Brain Fog and Cognitive Symptoms in Children With Lyme Disease

Updated January 2026

Many parents notice something is wrong long before they have a name for it. A child who once learned easily may begin to struggle to concentrate. Homework takes longer. Instructions need to be repeated. Teachers mention inattention or declining performance. At home, the child may seem mentally “elsewhere,” easily overwhelmed, or emotionally reactive.

In children with Lyme disease, these changes are often described as brain fog. While the term is informal, it captures a very real pattern of cognitive dysfunction that can interfere with learning, behavior, and daily functioning.

Importantly, these cognitive changes are usually functional. They do not mean a child is losing intelligence or experiencing permanent brain damage.

This article focuses on children. For a broader overview of brain fog and cognitive dysfunction in both adults and children with Lyme disease, see Brain Fog and Cognitive Dysfunction in Lyme Disease.

“For a broader clinical framework on how Lyme disease becomes chronic, see Preventing Chronic Lyme Disease.”

---

What brain fog looks like in children

Children rarely describe brain fog directly. Instead, it shows up in subtle and frustrating ways. A child may appear inattentive, forgetful, or slow to process information. They may struggle to keep up with classroom demands or lose track of multi-step instructions.

Tasks that once felt automatic can suddenly require enormous effort. Parents often hear concerns about attention or motivation, while the child insists they are trying their best. This disconnect can create tension at home and school, especially when standard testing does not reveal obvious abnormalities.

For a broader discussion of how Lyme disease affects cognition across all ages, see our overview of brain fog and cognitive dysfunction in Lyme disease.

---

Why brain fog is often missed or misunderstood

Brain fog in children is frequently mistaken for anxiety, attention-deficit disorders, or behavioral problems. Because routine imaging and laboratory studies are often normal, cognitive complaints may be minimized or attributed to stress or mood.

In Lyme disease, however, cognitive symptoms can occur even when standard tests are unrevealing. Subtle changes in brain function, inflammation, and signaling can impair processing speed, working memory, and mental endurance. These changes may not appear on routine studies, but they are still very real for the child experiencing them.

---

The neurologic basis of cognitive symptoms in pediatric Lyme disease

Lyme disease can affect the central nervous system in ways that disrupt how the brain processes information. Immune activation, neuroinflammation, and altered neurotransmitter function may interfere with attention, memory, and executive functioning.

In children, whose brains are still developing, these disruptions can have a disproportionate impact. The result is not a loss of intelligence. Rather, it is reduced cognitive efficiency, especially during periods of stress or fatigue.

---

Cognitive overload and emotional regulation

Cognitive strain and emotional regulation are closely linked. When a child is struggling to process information or sustain attention, the nervous system can become overwhelmed.

This overload often contributes to irritability, emotional outbursts, or withdrawal. In some children, it may appear as oppositional or defiant behavior. What looks like misbehavior may actually reflect a child who has reached their cognitive limit and cannot manage additional demands.

Cognitive overload can also contribute to emotional dysregulation and oppositional behavior in children with Lyme disease.

---

School performance and learning challenges

School environments place sustained demands on attention, processing speed, memory, and sensory tolerance. For a child experiencing brain fog, these demands can quickly become exhausting.

Teachers may notice declining grades, incomplete work, or difficulty following classroom routines. Parents may observe school avoidance, academic anxiety, or a sudden drop in confidence. These challenges do not reflect laziness or lack of effort. They reflect a nervous system struggling to meet expectations it previously handled with ease.

If school refusal is part of your child’s picture, see our related article on school refusal in children with Lyme disease.

---

Fluctuation and unpredictability of symptoms

One of the most confusing aspects of brain fog in children is its variability. A child may function well one day and struggle significantly the next.

This fluctuation can lead adults to assume inconsistency or lack of motivation. In reality, symptom variability is a hallmark of neurologic and immune dysregulation. Cognitive capacity may change depending on sleep quality, stress, physical exertion, or immune activity.

---

Overlap with immune-mediated neuropsychiatric syndromes

Some children with Lyme disease experience cognitive symptoms alongside abrupt behavioral or emotional changes. These presentations may overlap with immune-mediated neuropsychiatric syndromes such as PANS.

While diagnostic labels vary, the unifying theme is immune and nervous system dysregulation affecting cognition and behavior. Recognizing this overlap helps families and clinicians move away from rigid categories and toward a more integrated understanding of the child’s symptoms.

---

Why reassurance matters

Parents often worry that cognitive symptoms signal permanent damage or long-term decline. In most cases, this fear is unfounded.

Brain fog in children with Lyme disease is typically functional and potentially reversible. With appropriate recognition and support, many children experience gradual improvement as neurologic stability returns. Progress may be uneven, but improvement is common.

---

Supporting children with brain fog

Children benefit most when their symptoms are acknowledged and validated. Reducing unnecessary pressure, adjusting expectations, and providing appropriate academic accommodations can significantly reduce stress on the nervous system.

Understanding that cognitive symptoms are part of illness — not a failure of effort or character — helps preserve self-esteem and emotional well-being during recovery.

---

Relationship to persistent symptoms

In some children, cognitive symptoms persist even after initial treatment for Lyme disease. This does not necessarily indicate ongoing infection. Instead, it may reflect continued nervous system or immune dysregulation.

Recognizing persistent cognitive symptoms as part of a broader post-infectious pattern allows for more thoughtful evaluation and avoids dismissal or blame.

---

Key clinical takeaways

Brain fog in children with Lyme disease reflects neurologic and immune dysfunction rather than loss of intelligence or motivation. Cognitive symptoms may affect attention, memory, processing speed, and school performance, often fluctuating over time. These challenges frequently overlap with emotional and behavioral changes and benefit from a compassionate, systems-based approach.

---

Parents often have practical concerns about how brain fog affects daily life, learning, and recovery.

---

Frequently Asked Questions for Parents

Is brain fog in children with Lyme disease permanent?
In most cases, no. Brain fog in children with Lyme disease is typically functional rather than degenerative and often improves over time as neurologic stability returns.

Why does my child seem better some days and worse on others?
Fluctuation is common and reflects changes in sleep, stress, immune activity, and cognitive load. Variability does not mean a child is exaggerating or regressing.

Can brain fog affect behavior or emotions?
Yes. When cognitive demands exceed a child’s neurologic capacity, frustration, irritability, emotional outbursts, or withdrawal may occur.

Why are tests often normal if my child is struggling cognitively?
Standard imaging and laboratory tests may not detect subtle changes in brain function or inflammation. Normal results do not rule out real cognitive symptoms.

Will school demands make brain fog worse?
In some children, sustained cognitive demands can worsen symptoms. Understanding this helps families and schools adjust expectations and reduce stress during recovery.

---

Selected links

Pediatrics Skogman BH, Ernerudh J, Forsberg P, Bergström S. Long-term clinical outcome after Lyme neuroborreliosis in childhood. 2012;130(2):262–269. Pubmed

Journal of Neuropsychiatry and Clinical Neurosciences Tager FA, Fallon BA, Keilp J, et al. A controlled study of cognitive deficits in children with Lyme disease.  2001;13(4):500–507. Pubmed

Pediatrics Vázquez M, Sparrow SS, Shapiro ED. Long-term neuropsychologic and health outcomes of children with facial nerve palsy attributable to Lyme disease.  2003;112(2):e93–e97. Pubmed

Pediatrics Bloom BJ, Wyckoff PM, Meissner HC, Steere AC. Neurocognitive abnormalities in children after classic manifestations of Lyme disease.  1998;102(4):E52. Pubmed

Children with Lyme
Two children who contracted Babesia from their mothers

How Do I Parent or Work With Lyme Disease? When Survival Becomes the Job