Signs and Causes of a Weakened Immune System

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Signs and Causes of a Weakened Immune System

If you’re always the first one to come down with a seasonal cold, and if it lingers long after everyone else is feeling better, you may wonder if you have a weak immune system. The answer is complicated, since sometimes when people talk about a compromised immune system, they mean they commonly catch illnesses that are going around. But in other cases, low immune system function is the result of immune system diseases, such as diabetes and lupus.

So how can you tell whether what you’re dealing with is just a lackluster immune response or if you have a more serious issue? Let’s start by examining how the immune system functions and identifying the common signs of a compromised immune system.

Woman sneezing

If you often suffer from the common cold or other types of infections, you may have a weakened immune response.

How the immune system works

The immune system is not one localized system. Instead, the immune system is made up of cells, tissues, and organs throughout the body that work together to protect you from potentially harmful invaders. Parts of the body involved in the immune system include:

  • Blood stream
  • Bone marrow
  • Lymphatic system
  • Mucosal tissue
  • Skin
  • Spleen
  • Thymus (11)

The immune system’s job is to protect us from infections by warding off harmful microbes like bacteria and viruses. It can also recognize and respond to unhealthy or abnormal cells, such as those that have been affected by infection or cancer. (11)

An immune system that’s working properly identifies and responds to the signals sent by unhealthy cells or microbes, and it activates its defenses to rid the body of them. Ideally, the immune system’s complex network of cells recognize threats, work to communicate with other cells, and perform a diverse range of functions to eliminate the threat. If you have a compromised immune system, however, your body may not be able to adequately defend itself and prevent infection. (11)

What causes a weak immune system?

Weak immune system causes are varied. Immunodeficiency, the term used to describe the state in which the body’s immune response is compromised or absent, can either be primary, meaning it occurs without something else triggering it, or secondary, meaning it’s the result of another condition or exposure.

Primary immunodeficiency

While there are more than 200 primary immunodeficiency disorders, some common examples include:

  • Severe combined immunodeficiency (SCID): Colloquially known as “bubble boy syndrome,” SCID is a group of rare disorders that affect a child’s immune system cells. This condition makes children more susceptible to serious and even life-threatening infections.
  • Common variable immunodeficiency (CVID): With CVID, genetic deficiencies prevent the immune system from producing enough antibodies, making those affected more likely to develop respiratory bacterial and viral infections.
  • CARD9 deficiency: This genetic disorder increases an individual’s susceptibility to Candida infections, a yeast fungus. (13)

Secondary immunodeficiency

Secondary immunodeficiency can be caused by another condition or certain medical treatments. For example, some cancer therapies suppress the immune system as a way to fight the cancer, but the consequence is that the immune system is less able to ward off other illnesses. Some other causes of secondary immunodeficiency include:

  • Human immunodeficiency virus (HIV): This virus suppresses the immune system. If not treated with antiretroviral drugs, HIV can lead to acquired immunodeficiency syndrome (AIDS)—a condition in which the body’s immune system is so badly damaged that it can’t protect the body from infection.
  • Malnutrition: Lack of protein, insufficient caloric intake, and micronutrient deficiencies all contribute to malnutrition, the most common cause of immunodeficiency worldwide. (3)
  • Metabolic diseases: The immune system and the metabolic system are intricately linked, and problems with one can impact the other. (10) Type 2 diabetes and other metabolic conditions impact the immune response by changing how cells respond to threats. That makes it harder for the body to fight off pathogens, which explains why people with metabolic conditions like diabetes are more susceptible to infections. (1)(6)

With some secondary immunodeficiencies, the immune system may return to its normal function if the underlying cause is addressed. For instance, when immunosuppressant therapy is discontinued, the immune system may regain its strength. In some cases, however, the immunodeficiency persists even after the condition resolves or the treatment ends. (3)

Signs of a weak immune system

If you have a compromised immune system, you may experience some of these signs and symptoms.

You often suffer from the common cold, and you can’t seem to kick it.

It’s normal for adults to get two or three colds a year, lasting approximately a week to ten days. (4) If you’re getting sick more often than that, or if illnesses persist for a long time, your immune system may be struggling.

You have frequent infections of other kinds, too.

If you have other infections like ear or sinus infections more frequently than normal, or if mild illnesses develop into more severe issues, you may have a weakened immune system. Some signs that your immune function is compromised include needing antibiotics more than twice a year (or more than four times a year for kids), having more than four ear infections a year after age four, or having more than three episodes of sinusitis in a year. (12)

You’re having skin or hair issues.

One of the ways immunodeficiency diseases can present themselves is with skin conditions and hair loss. If you have lesions, rashes, or even problems with your nails, a compromised immune system may be the culprit. (5)

Man sleeping in bed

Getting adequate sleep can help reduce your risk of infection and better recover from illness.

How to stay healthy with a compromised immune system

If for any of the reasons outlined above you suspect you have a low immune system, you can help protect yourself by taking the following precautions.

Practice good hygiene.

Wash your hands often and do a thorough job—wash for at least 20 seconds with soap and warm water, making sure to clean on the top and bottom of your hands, between fingers, and under your fingernails. When you don’t have access to soap and water, use sanitizer that’s at least 60% alcohol. (14)

Avoid touching your face or eyes.

Viruses and bacteria can enter the body through the nose, eyes, and mouth. Reduce your risk of exposure by keeping your hands away from your face. (14)

Keep your distance.

One surefire way to pick up a cold or other contagious illness is by interacting with people who are contagious. Remember that certain illnesses can even be contracted from people who aren’t showing symptoms. (7)

Get enough rest.

Sleep is essential for a happy immune system. Adequate sleep is linked to a lower risk of getting infections, and it can also help you recover better if you do develop an infection. (2)

Manage your stress.

Stress activates the immune system’s fight-or-flight response. It’s a way of readying your body to fight injury or infection that might occur when the body encounters a stressor. When stress is chronic instead of acute, your immune system remains activated. This can reduce your immune system’s ability to ward off harmful invaders. (9)

Maintain a healthy weight.

Obesity disrupts the body’s immune defense in a number of ways, including by impairing the function of immune cells and decreasing the amount of disease-fighting substances they produce. (8) All of this makes it harder to fight infection. Maintaining a healthy weight through healthy diet and exercise can help keep your immune system strong.

The bottom line

A healthy, robust immune system is the foundation of good health. If you are experiencing any of the weak immune system symptoms outlined here, consult your integrative healthcare practitioner.

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  1. Berbudi, A., Rahmadika, N., Tjahjadi, A. I., & Ruslami, R. (2020). Type 2 diabetes and its impact on the immune system. Current Diabetes Reviews, 16(5), 442–449.
  2. Besedovsky, L., Lange, T., & Haack, M. (2019). The sleep-immune crosstalk in health and disease. Physiological Reviews, 99(3), 1325–1380.
  3. Chinen, J., & Shearer, W. T. (2010). Secondary immunodeficiencies, including HIV infection. Journal of Allergy and Clinical Immunology, 125(2), S195–S203.
  4. Common colds. (2020, October 7). Centers for Disease Control and Prevention.
  5. de Wit, J., Brada, R. J. K., van Veldhuizen, J., Dalm, V. A. S. H., & Pasmans, S. G. M. A. (2018). Skin disorders are prominent features in primary immunodeficiency diseases: A systematic overview of current data. Allergy, 74(3), 464–482.
  6. Geerlings, S. E., & Hoepelman, A. I. M. (1999). Immune dysfunction in patients with diabetes mellitus (DM). FEMS Immunology & Medical Microbiology, 26(3–4), 259–265.
  7. How flu spreads. (2018, August 27). Centers for Disease Control and Prevention.
  8. Karlsson, E. A., & Beck, M. A. (2010). The burden of obesity on infectious disease. Experimental Biology and Medicine, 235(12), 1412–1424.
  9. Morey, J. N., Boggero, I. A., Scott, A. B., & Segerstrom, S. C. (2015). Current directions in stress and human immune function. Current Opinion in Psychology, 5, 13–17.
  10. Odegaard, J. I., & Chawla, A. (2013). The immune system as a sensor of the metabolic state. Immunity, 38(4), 644–654.
  11. Overview of the immune system. (2013, December 30). NIH: National Institute of Allergy and Infectious Diseases.
  12. Recurrent infections may signal immunodeficiencies | AAAAI. (n.d.). The American Academy of Allergy, Asthma & Immunology. Retrieved January 5, 2021, from
  13. Types of primary immune deficiency diseases. (2019, September 13). NIH: National Institute of Allergy and Infectious Diseases.
  14. When and how to wash your hands. (n.d.). Handwashing | CDC. Retrieved January 5, 2021, from


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