What Are the Early Signs of Autism in Toddlers? A Guide for Philadelphia Parents

If something about your child's development feels a little different, you're probably paying close attention. Maybe it's the way they communicate, how they respond to people around them, or how they handle changes in routine. Listen to that instinct. Knowing what early signs of autism spectrum disorder (ASD) in toddlers may look like can help you decide when to talk with your pediatrician and what steps to take next.

When do children start showing signs of autism?

Early signs of autism in children don't always follow the same pattern. For some children, differences show up in infancy. For others, they become more noticeable during the toddler years, as communication, social interaction, and play skills continue to develop. What matters most is recognizing patterns over time and trusting your instincts as a parent.

According to the Centers for Disease Control and Prevention (CDC), most children reach a set of skills by certain ages.¹ 

• By 18 months, children are typically looking to see if a caregiver is nearby, using a few words, following simple directions, and imitating familiar routines. 
• By age 2, most are using simple two-word phrases, pointing to objects in books, and starting to run and kick a ball. 
• By age 3, many are having back-and-forth conversations, asking "who," "what," "where," "when," and "why" questions, drawing circles, and calming down within about 10 minutes after separating from a caregiver.

When a child isn't consistently meeting milestones in communication, social connection, or behavior, it can be a reason to take a closer look. That's where understanding early signs becomes useful.

Autism infants signs & symptoms: What families may notice first

Early signs and symptoms of autism in infants can be subtle, and they're easy to miss in those first months when so much is changing so quickly. Autism spectrum disorder symptoms in infants often show up not in dramatic differences, but in subtler patterns: how a baby connects, responds, and shares moments with the people around them.

Signs and symptoms of autism in infants may include:

• Limited eye contact
• Fewer social smiles or less back-and-forth facial expression
• Less interest in sharing attention with a caregiver, such as looking between an object and a parent
• Differences in responding to voices or familiar people
• Fewer early gestures and delays in nonverbal communication as development continues

Learn more: Q&A with a Psychologist: Common Autism Questions Answered

Common signs of autism in toddlers

Signs of autism in toddlers tend to cluster around four main areas: communication, social interaction, and restrictive or repetitive behaviors. Seeing one sign in isolation doesn't tell the whole story. What often carries more weight is whether the same patterns show up consistently across different situations and routines.

Some of the most common signs of autism in children during the toddler years include:

• Differences in joint attention, such as not consistently looking back and forth between a parent and an object to share interest
• Fewer or different gestures, including reduced pointing, waving, reaching, or showing things to others
• Language delays or differences, such as delayed speech, less back-and-forth babbling, or repeating words and phrases (known as echolalia)
• Differences in play, including repetitive ways of interacting with toys or reduced pretend play
• Strong distress when routines change, or transitions happen
• Regression, when a child loses words, social skills, or other abilities they had previously developed

The fifth edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-5) also notes that difficulty understanding social cues or nonverbal communication, such as facial expressions and gestures, is among the recognized signs of autism in children. Intense focus on specific topics or objects, hypersensitivity or hyposensitivity to sensory input like loud noises or bright lights, and a preference for particular sensory experiences are also described as common patterns.

Learn more: Autism 101: What Families Need to Know Webinar

Signs of autism in toddlers age 1

Around the first year, early signs of autism in toddlers may be easier to spot in how a child connects socially and uses early communication. At this stage, differences are often more subtle, but they can still be meaningful when they show up repeatedly.

Signs of autism in toddlers age 1 may include:

• Limited or inconsistent eye contact
• Not consistently responding when their name is called
• Fewer gestures, such as pointing, reaching, or waving
• Less back-and-forth smiling, babbling, or interaction with caregivers
• Reduced interest in sharing attention, like following a parent's gaze or pointing something out

Development at this age varies a great deal, so what matters most is looking for repeated patterns over time rather than reacting to a single moment.

Learn more: Supporting Siblings After an Autism Diagnosis

Signs of autism in toddlers age 2

By age 2, signs of autism in toddlers often become easier to recognize. As communication and social interaction develop, differences can show up more clearly in everyday routines, play, and interactions with others.

Signs of autism in toddlers age 2 may include:

• Limited words or slower language growth than expected
• Reduced pretend play or less interest in interactive play with others
• Repetitive movements or consistent, unusual ways of interacting with toys
• Difficulty with transitions or strong distress when routines change
• Limited interest in peers or less back-and-forth play
• Strong reactions to certain sounds, textures, lights, or other sensory experiences

Some children may also experience regression between about 15 and 24 months and lose words they'd been using or become more socially withdrawn. This is often a sign that it’s time to take the next step.

Learn more: Sensory-Friendly Activities & Autism Resources in Philadelphia

Uncommon signs of autism in toddlers parents may notice

Some early signs of autism are widely recognized. Others are talked about less often, but they can be just as meaningful for families trying to understand what they're seeing. Uncommon signs of autism in toddlers may include:

• A very focused interest in specific objects or particular parts of objects
• Strong distress over small changes in the environment or daily routine
• Advanced skills in one area alongside delays in another
• Repetitive ways of moving, such as rocking, hand-flapping, or spinning
• Appearing highly independent in some moments while seeming less engaged with people in others
• Unusual sensitivity or under-sensitivity to sensory input, such as seeking out certain textures or sounds

These patterns don't automatically point to autism. But when they appear alongside differences in communication, social connection, or behavior, they're worth discussing with a pediatrician.

Learn more: Getting an Autism Diagnosis Ebook

What autism screening and evaluation may look like

Many parents notice early signs of autism in their toddlers because they're paying close attention. Talking with your child's pediatrician is a good first step. You can also complete an online autism screener, like the M-CHAT-R (for toddlers) or the CAST (for older children). Autism screeners help identify whether a child may be at risk for autism and if further evaluation would be helpful. 

If your child receives a high-risk screener score or if you have ongoing concerns, a professional evaluation can provide a fuller picture of your child’s development. 

Learn more: Post Autism Diagnosis Guide for Families

Why an autism diagnosis matters

Early autism diagnosis opens the door to early intervention, and early intervention has been shown to support better long-term outcomes for autistic children. Many families find that having a diagnosis brings clarity and opens doors to a support system they didn't have before.

An autism diagnosis is often required before a child can:

• Access evidence-based autism services like applied behavior analysis (ABA) therapy
• Receive insurance coverage for autism treatment
• Qualify for special education support and school accommodations

Learn more: Check if Action Behavior Centers accepts your insurance

How ABC supports families in Philadelphia

Action Behavior Centers supports autistic children ages 18 months to 8 years, with ABA therapy centers in Horsham, Newtown, and King of Prussia. For families who are still looking for answers, we also offer autism evaluation support, including Initial Diagnostic Evaluations (IDEs) with licensed psychologists available in-center or via telehealth. 

Our insurance specialists can help verify your coverage and walk you through paperwork and preauthorizations. If you're noticing early signs of autism in your toddler, trying to understand the autism evaluation process, or ready to schedule a tour, contact us today. Milestone moments start here.