has a petechial rash and is disoriented or otherwise appears severely ill.