Q: My 6-month-old caught a cold from their sibling, has had phlegm and been on antibiotics for 15 days. Is this normal?
- Myeongchan Kim, MD
- Jun 10
- 3 min read
Updated: Jul 8
Medically reviewed by Sang Hyun Ahn, MD
Content edited by Myeongchan Kim, MD
This post is a dramatization of a question and answer session experienced by our actual medical reviewers. Please note that this content is for informational purposes only and does not constitute medical advice. Always consult with a qualified healthcare professional for any health concerns or before making any decisions related to your health or treatment.
Question:
My 6-month-old baby caught a cold from their older sibling. The older sibling had a runny nose, cough, and phlegm, but got better after taking medication for a week. The baby started with a runny nose, which progressed to a cough and phlegm, so they were prescribed antibiotics. The antibiotics caused diarrhea, so an anti-diarrheal medication was added and the antibiotic was changed.
However, the cough and phlegm persisted. We went back to the doctor and were told the baby developed a very mild ear infection (otitis media). The doctor prescribed the original antibiotic (the one that caused diarrhea) again, along with an anti-diarrheal. The baby's phlegm isn't improving, and they have been taking medication for 15 days now. Is this normal?
Answer:
It must be very exhausting for you to care for your baby and constantly monitor their symptoms for the past 15 days.
Current Situation Summary
• Your 6-month-old caught a cold, which progressed to a cough, phlegm, and eventually a mild ear infection (otitis media).
• The baby has experienced diarrhea from antibiotics and is currently taking medication for the 15th day with persistent phlegm.
Reassurance & Warning Signs
✅ Respiratory infections in infants can last for 2 to 3 weeks. If your baby is being treated for an ear infection, it is a medical standard to complete the full course of antibiotics as prescribed.
⚠️ See a doctor immediately if you notice any of the following:
• Chest retractions (skin sinking in below the ribs when breathing) or nasal flaring.
• A breathing rate of more than 50 breaths per minute (for a 3 to 12-month-old).
• Bluish lips or nails (cyanosis).
• Feeding drops to less than half the usual amount, and there has been no wet diaper for over 8 hours.
• Fever returns, or the baby becomes unusually lethargic and unresponsive.
• The baby constantly pulls at their ear, fusses excessively, or there is discharge coming from the ear.
Home Care Management
Clearing Phlegm: Use saline nasal drops (3-4 times a day) and gently suction the mucus with an aspirator. Maintain indoor humidity between 40-60% (ensure your humidifier is kept clean). Hold the baby upright for 10-15 minutes after feeding to prevent reflux, which can worsen coughing.
Antibiotics and Anti-diarrheals: Antibiotics for ear infections should be taken until finished as directed by your doctor (usually a 7 to 10-day course). If the diarrhea is not severe and there is no diaper rash, the anti-diarrheal might not be strictly necessary, but please consult your pediatrician before stopping it.
Hydration & Nutrition: Continue breastmilk or formula feeding as usual. If you have started solids, offer easily digestible purees. You can discuss with your doctor whether slightly increasing the ratio of solid foods might help reduce lactose burden during episodes of diarrhea.
Questions to Ask Your Doctor at the Next Visit
• "Since the phlegm has lasted for over two weeks, how is the ear infection responding? Do we need to recheck the eardrum?"
• "Since the diarrhea continues, can we adjust the medication or add probiotics?"
• "How do the chest sounds seem today? Has pneumonia been safely ruled out?"
Follow-up Plan
Your current pediatrician knows your baby's history best, so please follow up with them for a thorough re-evaluation. If the cough and phlegm persist for more than 3 weeks, or if the baby stops gaining weight, your doctor may consider a chest X-ray or an ENT referral. Please continue the home care measures to help clear the phlegm, keep your baby well-hydrated, and seek in-person medical evaluation promptly if symptoms do not improve or if any new warning signs appear.
For extra peace of mind and clear guidance when tracking your child's symptoms, the FeverCoach app is always there to help.
