Our Services

In the office, Dr. Chung, MD, FAAP, and her staff provide comprehensive preventive care and sick care from newborns to young adulthood. The staff boasts a diverse array of experience and expertise to deliver effective treatment plans to address any health concerns.

Well-Child Exam

Routine well child exams present an opportunity to update immunizations, refill prescription medication, and address unusual symptoms or other health concerns. At Happy Bun Pediatrician, expert pediatrician Y.C. Jennie Chung, MD, FAAP, offers well child exams to young people of all ages, from infants to teens. To make an appointment for your child at the practice in McKinney, Texas, call the office or click the online booking tool today.

A well child exam is a critical component of preventive care. It’s a brief appointment that assesses your child’s health and well-being through various measures, including laboratory tests and screenings.

Most children undergo their first well child visit three to five days after being born. To ensure your child remains healthy, Dr. Chung recommends making an appointment at least once a year until they’re 18. 

A well child exam involves several parts, including:

Physical exam

Dr. Chung begins a well child exam by conducting a physical. She assesses your child’s eyes, ears, nose, and throat, gently palpates their organs, observes their gait and posture, and tests their reflexes. Afterward, she examines their skin for any unusual marks or growths.

Laboratory testing

Dr. Chung orders laboratory testing like blood work or urinalysis. These measures allow her to detect potentially serious health problems invisible to the naked eye like vitamin deficiencies, hormonal imbalances, or high cholesterol. 


Dr. Chung might recommend one (or several) vaccines, depending on your child’s age and medical history. Most immunizations only require one shot but some require two. 

Medication refills 

If your child takes medication for an underlying health problem, Dr. Chung can update the prescription. She also asks if they experience any side effects and if the medicine works as it should.

Nutritional and exercise guidance

Children’s bodies develop rapidly, so it’s important they eat a healthy, balanced diet that provides them with proper nutrition. If your child plays sports or participates in other physical activities, she can also make recommendations for warming up, cooling down, and preventing injuries.

Questions and answers

At the end of a well child exam, Dr. Chung sets aside time to answer any of you or your child’s questions. She recommends bringing a list of anything you’d like to discuss so you don’t forget anything. 

To ensure your son or daughter gets the most of their well child exam, Dr. Chung recommends bringing the following items:

  • A list of the medications or supplements your child currently takes
  • A list of any symptoms or pain your child is experiencing
  • Results from any recent or relevant tests
  • Your child’s medical and surgical history
Close-up of little child sitting on mother's knees while doctor examining him with stethoscope at hospital
Mother and her newborn baby on white plaid, closeup 2

Newborn Care

If you’ve recently had a baby, newborn care provides a way to assess their health and well-being, feeding habits, and development. At Happy Bun Pediatrics, expert pediatrician Y.C. Jennie Chung, MD, FAAP, provides newborn care on-site and through at-home visits. To make an appointment for your newborn at the practice in McKinney, Texas, call the office or click the online booking tool today.

The term newborn care refers to a series of preventive and general health services provided to infants. It involves screening tests, vaccines, and recommendations for new parents, as well as an opportunity to ask questions or discuss potential concerns. 

At Happy Bun Pediatrician, newborn care involves several steps:

Weighing and measuring the baby

At the beginning of a newborn care appointment, Dr. Chung measures your baby’s weight, length, and head circumference. Then, she compares the measurements with a growth chart to ensure your little one achieves specific milestones.

Review of eating, sleeping, and bathroom habits

Next, Dr. Chung asks you about your infant’s daily activities, including if they have a good appetite, how well they sleep, and the number of diapers they’re using each day. During this portion of the exam, feel free to ask questions or bring up concerns.

Physical exam

After gathering that information, Dr. Chung conducts a physical exam. She looks at their eyes, ears, nose, and throat; gently palpates their organs; listens to their heart and respiratory rate with a stethoscope; and inspects the umbilical cord.

Screening tests

Following the physical exam, Dr. Chung conducts a hearing test. If the provider who delivered your baby made any notes, she might also conduct additional screenings.


After completing the screening tests, your baby receives a series of vaccines. Vaccines train your baby’s immune system to identify potentially harmful invaders like viruses and bacteria. Some common vaccines that newborns receive include:

  • Hepatitis B
  • Diphtheria, Tetanus, and Pertussis (DTaP)
  • Polio
  • Pneumococcal disease
  • Rotavirus vaccine

The vaccines your child receives depends on their unique needs and medical history.

Safety tips

If you’ve never had a baby before, it’s normal to feel anxious and uncertain. Dr. Chung spends the last half of the appointment making safety recommendations, including information about how to install a car seat, how to swaddle your newborn, and how to respond if your baby becomes fussy or sick. 

Yes. To ensure your baby remains healthy, Dr. Chung recommends a check-up at one, two, four, six, nine, and 12 months. At each appointment, she administers additional vaccines, conducts age-based screenings, assesses your little one’s growth and development, and referrals to specific specialists.


Vaccines provide an important line of defense against potentially serious health problems caused by viruses and bacteria. At Happy Bun Pediatrics, expert pediatrician Y.C. Jennie Chung, MD, FAAP, offers vaccines to children of all ages, including hepatitis B, the seasonal flu shot, and varicella. To make an appointment for your child at the practice in McKinney, Texas, call the office or click the online booking tool today.

Vaccines, or immunizations, teach your child’s immune system to identify and attack potentially harmful invaders like viruses and bacteria. They play an important role in preventive health care and significantly lower the risk of potentially serious complications.

By vaccinating your child from an early age, it’s possible to protect their well-being and development. What’s more, vaccines protect the community at large, including your child’s friends and classmates.

Vaccines work by exposing your child to a safe version of a disease in the form of: 

  • A weakened pathogen
  • A dead or inactivated pathogen
  • A toxoid containing toxins from a pathogen
  • A protein or sugar from a pathogen

When these microscopic particles enter your child’s body, they cause their immune system to build an adaptive response. An adaptive response helps the body fight off an infection, limiting uncomfortable side effects and speeding up the natural healing process.

Some of the most common immunizations given to children include:

  • Hepatitis B
  • Rotavirus
  • Diphtheria, Tetanus, and Pertussis (DTaP)
  • Seasonal influenza shot
  • Measles, mumps, rubella (MMR)
  • Polio
  • Varicella
  • Human papillomavirus (HPV)

Following a physical exam, Dr. Chung can make vaccine recommendations that align with your child’s needs.

Vaccines are safe and usually well-tolerated. Before being released to the general public, each vaccine formula undergoes extensive testing by regulatory bodies like the CDC and FDA. 

Side effects do occur on occasion, but they’re usually mild. For example, your child might experience mild swelling or soreness at the injection site. 

No vaccine is 100% effective but most vaccines significantly reduce the risk of illnesses and other related complications. 

Immunizations are especially important for infants, children, and teens because their immune systems are still developing. By minimizing the number of times your child gets sick, it’s possible to protect their health and well-being for years to come. 

A little boy being vaccinated by a doctor as his mom stands next to him
Dr Chung and a young girl having fun in the clinic room after evaluation

Behavioral Consultation

If your child has difficulty sitting still or becomes easily distracted, a behavioral consultation can pinpoint the underlying cause and make recommendations for treatment. At Happy Bun Pediatrics, expert pediatrician Y.C. Jennie Chung, MD, FAAP, provides behavioral consultations and makes the appropriate referral to specialists when necessary to children of all ages. To make an appointment for your child at the practice in McKinney, Texas, call the office or click the online booking tool today.

A behavioral consultation diagnoses and treats medical conditions that cause impulsive or defiant behavior. 

All children experience periods of rebellion or poor focus, but if your child’s behavior interferes with their ability to do school work or spend time with friends, it may point to a more serious issue.

A behavioral consultation can determine the cause of their symptoms and make recommendations to improve their quality of life.

Behavioral consultations diagnose various conditions, but Dr. Chung focuses on three in particular:

Attention-deficit hyperactivity disorder (ADHD)

About 8% of children have ADHD, a behavioral disorder that makes it difficult to focus or pay attention. When left untreated, ADHD can affect their performance in the classroom or their ability to make friends. Fortunately, ADHD is possible to treat through a combination of counseling and prescription medication.

Oppositional defiant disorder (ODD)

Children with ODD display an intense distaste for people in authority, like their parents, teachers, or coaches. Common signs of ODD include frequent temper tantrums, a spiteful or vindictive attitude, and provocative behavior, like purposely annoying siblings or friends.

Conduct disorder (CD)

Conduct disorder causes children to break social norms or the rights of their peers. Examples of CD include destruction of property like setting fires or vandalism, rule-breaking like not going to school, and lying or deceiving others.

At Happy Bun Pediatrician, a behavioral consultation begins with Dr. Chung conducting a physical and neurological exam. Afterward, she has you fill out several standardized questionnaires and checklists about your child’s behavior. 

After analyzing your responses and assessing your child’s medical history, Dr. Chung develops a custom treatment plan. Often, that involves healthy lifestyle changes, behavioral therapy, and prescription medication.

Dr. Chung typically recommends behavioral consultations for children who are school-aged or older. That’s because kids who are four or younger tend to exhibit a variety of behaviors that aren’t necessarily abnormal. Lack of sleep, underlying physical health problems, and the inability to fully communicate can all contribute to yelling, crying, or throwing fits as indicated. 


Many schools and youth sports teams require students and athletes to undergo physicals at least once a year. Routine checkups can alert you to potential issues and provide guidance on injury prevention. At Happy Bun Pediatrics, expert pediatrician Y.C. Jennie Chung, MD, FAAP, provides school, sports, and traditional physicals to children of all ages. To make an appointment for your child at the practice in McKinney, Texas, call the office or click the online booking tool today.

Physicals are routine checkups that assess your child’s health as well as their ability to play sports or participate in other social activities. Though similar to a well child exam, there are a few minor differences.  

Scheduling a physical for your child at least once a year is an easy way to protect their well-being. It presents an opportunity to ask questions, prepare for the upcoming school year or athletic season, and build a relationship with Dr. Chung. 

At Happy Bun Pediatrician, Dr. Chung uses physicals to:

  • Check for possible illnesses or injuries
  • Identify issues that might become more serious in the future
  • Update your child’s vaccines
  • Educate your child on the importance of nutrition and exercise
  • Depending on your child’s needs, Dr. Chung might also include a behavioral consultation.

At Happy Bun Pediatrician, Dr. Chung offers several types of physicals, including:

School physicals

A school physical is a preventive health measure that updates your child’s vaccines and provides screenings. Most public, private, and charter schools require all students to receive certain immunizations before enrolling. 

To ensure your child performs in the classroom, it’s also important to assess their hearing, vision, and ability to pay attention. If your child has astigmatism, they might have difficulty seeing the chalkboard. If they’re unable to hear clearly, they might misunderstand their teacher’s instruction.

Following a school physical, Dr. Chung provides you with the necessary paperwork to submit to your child’s school administration.

Sports physicals

Sports physicals are preventive exams that determine if your child is healthy enough to participate in athletic activities. During a sports physical, Dr. Chung conducts an exam and reviews your child’s medical history. Afterward, she makes exercise and equipment recommendations to lower the risk of an accident or injury.

If necessary, she can also sign off on any paperwork required by your child’s sports team.  

Yes. Even if your child appears healthy, it’s important to invest in routine checkups. Potentially serious health problems like diabetes, high blood pressure, and ADHD don’t always present obvious symptoms. Dr. Chung can pinpoint them early on when they’re most responsive to treatment.

A child being held by his mom as the doctor checks his heart rate
A child getting her temperature checked by a doctor with an infrared themometer, they are both wearing masks

After Hours Care

If your child sprains an ankle or develops a high fever in the evening or on the weekend, after hours care can provide immediate diagnosis and treatment. At Happy Bun Pediatrics, expert pediatrician Y.C. Jennie Chung, MD, FAAP, offers after hours care via telemedicine to you at your home to infants, children, and teens. To make an appointment for your child with our Pediatrician in McKinney, Texas, call the office today.

After-hour fees, copays, and deductibles apply.

After hours care refers to medical treatment that occurs after 5pm, before 8am, or on a holiday or weekend. It provides diagnosis and treatment of potentially serious but non-life-threatening acute injuries and illnesses. 

At Happy Bun Pediatrician, Dr. Chung understands that children develop fevers and experience accidents at all times of the day and night. She offers after hours care to ensure your child receives the treatment they need, exactly when it’s needed.

At Happy Bun Pediatrician, Dr. Chung uses after hours care to treat various issues, including:

  • Allergic reactions 
  • Asthma
  • Cuts, burns, and bug bites
  • Colds and the flu
  • Pink eye
  • Ear infections
  • Bronchitis
  • Strep throat
  • Sinusitis

Your child might also benefit from after hours care if they experience a sports-related injury like a fracture, strain, or sprain.

At Happy Bun Pediatrician, Dr. Chung understands that children develop fevers and experience accidents at all times of the day and night. She offers after hours care to ensure your child receives the treatment they need, exactly when it’s needed.

After hours care is different from the emergency room in that it provides immediate treatment of non-life-threatening illnesses and injuries. Though emergency rooms are open late, they see people based on their level of need. That means if someone comes in experiencing a heart attack, they’ll take priority over your child. 

After hours care is more affordable than a trip to the ER. It’s covered by most health insurance plans and, according to studies, is up to 10 times cheaper.  

Most minor illnesses and injuries respond well to conservative, at-home treatments like over-the-counter pain medication, rest, and drinking plenty of fluids. But if your child’s symptoms persist or worsen, and it’s outside of normal business hours, contact Happy Bun Pediatrician right away.

Dr. Chung regularly sets aside time for after hours appointments, including at night and on the weekends. If you’re unable to visit the office, she even makes home calls, ensuring the process is convenient.  

No two after hours care appointments are exactly alike. Dr. Chung tailors the consultation to your child’s needs. Often, that includes a physical exam and a review of their health history. 

Afterward, Dr. Chung asks you a series of questions, including when the symptoms first started, if they were triggered by anything, and if it’s a new or ongoing problem.

Sick Visits

When you or your kids aren’t feeling well and home care isn’t working, you can count on Jennie Chung, MD, FAAP, for help. At Happy Bun Pediatrics in McKinney, Texas, Y.C. Jennie Chung, MD, FAAP, offers sick visit appointments for children of all ages. Using on-site diagnostics, she can quickly confirm your child’s condition and customize treatment to help them get better quickly. Schedule a sick visit for your child today using the online booking feature or by calling the office.

Generally, you should schedule a sick visit with Dr. Chung when your child has symptoms that aren’t getting better with at-home care and last longer than a few days.

If you have a newborn or infant who’s ill, it’s best to schedule an evaluation at Happy Bun Pediatrician as soon as possible.

Some of the most common reasons for scheduling a sick visit include:

  • Fever
  • Diarrhea
  • Vomiting
  • Infection
  • Skin rashes
  • Sore throat
  • Colds and flu
  • Unexplained pain

Dr. Chung can also evaluate cuts and abrasions that occur due to accidents like falls or sports injuries.

Dr. Chung discusses the symptoms and reviews your child’s medical history information. Based on the symptoms and their severity, she may make a diagnosis after a physical exam or wait for diagnostic testing results to confirm conditions like strep throat or infection.

Dr. Chung creates a treatment plan that focuses on resolving symptoms quickly and helping your child feel better. She may recommend over-the-counter or prescription medications and rest for colds and flu. For infections, Dr. Chung may prescribe a course of antibiotics.

To prevent infection from cuts or skin injuries, Dr. Chung may apply topical medications and a bandage. If broken or fractured bones are possible, she may refer you for additional treatment with a specialist.

If your child has a family history or other underlying risk factors for chronic diseases, like diabetes, Dr. Chung may also recommend blood work and other screenings to identify diseases in their earliest stages.

When you have an existing health condition, you may need more frequent visits at Happy Bun Pediatrician, so Dr. Chung can evaluate your current treatment and the progression of your disease.

A sick, young girl in bed while her dad takes care of her and gets her medication ready


We totally love Dr. Chung. She is knowledgeable and answers all our questions patiently. We would totally recommend Dr. Chung if you want excellent care for your little one.

Kanupriya P.

Dr Chung is the best, most compassionate, most mindful provider for my kid. We love her and don’t mind the extra drive to have the opportunity for her to care for my kid.

Amy T.

Dr. Chung is excellent! She has been our Pediatrician for years. WE LOVE how nice and how gentle she is with the kids. She listens to our concerns. Highly recommend  to be your children’s Pediatrician.

Susie C.