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A board certified allergist-clinical immunologist has the credentials to evaluate children who have an immune system that is "over-active" as in allergy and "under-active" or deficient. Clinical Immunology is involved in evaluating and treated children who have defects in their immune system. The defect leaves the child unprotected and may cause problems with recurrent infections. If your child is suffering from recurrent infections, an immune evaluation may be needed.
Immune deficiency conditions are rare and are not the only reason why a child has had more than their fair share of infections. There are four general reasons why children have recurrent infections. Those reasons are:
- Exposure to other children-epidemiology
- Structural or anatomic reasons- how the child was made
- Problems with the immune system:
- An over active immune system- classic allergy
- An under active immune system- immune deficiency
- "Other"- recurrent infections that are never totally cured
The number one reason why children may have recurrent infections- Epidemiology
This is the most common reason for recurrent infections. A number of years ago, in another Midwest city- Cleveland, Ohio, a very extensive study was performed that helped our understanding of recurrent respiratory tract infections. The authors (Dingle, Badger, and Jordan, 1964) discovered that the factors associated with recurrent infections were the age of the patient, the size of the family, the season of the year, and school exposure. This study would be considered "hallmark"- it has provided clinicians with valuable information to help focus immune evaluations and to reassure parents about their children.
First, lets look at how the age of the child relates to the number of respiratory tract infections per year.
|
Age |
Number of illnesses/year |
Range (min to max) |
|
<1 |
6.7 |
0-15 |
|
1 |
8.3 |
1-17 |
|
2 |
8.1 |
0-15 |
|
3 |
7.8 |
1-15 |
|
4 |
7.6 |
2-15 |
|
5 |
7.4 |
0-18 |
|
6 |
6.2 |
0-13 |
|
7 |
6.1 |
0-18 |
|
8 |
6.0 |
0-16 |
|
9 |
5.3 |
0-13 |
|
10 |
5.7 |
0-15 |
|
11 |
5.1 |
0-14 |
|
12 |
5.0 |
0-12 |
|
13 |
4.6 |
1-11 |
|
14 |
4.7 |
1-15 |
|
16 |
4.8 |
2-8 |
|
>16 |
4.6 |
2-11 |
I was most impressed with the wide range. A one- year old child may have on the average just over 8 colds/year, however she/he may have friends who are having 1 per year and another that has had 17 in a year! To look at this in another context- 17 colds per year with each lasting 10 days to 2 weeks would lead to as much as 34 weeks of respiratory tract symptoms in a child who has no immune problem or allergy problem. These numbers are impressive and in turn frustrating for a concerned parent.
Lets look at family size. When the study was conducted in the late 1950's to early 1960's, families tended to be somewhat larger than they are now. Since other people are usually the vector or source of infection, the more in the family the higher the numbers of infections that can be seen. Throughout this study, none of the children had allergy or a documented immune deficiency. This information describes what happens in a normal population (ok, it is Cleveland- I can jest about it, it is my home town).
| Family Size |
Illnesses per person per year
(respiratory) |
| 3 |
4.5 |
| 4 |
5.2 |
| 5 |
5.5 |
| 6 |
6.3 |
| 7 |
6.7 |
| 8 |
5.6 |
The time of the year and the occurrence of respiratory disease is as what we may guess. The peak times of the year for respiratory tract illness in this study was between September and March. We would expect more illness during this time of the year. When illness is an issue repeatedly during the summer months or there is absolutely no change in frequency at anytime of the year, an immune problem is worth considering.
The last contribution of this study was school exposure. These investigators found that once a child was in school, the incidence of respiratory tract infections increased. There was also an increase risk to the younger siblings when the older child was in school. Day care was not as common then as it is now. The Dingle study did look at children between the ages of 3-5 who were in a school setting. This increased the risk of respiratory tract infection.
Over the years there have been many studies looking at the incidence of infection in children who attend day care. A child in day care will increase the risk of upper respiratory tract infections anywhere from 2-8 times. When the child is in a one on one situation, just the child and the attending adult, they do better.
The most important consideration as to why a child is having recurrent infections is exposure to others.
Anatomic or structural reasons for recurrent infections
This is the second most common reason for recurrent illness. There can be a large number of these situations. They involve a number of organ systems of the body, and include problems with:
- Circulation- sickle cell disease, diabetes, kidney ailments, heart disease
- Obstruction- Eustachian tube (ear), cystic fibrosis, narrowing- stenosis
- Foreign bodies- shunts, catheters, valves, aspirated foreign bodies
- Broken barriers- eczema, burns, midline sinus tracts
- Irritants- not truly structural but a noted cause for recurrent respiratory illness is
- Cigarette-smoke exposure. Studies have shown as much as a 8-fold increase in respiratory tract illness when parents smoke.
- Other- abnormal cilia, the respiratory tract are lined with cells that make mucus and with cells that propel this mucus- our ciliated epithelium.
There are conditions that may lead to the destruction of these cells. Children may also be born with abnormal cilia.
The Immune System
This is the third most common reason for recurrent infections. There are two major areas to inquire about: 1. Is this allergy part of the picture? Or 2. Is there a deficiency of the immune system?
There are allergic conditions that may predispose to infection. Those illnesses may include allergic rhinitis, atopic dermatitis, and asthma.
Allergic rhinitis may be associated with as many as one-third of cases of serous Otitis media (chronic fluid in the ears). Infectious complications of allergic rhinitis may also include chronic sinusitis.
Those with atopic dermatitis who are constantly scratching and breaking down the skin barrier may suffer from recurrent skin infections.
Recurrent pneumonia, a concerning lower respiratory tract infections may very well be asthma.
The immune system is divided into four areas. Each area has its own type of infection. The type of infection, where it is happening and the nature of the organisms that are causing the infections help lead to where the defect is.
The four areas are:
- T-cells
- B-cells
- Polymorphonuclear cells
- Complement
Immune deficiency can be primary or secondary. The primary immune deficiencies are well described. There are a number of secondary immune deficiencies that are the consequence of other conditions. The immune system needs time to mature (recurrent infections are common in children). The immune system needs nourishment (nutrition is essential). The immune system needs to help from other body systems. What follows is a list of conditions that have been associated with recurrent infections.
Secondary Immune Deficiency:
- Premature infants
- Hereditary or rare metabolic conditions
Due to immunosuppressive agents- drugs, irradiation, oral steroids
- Infectious diseases
- Cancer and blood disorders
Due to surgery or trauma
- Malnutrition
The primary immune deficiencies are rare conditions. The most common is selective IgA deficiency, which may be seen in one in five hundred. Beyond this, the incidence of immune deficiency is 1 per one thousand in some conditions and 1 in 1 million in others.
Primary Immune Deficiency
T-Cell defects- The T-cells are the most import immune functioning cells. When these do not work, the most severe forms of immune deficiency will occur. The illnesses strike early in life. The infants have recurrent infections with unusual organisms. These infants fail to thrive. There may be a family history of these illnesses.
B-cell defects- The B-cell is responsible for antibody protection. Defects of this system are the most common. The hallmark is infection with specific organisms- encapsulated organisms that may cause high fever and invasive disease.
Polymorphonuclear cell defects are uncommon. Children with defects of these cells may have recurrent skin infections with staphylococcus or recurrent fungal infections.
Complement defects- are the rare. There can be recurrent infections with a very specific organism. There are abnormalities of this system that are associated with systemic lupus erythematosus.
Knowing what type of organism that is responsible for the infection helps define the possible defect in the immune system.
The Diagnosis of Immune Deficiency Conditions
The history should lead to what studies need to be done. There are also a number of issues that are specific to the children.
White blood cell numbers are different depending on the age of the child.
Serum immunoglobulin levels are also age specific and should not be compared to adult levels.
Antibody levels may vary according to age and immunization status.
A number of laboratory tests of immune function are sensitive to the effects of medications. Oral steroids may have an impact on the results.
The most important function of an immunoglobulin is what it does. This refers to antibody formation and function. When a low level of an immunoglobulin is found it is essential to determine whether or not there is a problem with antibody formation.
Be wary of IgG subclasses. A position paper from the American Academy of Allergy, Asthma and Immunology (AAAAI) has stated that the measurement of IgG subclasses should not be used as a screening test. It may not yield any more useful information than a determination of total IgG. Lets look at this from another perspective- in a child in which an immune deficiency is suspected, abnormal IgG subclasses would necessitate the need to do antibody studies and if the IgG subclass levels are normal, those antibody studies still need to be performed. The subclass does not help at all in the decision making process. Look to antibody response to define the defect.
Be wary of where the laboratory evaluation is being performed. Many local facilities do not offer the special tests that are needed for the diagnosis. Those physicians who evaluate these conditions know where to get the best and most reliable test results. They know where good work can be found. An obvious suggestion is for these evaluations to be done at a tertiary care center.
Once the diagnosis is made, treatment can be directed for support and towards the specific defect.
Clinical features of Immune Deficiency (some of the things that are seen along with the recurrent infections that may help define the condition):
Features that may be seen from birth to the 6th month of life:
- Low calcium
- Heart disease
- Peculiar look- facial features may be a clue
- Delayed separation of the umbilical cord
- Very high white blood cell counts or very low counts
- Diarrhea
- Pneumonia
- Thrush- recurrent and resistant to treatment
- Failure to thrive
- Swollen lymph nodes
- Severe skin conditions
- Bloody stool
- Draining ears
- Mouth ulcers
Infections - Key Features that may be seen 6th month to 5th year of life (in addition to infections):
- Severe infectious mononucleosis
- Paralytic disease after oral polio
- Recurrent infections with Staphylococcus
- Thrush
- Problems with the finger/toe nails
- Endocrine problems and infections
- Short stature, fine hair,
- Severe varicella (chicken pox)
- Swollen, large lymph nodes
- Recurrent pneumonia
- Bone infections
Features in Older Children (along with infections):
- Certain skin conditions
- Sino-pulmonary infections
- Neurologic deterioration
- Spider-like blood vessel patterns on the skin
- Recurrent infections with neisserial organisms
- Malabsorption syndromes
- Enlarged spleen
- Autoimmune illnesses
- Candida infections
Clinical Immunology Appointments
The referral should come from your primary care physician. We like to review all the records prior to the visit. Frequently, blood tests are needed to help with the evaluation. Our clinic utilizes the laboratories at Indiana University/Clarian. There are a few very special studies that I send out to laboratories that have provided quality work over the years.
All appointments for immune evaluations should be performed at the Riley Outpatient Center (ROC).
[Keywords: recurrent Infections, over active immune system, classic allergy, under active immune system, immune deficiency, Epidemiology, school exposure, upper respiratory tract infections, T-cells, B-cells, polymorphonuclear cells, complement, low calcium, heart disease, peculiar look- facial features, delayed separation of the umbilical cord, very high white blood cell counts, very low white blood cell counts, diarrhea, pneumonia, thrush, failure to thrive, swollen lymph nodes, severe skin conditions, bloody stool, draining ears, mouth ulcers, severe infectious mononucleosis, paralytic disease, oral polio, staphylococcus, finger/toe nails, endocrine problems, short stature, fine hair, severe varicella, chicken pox, swollen, large lymph nodes, recurrent pneumonia, bone infections, sino-pulmonary infections, neurologic deterioration, spider-like blood vessel patterns, neisserial organisms, malabsorption syndromes, enlarged spleen, autoimmune illnesses, candida infections.]
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