Tonsils are functional immune organs, but they are not essential for long-term health. They serve as early surveillance stations for airborne and swallowed pathogens, sampling what enters your mouth and nose and helping coordinate an immune response. That role matters most during early childhood, when the immune system is still learning to recognize threats. Once the rest of the immune system matures, tonsils become less critical, which is why removing them rarely causes lasting immune problems for most people. The more interesting question is when they cross the line from helpful to harmful, and why the medical answer to that question has shifted dramatically over the past century.
What Tonsils Actually Do
Your palatine tonsils sit at the back of your throat, right where the air you breathe meets the food you swallow. That placement is not accidental. Tonsils act as immunological sentinels at this crossroads, bridging the body’s quick-response defenses with its longer-term adaptive immunity through specialized internal structures.1PubMed. Novel Findings on the Development and Immunological Functions of Palatine Tonsils They contain immune cells organized in ways that allow them to detect bacteria and viruses early, before those pathogens can reach deeper into the lungs or gut.
One of their most important jobs involves producing a type of antibody called secretory IgA. This antibody coats the surfaces of your airways, mouth, and eyes, acting like a sticky trap for germs. Tonsils generate the B cells that produce this antibody and then send those cells to mucosal surfaces throughout the upper body, including salivary glands and lacrimal (tear) glands.2International Journal of Pediatric Otorhinolaryngology. Immunology of tonsils and adenoids: everything the ENT surgeon needs to know Research has linked immune responses initiated in the tonsils and adenoids to the IgA found in saliva, confirming that these tissues actively contribute to the defense of the entire upper airway.3PubMed Central. Secretory immunity with special reference to the oral cavity
Tonsils are not unique to humans. A review of tonsil anatomy across domestic and laboratory animals found that various species carry some combination of up to six different types of tonsils. Sheep and goats have all six. Pigs lack palatine tonsils entirely. Rats and pigeons have no proper tonsils at all.4PubMed Central. The tonsils revisited: review of the anatomical localization and histological characteristics of the tonsils of domestic and laboratory animals The fact that some species get along fine without them tells us something about how essential they really are: useful, not irreplaceable.
How Tonsils Change with Age
Tonsils are largest relative to a child’s airway in early childhood. A longitudinal study tracking Japanese children from elementary school through young adulthood found that tonsil size decreased significantly between the early school years and adulthood, shrinking from an average cross-sectional area of about 161 mm² in younger children to roughly 111 mm² in young adults.5Scientific Reports. Patterns of adenoid and tonsil growth in Japanese children and adolescents: A longitudinal study This natural shrinkage is part of why many children “outgrow” their tonsil problems. The immune tissue slowly recedes as the broader immune system takes over its surveillance duties.
The trouble comes when tonsils are disproportionately large for the airway that surrounds them. In children without sleep or breathing issues, both tonsils and adenoids tend to follow a predictable shrinkage curve. But in children with snoring, tonsils remain persistently large regardless of age, and the airway behind the nose grows more slowly than it should.6The Journal of Pediatrics. Age-Dependent Changes in the Size of Adenotonsillar Tissue in Childhood: Implications for Sleep-Disordered Breathing For these kids, the standard “wait and they’ll shrink” advice does not always hold.
When Tonsils Cause Problems
The most familiar tonsil problem is tonsillitis, which can be caused by viruses or bacteria. A prospective study comparing the two found that viral infections accounted for roughly two-thirds of tonsillitis cases, with adenovirus being the most common culprit. Bacterial cases made up the remaining third, dominated by Group A Streptococcus.7Journal of American Medical Science and research. A Prospective Study Comparing Bacterial and Viral Tonsillitis, Diagnostic Pattern and Therapeutic Outcomes In strep cases, the bacteria colonize the tonsil surface within the first day of symptoms, establishing an infection that the tonsils were supposed to prevent.8PubMed Central. Initial events in the pathogenesis of acute tonsillitis caused by Streptococcus pyogenes In a sense, the organ designed to trap pathogens becomes the very site where they flourish.
Enlarged tonsils also play a major role in sleep-disordered breathing in children. Adenotonsillar hypertrophy is the leading cause of obstructive sleep apnea in the pediatric population.9PubMed. Obstructive sleep apnea syndrome due to adenotonsillar hypertrophy in infants Larger tonsils and adenoids are linked to more severe sleep apnea, and obesity compounds the problem. One study found that obesity roughly tripled the odds of obstructive sleep apnea in children, while enlarged tonsils tripled them as well, and enlarged adenoids nearly doubled them.10PLOS ONE. Associations between Adenotonsillar Hypertrophy, Age, and Obesity in Children with Obstructive Sleep Apnea When a child snores loudly, stops breathing during sleep, or is unusually tired during the day, oversized tonsils are often a primary suspect.
Tonsil Stones Are a Separate Nuisance
Tonsil stones, or tonsilloliths, are whitish-yellow lumps that form in the crevices of the tonsils. They are common, frequently harmless, and almost always the explanation for the complaint “my breath smells terrible even though I brush my teeth.” Research has shown that tonsil stones are not inert mineral deposits but living biofilms, structurally similar to dental plaque. They contain layered communities of bacteria, with oxygen-consuming species on the outside and acid-producing anaerobic bacteria buried deeper inside. When researchers measured the oxygen level at the center of a tonsillolith, it had dropped to about one-tenth of the surrounding fluid, and adding sugar caused the pH to plummet from neutral to acidic.11PubMed. Tonsillolith: not just a stone but a living biofilm This oxygen-depleted, acidic core fosters exactly the kind of bacteria that produce foul-smelling sulfur compounds.
A similar process occurs in adenoid tissue, where bacterial aggregates form in cryptic spaces with the same mix of inflammatory cells and complex microbial communities found in tonsil stones.12PubMed Central. Adenoid Stones – “Adenoliths” Tonsil stones alone are not a standard reason for tonsillectomy, but when they are large, recurrent, and causing persistent bad breath or discomfort, they can factor into the decision.
When Doctors Recommend Removal
Tonsillectomy guidelines have become considerably more conservative since the early twentieth century, when the procedure was recommended for everything from poor appetite to bed-wetting.13The Journal of Laryngology & Otology. The impact of new evidence on regional variation in paediatric tonsillectomy and adenoidectomy: a historical review Today, the clearest evidence-based criteria for recurrent infections are what are known as the Paradise criteria, named after the researcher who defined them in the 1980s. These criteria require that a child has had at least seven episodes of significant sore throat in one year, five per year for two years, or three per year for three years, with each episode documented by a doctor and accompanied by at least one objective sign such as fever above 38.3°C, swollen neck glands, tonsillar pus, or a positive strep test.14PubMed. Clinical practice guideline: tonsillectomy in children
A Cochrane review found that the benefits of tonsillectomy are greatest in children who meet these strict criteria. In the original research, meeting the bar required not just frequent infections but documented treatment and clinical records for each episode.15Cochrane Database of Systematic Reviews. Tonsillectomy versus non-surgical management for chronic/recurrent acute tonsillitis Evidence-based indications also include rare conditions like PFAPA syndrome (a periodic fever disorder in children) and suspected tonsillar tumors.16PubMed Central. Incidence of indications for tonsillectomy and frequency of evidence-based surgery: a 12-year retrospective cohort study of primary care electronic records For sleep-disordered breathing caused by enlarged tonsils, the threshold for surgery is generally lower, because the consequences of untreated pediatric sleep apnea on growth and development are well established.
For adults with recurrent tonsillitis, the picture is murkier. Many cases are self-limiting and resolve on their own over time. The three standard management approaches are watchful waiting, antibiotics for acute episodes, or tonsillectomy.17PubMed. Is tonsillectomy recommended in adults with recurrent tonsillitis? Surgery tends to be reserved for patients whose episodes are genuinely debilitating, frequent enough to interfere with work, or unresponsive to conservative management.
Partial Versus Total Removal
A growing trend in pediatric surgery is partial tonsillectomy, sometimes called tonsillotomy or intracapsular tonsillectomy. Instead of removing the entire tonsil, the surgeon shaves it down while leaving a thin rim of tissue and the outer capsule intact. This approach was developed primarily for children whose main problem is airway obstruction rather than recurrent infection.
The recovery advantages are substantial. A systematic review found that partial tonsillectomy reduced the odds of post-operative bleeding by about 79%, cut hospital readmissions by roughly 62%, and shortened the time it took children to return to normal eating by nearly three days compared to total removal.18International Journal of Pediatric Otorhinolaryngology. Tonsillectomy or tonsillotomy? A systematic review for paediatric sleep-disordered breathing A separate study comparing bleeding rates directly found that about 7% of total tonsillectomy patients experienced post-operative bleeding versus roughly 1% of partial tonsillectomy patients.19International Journal of Pediatric Otorhinolaryngology. Post-operative bleeding is less after partial intracapsular tonsillectomy than bipolar total procedure
The trade-off is that tonsil tissue can regrow. Because the remnant remains, some children eventually need a second procedure if infections become a problem later. For recurrent tonsillitis, total removal is still the standard recommendation precisely because leaving tissue behind defeats the purpose of eliminating the infection reservoir.
Recovery Is Harder for Adults
If you are an adult considering tonsillectomy, know that recovery is measurably rougher than it is for children. Adults report significantly higher pain scores after surgery.20International Congress Series. Postoperative pain after tonsillectomy—comparison of children and adults The complication rate is also markedly higher: one study of day-case tonsillectomies found a 30-day complication rate of about 8% in children versus 35% in adults, with bleeding being the main concern.21European Annals of Otorhinolaryngology, Head and Neck Diseases. Tonsillectomy in children and in adults: changes in practice following the opening of a day-surgery unit with dedicated operating room
Part of the reason involves how the surgical wound heals. After the tonsils are removed, a fibrin membrane forms over the raw tissue bed. That membrane typically covers the full surface by about day five and detaches around day seven, right when new blood vessel growth is at its peak. When the membrane separates, those fragile new vessels are briefly exposed, which is why the risk of bleeding spikes roughly a week after surgery.22PubMed Central. Post-tonsillectomy Hemorrhage: A Seven-year Retrospective Study Adults tend to form thicker scabs and have more vascular tissue, both of which contribute to the higher bleeding rates.
What Happens to Your Immune System After Removal
This is the question most people have, and the answer is genuinely mixed. A comprehensive review concluded that removing tonsils and adenoids does not appear to negatively affect cellular or humoral immunity in a lasting way. However, the same review noted that surgery may lead to a higher incidence of certain infectious diseases.23PubMed Central. Effects of tonsillectomy and adenoidectomy on the immune system That distinction matters: your immune system’s overall machinery keeps working, but you may lose some of the local frontline defense that was preventing upper respiratory infections.
One study found that children who had undergone tonsillectomy had lower blood levels of certain antibodies (IgM, IgA, and IgG) compared to children who kept their tonsils, though key immune cell counts were unaffected.24PubMed Central. Long-term impacts of tonsillectomy on children’s immune functions The most striking data comes from a large Danish population study that followed people for up to 30 years after childhood surgery. Tonsillectomy was associated with a nearly tripled relative risk of upper respiratory tract diseases, and adenoidectomy was linked to a roughly doubled risk of both upper respiratory diseases and chronic obstructive pulmonary disorder. When the researchers looked across 28 disease categories, the majority showed small but statistically significant risk increases after surgery.25JAMA Otolaryngology–Head & Neck Surgery. Association of Long-Term Risk of Respiratory, Allergic, and Infectious Diseases With Removal of Adenoids and Tonsils in Childhood
These numbers deserve context. A tripled relative risk sounds alarming, but relative risk can be misleading when the baseline rate is low. The study estimated that for every five tonsillectomies performed, roughly one additional case of upper respiratory disease would be associated with one of those patients, which suggests the absolute risk increase is not trivial but also not catastrophic. And the study could not fully control for the reason the surgery was performed in the first place: children who needed tonsillectomy already had more throat problems than average, which could inflate the post-surgery disease rates.
Growth Improvements in Children
One of the more dramatic benefits of tonsillectomy in children with obstructive sleep apnea is a measurable catch-up in growth. Children with enlarged tonsils that block their airway often experience a slowdown in weight gain and height. After surgery, growth accelerates even when calorie intake stays the same. One study found that children gained an average of nearly 3 cm in height and showed significant increases in weight-related measures within three months of surgery, with levels of a key growth factor (IGF-1) rising substantially.26PubMed Central. Modification of growth, immunologic and feeding parameters in children with OSAS after adenotonsillectomy
A population-based cohort study confirmed this pattern at a larger scale, finding that children who underwent tonsillectomy and adenoidectomy gained more weight and height than matched controls, with weight gain appearing quickly after surgery and height increases becoming apparent more than a year later.27Sleep Medicine. Changes in childhood growth after adenotonsillectomy: a population-based cohort study An earlier study found that three-quarters of children showed a jump to a higher weight percentile after surgery, with most showing changes of 15 percentile points or more.28PubMed. The effects of adenotonsillectomy on growth in young children The mechanism seems to be improved sleep quality and breathing, which normalize growth hormone release patterns during sleep, rather than any change in appetite.
A Sometimes-Overlooked Cause of Recurring Infections
If you or your child keeps getting tonsillitis despite doing everything right, there may be an underlying immune issue worth investigating. A study of adults with recurrent tonsillitis found that roughly a quarter had a selective humoral immunodeficiency, compared to only 8% of healthy controls. These patients had significantly lower levels of multiple antibody types and higher rates of both tonsillitis and sinus infections.29PubMed. Prevalence of humoral immunodeficiency in adult patients with recurrent tonsillitis The researchers suggested that immune function testing should be routine in adults with frequent throat infections, but it frequently is not.
The problem is compounded by the fact that when unusual bacteria show up in a throat culture, clinicians sometimes dismiss them as contamination rather than considering that the patient’s immune system may not be handling routine pathogens normally.30Kahramanmaraş Sütçü İmam Üniversitesi Tıp Fakültesi Dergisi. A Rare But Significant Cause of Recurrent Pseudomonas Tonsilitis: Common Variable Immunodeficiency If tonsillectomy is performed without identifying an underlying immunodeficiency, the infections may simply shift to other sites.
Tonsils and Cancer
Tonsillar carcinoma is uncommon, but it has one of the strongest known links to human papillomavirus (HPV) among non-genital cancers. A review of over 400 analyzed tonsillar carcinomas found HPV DNA in about half of them, with HPV-16 accounting for the vast majority of those cases.31PubMed Central. HPV infections and tonsillar carcinoma A separate study comparing cancerous and non-cancerous tonsil tissue found that high-risk HPV types were present in about 45% of tonsillar cancers but only 5% of non-malignant samples, with viral loads many orders of magnitude higher in the cancerous tissue.32PubMed. Human polyomavirus and human papillomavirus prevalence and viral load in non-malignant tonsillar tissue and tonsillar carcinoma
This is relevant to the “do we need tonsils” question in a roundabout way. The HPV vaccines now available cover the high-risk strains most associated with tonsillar cancer. For adults who still have their tonsils, being aware that persistent throat symptoms, unexplained swelling on one side, or ear pain should prompt a visit to a doctor is more practical than worrying about whether keeping your tonsils puts you at risk. Tonsillar cancer in adults is almost always caught because of asymmetric enlargement of one tonsil, which can prompt a biopsy.
Who Gets the Surgery and Who Doesn’t
Access to tonsillectomy is not equal. A systematic review looking at social determinants found that Black children in the United States underwent tonsillectomy at significantly lower rates than white children in every study that examined the question. Those differences held up even after controlling for age, sex, obesity, insurance status, and socioeconomic background, suggesting that the disparity reflects something beyond simple insurance access.33PubMed Central. The impact of social determinants of health on pediatric tonsillectomy Separately, population-based studies have found that children with public insurance were actually more likely to undergo tonsillectomy than those with private insurance, which complicates the intuition that cost is the primary barrier.
These patterns matter because sleep-disordered breathing in children, which tonsillectomy can resolve, has downstream effects on school performance, behavior, and long-term cardiovascular health. A child who needs the surgery but does not get it faces real consequences, and those consequences accumulate most in populations that already face other health disadvantages.