It’s cold and flu season and around this time of year I start seeing parents in my office concerned that their child is “always sick,” and that there must be something wrong with their child’s immune system or that they have a “low immune system.” I don’t doubt these parents when they say that their kids are always sick. As I mentioned in a previous post:
“The average child experiences between 6-10 viral upper respiratory infections a year. The average duration of each cold is 7-14 days. That means, on average, infants and toddlers can be sick for 4-6 months each year. Statistically, this means that 50% of children will be sick more than this. Parents, you’re not imagining things when you think your kids are sick all the time. Sometimes they are, and that’s not abnormal.”
So if it’s normal for kids to be almost continually sick this time of year, when should parents worry that their child’s immune system may not be working as well as it should?
There are two main types of immune deficiencies. The first type is secondary or acquired immunodeficiencies. These are the most common. This type of immune deficiency is caused when your child is fighting another illness like cancer, HIV or is taking certain medications that can suppress the immune system. We’re not going to talk about these today. The second type is primary immunodeficiencies (PID), which are far more rare and genetic (meaning we’re born with them). These are the disorders that parents say they’re most concerned about when they tell me their child is always sick.
PIDs, especially the more severe forms, are quite rare in the general population. There are roughly 180 distinct PIDs, however as category only about 0.0087% of the population has any one of those 180 PIDs. That’s about one out of 1,200 people, but this changes dramatically based upon the type of PID as some are much rarer than others.
Primary immune deficiencies arise when parts of the immune system are not being produced, or are not functioning appropriately. This leaves holes in the normal defense system, making the body more susceptible to infections. Depending upon where and to what degree the defect occurs, the impact can range from mild to very severe.
As I mentioned before, PIDs are genetic, but that doesn’t mean that they’re all inherited or passed from parent-to-child. Some may arise from spontaneous gene mutations with no family history at all. Some appear early in infancy with severe life-threatening infections, whereas others are very subtle and go undetected until adulthood.
So when should you worry that your child’s immune system is deficient? Unfortunately there’s no easy answer, but there are some indicators in the first years of life that your child needs to be evaluated by a pediatric allergist/immunologist:
- Positive Newborn Screening: As of this writing, 32 states screen for Severe Combined Immune Deficiency, which is an exceptionally rare condition that can cause death by one year of age from severe illness. If your baby’s newborn screening is positive for this, you need to see a pediatric immunologist immediately.
- Family History: If you or if certain blood relatives have been diagnosed with a PID or receive immunoglobulin replacement therapy.
- Failure to Thrive: If your baby fails to gain weight, meet their milestones, suffers from severe skin rashes, recurrent diarrhea, and frequent or invasive infections like sepsis or pneumonia.
- Opportunistic Infections: If your infant or child has suffered from recurrent opportunistic infections, such as fungal infections like thrush, that have affected more than just their tongue or mouth, this is cause for concern.
- Frequent Use of Antibiotics: If your infant or child has required multiple courses of antibiotics each year for confirmed infections such as pneumonia (diagnosed by chest x-ray), ear infections requiring placement of ear tubes, or sinus infections that will not resolve on their own.
- Confirmed Comorbidities: When two conditions tend to occur together we call these conditions “comorbid”. Some conditions, such as DiGeorge syndrome, are known to be comorbid with PIDs.
Most of these warning signs aren’t subtle, and statistically speaking PIDs are incredibly rare. As a board certified pediatric allergist/immunologist, I have received specialized training to identify children with possible PIDs, but sometimes a child with one of these conditions won’t have any of these warning signs. Sometimes the parents bring them in because their gut tells them that something isn’t quite right, and as the parents tell me more about their child’s issues my radar starts to go off. What are those signs?
- Infections that require treatment with intravenous antibiotics, especially more than once.
- Infections that occur in unusual sites, like internal organs, gums or skin abscesses (non-MRSA, or antibiotic resistant staph, which is a common infection).
- Infections with unusual organisms, which requires appropriate cultures from the site of infection.
- Infections of unusual frequency. While the average child has between 6-10 upper respiratory infections each year, if that number is closer to 20, or if it regularly takes more than three weeks to recover from each infection, I start to get concerned.
When I speak with concerned parents many of them understandably want to tell me everything, concerned that a small detail could be key in properly diagnosing their child. They’re often frustrated when I only ask about certain issues or don’t give some symptoms as much weight as the parents have. As an immunologist, I am extremely picky when taking a history. What I need to see are lab results and confirmed diagnoses.
I know that antibiotics are unfortunately often overprescribed for routine viral infections, so when a parent tells me that their child has been on antibiotics six times this year, I can’t give that information much weight unless it’s backed up with other historical details or test results confirming frequent bacterial infections. Many walk-in clinics or emergency rooms may diagnose a child with pneumonia just by listening to their lungs, but that doesn’t actually confirm pneumonia. What I need to see are the chest x-rays that are consistent with the diagnosis. I need to know that your doctor recorded a fever when they saw your child for an ear infection and that your child was in discomfort, not just that the eardrum was red (especially if they weren’t complaining about it beforehand). If your child has recurrent skin abscesses, I need to see the results from the cultured bacteria to determine if the bacteria are consistent with the type of bacteria we see when the immune system isn’t functioning.
I know this is frustrating for parents, especially if the necessary some of these steps haven’t been taken before they arrive at my office. Testing for PIDs can be invasive, uncomfortable and stressful for children, and the last thing I would want to do is to subject any child to those tests if it wasn’t necessary. So before I can tell if your child requires further testing, I need you to arm me with as much data as possible.
I’m rarely able to give parents a diagnosis or next steps the first time we meet. It takes time to carefully review all of the concerns and then thoughtful consideration about if and what testing should be performed. Sometimes we check labs just to help rule out a scary diagnosis and provide reassurance to parents. Sometimes we decide to perform watchful waiting, knowing that some kids just have bad luck and suffer from a few severe infections in a row. Again, while blood draws and other tests may be no big deal for most adults, for kids they can be terrifying and painful. As a father of two, the last thing I’d want is for my own children to go through that unless it was necessary.
When I tell concerned parents that their child’s medical history and symptoms likely aren’t indicative of a primary immune deficiency, what are some of the other reasons their child is so sick? Before we worry about PIDs we need to first consider the secondary causes of frequent infections. Are they in daycare or have siblings in school? If so, then they are exposed to tons of ‘normal’ infections. Exposure to tobacco smoke in the home or car, underlying chronic health conditions such as allergies, asthma, cystic fibrosis, congenital heart disease, kidney disease, etc. can all lead to increased infections. Additionally, the waiting rooms in hospitals and doctor’s offices are cesspools! People are usually there because they’re sick; every surface they touch is a reservoir of germs. Door handles, chair arm rests, magazine covers, the pen you use to check-in are all covered in germs. If your child is at the doctor’s office being treated for one infection then quickly develops another infection, it is likely due to exposure to all the germs in health care facilities. I’ve seen countless kids develop vomiting/diarrhea days after being treated by their doctor for a respiratory illness.
If you have concerns about your child’s health it’s always OK to call your child’s doctor to talk through your concerns and see if a referral to a pediatric allergist/immunologist is appropriate. Hopefully this post puts your mind at ease or at the very least arms you with more information.