White spots on the back of the throat typically signify inflammation of the tonsils, known as tonsillitis. These white or pale yellow spots are often composed of pus (a collection of dead white blood cells), cellular debris, or mucus accumulated in the throat tissue. While they can appear alarming, these spots are a generalized symptom with a wide range of underlying causes that vary in severity. Identifying the type of infection—whether bacterial, viral, or fungal—is necessary for appropriate management.
Strep Throat and Other Bacterial Infections
The most frequent and medically significant bacterial cause of white patches in the throat is Streptococcus pyogenes, responsible for Strep throat. In this infection, the white spots appear as patchy or streaky exudates of pus directly on the tonsils and the back of the throat. Strep throat commonly features a sudden onset of a sore throat, painful swallowing, and a fever.
Unlike many other throat infections, Strep throat often lacks cold-like symptoms such as a cough or runny nose, helping physicians distinguish it from viral causes. Since this infection is bacterial, it requires antibiotics to prevent serious complications. Untreated Strep can lead to conditions like rheumatic fever (which damages heart valves) or post-streptococcal glomerulonephritis (which affects the kidneys). Other less common bacteria can also cause tonsillitis with white spots, but Group A Streptococcus remains the focus due to its potential for systemic complications.
Viral Causes Including Mononucleosis
Viruses are the most frequent cause of sore throats, and they can sometimes cause white spots or a white coating on the tonsils. These cases, often called viral pharyngitis, are usually part of a common cold and are accompanied by congestion, a cough, and other upper respiratory symptoms. Since antibiotics are ineffective against viruses, treatment involves supportive care, such as rest and pain relief, until the immune system clears the infection.
A notable viral cause is Infectious Mononucleosis (Mono), most frequently caused by the Epstein-Barr Virus (EBV). Mono can produce extensive white patches or exudates on the tonsils that look similar to Strep throat. Distinguishing features of Mono include profound fatigue, a prolonged recovery time (lasting several weeks), and significantly swollen lymph nodes, particularly in the neck. A severe sore throat with exudate that fails to respond to initial Strep treatment often prompts testing for Mono.
Fungal Infections and Tonsil Stones
Fungal infections, specifically oral thrush, can lead to white spots in the throat, especially in individuals with certain risk factors. Oral thrush is an overgrowth of the Candida albicans yeast, a fungus naturally present in the mouth. The white patches associated with thrush are typically creamy white and cottage cheese-like; they can often be scraped away, sometimes leaving a mildly bleeding, reddened area underneath.
This fungal overgrowth is common following a course of antibiotics (which disrupt normal mouth bacteria) or in people with weakened immune systems or diabetes. Separately, tonsil stones (tonsilloliths) are non-infectious white or yellowish formations that develop in the small crevices of the tonsils. These stones are hardened clusters of calcified materials, including food debris, minerals, and bacteria, trapped in the tonsil crypts. Tonsil stones are localized debris, not a widespread infection, often causing chronic bad breath or a feeling of something stuck in the throat. Simple measures like gargling with warm salt water can sometimes dislodge these formations.
Knowing When to See a Doctor
While many causes of white spots are self-limiting or easily treated, certain symptoms signal that medical consultation is necessary. If the white spots are accompanied by an extremely high fever, or if the sore throat and fever persist for more than a few days, a doctor should be consulted. Seeking professional care is important to test for Strep throat, as antibiotic treatment is needed to prevent potential long-term health issues.
Immediate medical attention is required if a person experiences signs of potential complications, such as difficulty breathing or severe pain that makes swallowing saliva nearly impossible. The inability to open the mouth fully or a muffled voice can signal a peritonsillar abscess—a collection of pus behind the tonsil that needs urgent drainage. A doctor will typically perform a physical examination and may use a rapid Strep test or a throat culture to identify Streptococcus bacteria. If Mononucleosis is suspected, a blood test may be ordered to confirm the diagnosis.