Strep throat is a common bacterial infection caused by Streptococcus pyogenes (Group A Streptococcus or GAS), primarily affecting the throat and tonsils. This infection causes tonsillitis, characterized by inflammation, swelling, a severe sore throat, fever, and sometimes white patches of pus. Understanding the expected timeline for the reduction of tonsil swelling is a primary concern during treatment. This article details the reason for the swelling, the typical recovery trajectory after starting antibiotics, and when persistent swelling requires further medical evaluation.
The Mechanism of Tonsil Swelling
The tonsils are oval-shaped masses of lymphoid tissue located at the back of the throat, acting as a first line of defense against inhaled or ingested pathogens. When Group A Streptococcus bacteria invade, the tonsils mount a vigorous immune response. This involves the rapid accumulation of immune cells, fluid, and inflammatory mediators in the tonsillar tissue.
The influx of these components causes the visible enlargement and redness, medically termed edema and erythema, which characterize tonsillitis. Swollen lymph nodes in the neck, which are connected to the tonsils, are also a common result of this localized immune response.
Expected Recovery Timeline
Noticeable relief from Strep throat symptoms occurs rapidly after beginning the prescribed course of antibiotics. Symptoms such as fever, body aches, and sore throat intensity often lessen significantly within 24 to 48 hours of the first dose. This quick improvement indicates the medication is effectively killing the Streptococcus bacteria, but the physical swelling has not yet fully resolved.
The reduction of tonsil swelling typically lags behind the symptomatic improvement. While the fever and pain may be gone, the noticeable enlargement of the tonsils and associated lymph nodes usually takes longer to subside. Initial, slight reduction in size often begins within three to five days of starting treatment.
Complete resolution of tonsil swelling can take a full seven to ten days, and occasionally longer, after treatment is initiated. The neck lymph nodes may remain slightly enlarged or tender for several weeks, or even months, after the infection is cleared. It is important to complete the full 10-day antibiotic course, even if swelling reduces sooner, to ensure all bacteria are eradicated and prevent complications like rheumatic fever.
When Swelling Persists
If tonsil swelling fails to improve after 48 hours of antibiotic therapy, or if it worsens, medical re-evaluation is necessary. This lack of response could indicate that the bacteria are resistant to the antibiotic used, or that the initial diagnosis was incorrect, meaning the infection is caused by something other than Streptococcus.
Prolonged or worsening unilateral swelling, where one tonsil is significantly larger than the other, may signal the development of a peritonsillar abscess. This is a serious complication where a collection of pus forms behind the tonsil. Symptoms suggesting an abscess include severe, localized throat pain, a muffled or “hot potato” voice, difficulty swallowing, and an inability to fully open the mouth, known as trismus.
Tonsils may also remain swollen if the illness was a viral infection, such as infectious mononucleosis (mono), caused by the Epstein-Barr virus. Viral tonsillitis does not respond to antibiotics and can cause severe tonsil swelling that may last for weeks. Any persistent difficulty with breathing, swallowing, or opening the mouth requires immediate attention, as these are signs of a medical emergency.