- Nelson Textbook of Pediatrics, 22nd Edition (2024). Robert M. Kliegman & Joseph W. St. Geme III.
- Red Book: 2024-2027 Report of the Committee on Infectious Diseases, 33rd Edition. American Academy of Pediatrics.
- ABE Guide - Guide to Antimicrobial Therapeutics in Pediatrics. Available at: https://www.guia-abe.es
- UpToDate - Pediatric Infectious Diseases. Wolters Kluwer. Consulted in 2025.
- The Harriet Lane Handbook: The Johns Hopkins Hospital, 23rd Edition (2024).
- Clinical Practice Guideline for the Diagnosis and Management of Acute Otitis Media. American Academy of Pediatrics.
- The Diagnosis and Management of Acute Pharyngitis. Infectious Diseases Society of America (IDSA) Guidelines.
- Management of Community-Acquired Pneumonia (CAP) in Infants and Children Older Than 3 Months of Age. IDSA/PIDS Guidelines.
- Diagnosis and Management of Acute Bacterial Sinusitis in Children Aged 1 to 18 Years. AAP Guidelines.
- Clinical Practice Guideline on Urinary Tract Infection in the Pediatric Population. GuíaSalud, Ministry of Health, Spain.
1. Skin Abscess
Most Common Causative Agent
Staphylococcus aureus (including AC-MRSA).
1st Choice
Incision and Drainage.
Antibiotic (if >5cm, systemic signs, etc.)
Clindamycin: 30-40 mg/kg/day, every 6-8 hours.
Presentations: Sol. 15mg/ml, Cap. 300mg.
Alternative
TMP/SMX: 8-12 mg/kg/day of TMP, every 12 hours.
Presentations: Susp. 40mg+200mg/5ml.
⚠️ WARNING
Do not use beta-lactams alone if CA-MRSA is suspected.
2. Bacterial Cervical Adenitis
Most Common Causative Agent
S. aureus, S. pyogenes.
1st Choice
Amoxicillin-Clavulanate: 45 mg/kg/day, every 12 hours.
Presentations: Susp. 400mg+57mg/5ml.
Alternative/Suspected CA-MRSA
Clindamycin: 30-40 mg/kg/day, every 6-8 hours.
Presentations: Sol. 15mg/ml.
⚠️ WARNING
Consider atypical etiology (Bartonella, Mycobacteria) if there is no response.
3. Streptococcal Tonsillitis (Pharyngotonsillitis)
Most Common Causative Agent
Streptococcus pyogenes (EBHGA).
1st Choice
Amoxicillin: 50 mg/kg/day, every 12-24 hours, 10 days.
Presentations: Susp. 250mg/5ml, 500mg/5ml.
Allergy (non-anaphylactic)
Cefadroxil: 30 mg/kg/day, every 12 hours.
Presentations: Susp. 250mg/5ml.
Allergy (anaphylactic)
Clindamycin: 20 mg/kg/day, every 8 hours.
Presentations: Sol. 15mg/ml.
⚠️ WARNING
Do not use Tetracyclines/Sulfonamides. Most pharyngitis is viral; use quick test.
4. Septic Arthritis
Most Common Causative Agent
S. aureus. Others: Kingella kingae, S. pneumoniae.
Treatment
EMERGENCY. Requires hospitalization, joint drainage and treatment. IV (Cefazolin, Clindamycin or Vancomycin).
Sequential Oral Treatment
Cephalexin: 100-150 mg/kg/day, every 6 hours.
Presentations: Susp. 250mg/5ml.
⚠️ WARNING
Delay in treatment can lead to permanent joint destruction.
5. Asymptomatic Bacteriuria
Definition
Positive urine culture without symptoms of UTI.
Treatment
Antibiotic treatment is not recommended.
⚠️ WARNING
Treating it does not provide benefits and increases resistance. Do not request routine urine cultures in asymptomatic children.
6. Balanitis / Balanoposthitis
Most Common Causative Agent
Irritation + superinfection (Candida, mixed flora).
1st Choice
Hygiene: Sitz baths, keep area clean and dry.
Topical Treatment
Clotrimazole 1% cream. If there is a bacterial component, use combined cream (antibiotic/antifungal/corticoid).
⚠️ WARNING
Do not force the foreskin to retract. Differentiate from paraphimosis (emergency).
7. Blepharitis
Most Common Causative Agent
Inflammation, often with overgrowth of S. aureus.
1st Choice
Eyelid hygiene: Warm compresses and gentle cleaning of the edge of the eyelashes.
Topical Treatment (if persists)
Erythromycin Ointment 0.5% at night.
⚠️ WARNING
Avoid topical corticosteroids without ophthalmological supervision.
8. Bronchiolitis
Most Common Causative Agent
Respiratory Syncytial Virus (RSV).
Treatment
Support. Hydration and oxygenation. Aspiration of secretions.
⚠️ WARNING
Antibiotics, bronchodilators and corticosteroids are not routinely recommended.
9. Acute Bronchitis
Most Common Causative Agent
Predominantly viral. Queer: Mycoplasma, Bordetella.
Treatment
Symptomatic. Antibiotics are usually not indicated.
Consider Antibiotic if...
Suspected pertussis or atypical pneumonia: Azithromycin 10 mg/kg on day 1, then 5 mg/kg/day for 4 days.
Presentations: Susp. 200mg/5ml.
⚠️ WARNING
The indiscriminate use of antibiotics promotes resistance.
10. Infectious Cellulite
Most Common Causative Agent
S. pyogenes, S. aureus.
1st Choice (Non-purulent)
Cephalexin: 25-50 mg/kg/day, every 6-8 hours.
Presentations: Susp. 250mg/5ml.
1st Choice (Purulent / Suspected CA-MRSA)
Clindamycin: 30-40 mg/kg/day, every 6-8 hours.
Presentations: Sol. 15mg/ml.
⚠️ WARNING
Elevate the affected limb. Mark the edges to monitor progression.
11. Periorbital (Preseptal) Cellulitis
Most Common Causative Agent
S. aureus, S. pyogenes.
1st Election (Oral)
Amoxicillin-Clavulanate: 45-90 mg/kg/day, every 12 hours.
Presentations: Susp. 400mg+57mg/5ml, 600mg+42.9mg/5ml.
Alternative/Suspected CA-MRSA
Clindamycin: 30-40 mg/kg/day, every 6-8 hours.
Presentations: Sol. 15mg/ml.
⚠️ WARNING
Differentiate from orbital cellulitis (emergency). Warning signs: proptosis, ophthalmoplegia, eye pain.
12. Cystitis (uncomplicated UTI)
Most Common Causative Agent
Escherichia coli.
1st Choice
Cefuroxime: 20-30 mg/kg/day, every 12 hours.
Presentations: Susp. 125mg/5ml, 250mg/5ml.
2nd Choice
Amoxicillin-Clavulanate: 20-40 mg/kg/day, every 8-12 hours.
Presentations: Susp. 250mg+62.5mg/5ml.
⚠️ WARNING
Avoid Nitrofurantoin in <3 months or suspected pyelonephritis. Quinolones are not 1st line.
13. Bacterial Conjunctivitis
Most Common Causative Agent
H. influenzae, S. pneumoniae, M. catarrhalis.
1st Choice (Topical)
Polymyxin B / Trimethoprim Eye Drops: 1 drop every 3-4 hours.
2nd Choice (Topical)
Erythromycin Ointment 0.5%: Apply 2-4 times/day.
⚠️ WARNING
Neonatal conjunctivitis requires treatment. urgent systemic. Do not use corticosteroids.
14. Croup (Laryngotracheitis)
Most Common Causative Agent
Parainfluenza virus.
Fundamental Treatment
Dexamethasone: Single oral dose 0.15-0.6 mg/kg.
Presentations: Oral sol. 1mg/ml.
Moderate-Severe Croup (Emergencies)
Nebulized adrenaline.
⚠️ WARNING
Antibiotics are not indicated. Cold air can help.
15. Dacryocystitis
Most Common Causative Agent
S. aureus, S. pneumoniae.
Treatment of Mild Cases
Amoxicillin-Clavulanate: 45 mg/kg/day, every 12 hours.
Presentations: Susp. 400mg+57mg/5ml.
⚠️ WARNING
Serious cases require admission and treatment. IV. It can be complicated by periorbital cellulitis.
16. Superinfected Atopic Dermatitis
Most Common Causative Agent
Staphylococcus aureus.
Localized Infection
Mupirocin 2% ointment or corticosteroid+antibiotic cream.
Widespread infection
Cephalexin: 25-50 mg/kg/day, every 6-8 hours.
Presentations: Susp. 250mg/5ml.
⚠️ WARNING
Optimize treatment basis of dermatitis is essential.
17. Lyme Disease
Most Common Causative Agent
Borrelia burgdorferi.
1st Choice
Amoxicillin: 50 mg/kg/day, every 8 hours, 14-21 days.
Presentations: Susp. 250mg/5ml, 500mg/5ml.
Alternative (>8 years)
Doxycycline: 4.4 mg/kg/day, every 12 hours.
Presentations: Comp. 100mg.
⚠️ WARNING
Routine post-sting prophylaxis is not recommended. Doxycycline is avoided in <8 years.
18. Hand-Foot-Mouth Disease
Most Common Causative Agent
Coxsackievirus A16, Enterovirus 71.
Treatment
Symptomatic. Painkillers and a soft, cold diet to avoid dehydration.
⚠️ WARNING
Antibiotics are not effective. Monitor for signs of dehydration.
19. Cat Scratch Disease
Most Common Causative Agent
Bartonella henselae.
Treatment
Self-limited. It does not require antibiotics in most cases.
Antibiotic Indication (Severe disease)
Azithromycin: 10 mg/kg day 1, then 5 mg/kg/day 4 days.
Presentations: Susp. 200mg/5ml.
⚠️ WARNING
Needle aspiration can relieve pain from suppurated lymph nodes.
20. Epiglottitis
Most Common Causative Agent
Post-Hib vaccine: S. pneumoniae, S. aureus.
Treatment
MEDICAL EMERGENCY. Ensure airway and treatment. IV (Ceftriaxone + Clindamycin/Vancomycin).
⚠️ WARNING
NEVER examine the throat outside of a controlled environment. It can cause fatal obstruction.
21. Erysipelas
Most Common Causative Agent
Streptococcus pyogenes.
1st Choice
Amoxicillin: 50 mg/kg/day, every 8 hours.
Presentations: Susp. 250mg/5ml, 500mg/5ml.
Allergy (anaphylactic)
Clindamycin: 20-30 mg/kg/day, every 8 hours.
Presentations: Sol. 15mg/ml.
⚠️ WARNING
Superficial infection with well-defined borders. Common facial location.
22. Scabies (Scabies)
Most Common Causative Agent
Sarcoptes scabiei.
1st Topical Choice (>2 months)
Permethrin 5% cream: Apply all over the body, leave for 8-14 hours and wash. Repeat in 1-2 weeks.
Oral Treatment (>15 kg)
Ivermectin: 0.2 mg/kg, single dose. Repeat in 1-2 weeks.
⚠️ WARNING
Treat all cohabitants simultaneously. Wash clothes and sheets with hot water.
23. Scarlet fever
Most Common Causative Agent
S. pyogenes producer of erythrogenic toxin.
1st Choice
Amoxicillin: 50 mg/kg/day, every 12-24 hours, 10 days.
Presentations: Susp. 250mg/5ml, 500mg/5ml.
⚠️ WARNING
It is a pharyngitis with rash. Treat to prevent rheumatic fever.
24. Herpetic Stomatitis
Most Common Causative Agent
Herpes Simplex Virus type 1 (HSV-1).
Treatment
Support: Pain management and hydration.
Antiviral Treatment (onset <72-96h)
Acyclovir: 15 mg/kg/dose, 5 times/day.
Presentations: Susp. 200mg/5ml.
⚠️ WARNING
Main complication: dehydration.
25. Typhoid Fever
Most Common Causative Agent
Salmonella Typhi.
1st Choice
Ceftriaxone (IV): 50-75 mg/kg/day.
Oral Alternative
Azithromycin: 10-20 mg/kg/day, 7 days.
Presentations: Susp. 200mg/5ml.
⚠️ WARNING
Serious illness. Drug resistance is common. Be guided by local epidemiology.
26. Furunculosis
Most Common Causative Agent
Staphylococcus aureus.
Treatment
Hot compresses. Drain if necessary.
Antibiotics (if infectious cellulitis or recurrence)
Cephalexin or, if you suspect AC-MRSA, Clindamycin.
⚠️ WARNING
In recurrences, investigate and treat nasal carrier state.
27. Bacterial Gastroenteritis
Most Common Causative Agent
Campylobacter, Salmonella, Shigella.
Fundamental Treatment
Oral rehydration.
Antibiotics (specific indications)
Shigellosis or severe Campylobacter: Azithromycin.
⚠️ WARNING
DO NOT use antibiotics if E. coli O157:H7 is suspected (risk of HUS).
28. Giardiasis
Most Common Causative Agent
Giardia lamblia.
1st Choice
Metronidazole: 15 mg/kg/day, every 8 hours, 5-7 days.
Presentations: Susp. 125mg/5ml, 250mg/5ml.
2nd Choice
Tinidazole: 50 mg/kg, single dose.
Presentations: Comp. 500mg, 1g.
Alternative
Nitazoxanide.
⚠️ WARNING
Metronidazole has a metallic taste. Tinidazole has a better regimen and taste.
29. Herpangina
Most Common Causative Agent
Coxsackie A virus.
Treatment
Symptomatic. Painkillers and soft, cold diet.
⚠️ WARNING
It is distinguished from herpetic stomatitis by the posterior location of the ulcers.
30. Shingles
Most Common Causative Agent
Reactivation of the Varicella-Zoster Virus.
Treatment in Healthy Children
Symptomatic. Antivirals are not routine.
Indication of Antivirals
Adolescents, immunocompromised, ophthalmic zoster: Acyclovir 20 mg/kg/dose, 4 times/day.
Presentations: Susp. 200mg/5ml.
⚠️ WARNING
Ophthalmic zoster is an ophthalmological emergency.
31. Impetigo
Most Common Causative Agent
S. aureus, S. pyogenes.
1st Choice (Topical)
Mupirocin 2% ointment.
1st Choice (Systemic)
Cephalexin: 25-50 mg/kg/day, every 6-8 hours.
Presentations: Susp. 250mg/5ml.
⚠️ WARNING
Do not use corticosteroids alone. Removing scabs helps.
32. Superficial Surgical Wound Infection
Most Common Causative Agent
S. aureus, Streptococcus.
Treatment
Cleaning and drainage.
Oral antibiotic (if infectious cellulitis)
Cephalexin: 25-50 mg/kg/day, every 6-8 hours.
Presentations: Susp. 250mg/5ml.
⚠️ WARNING
Deep infection is a surgical emergency.
33. H. pylori infection
Causal Agent
Helicobacter pylori.
Treatment (Triple Therapy)
PPI + Amoxicillin (50 mg/kg/day, every 12 hours) + Clarithromycin (15 mg/kg/day, every 12 hours). 14 days.
⚠️ WARNING
Do not treat functional abdominal pain without warning symptoms.
34. Mastitis
Most Common Causative Agent
S. aureus.
Treatment (Peripubertal)
Amoxicillin-Clavulanate: 25-45 mg/kg/day, every 12 hours.
Presentations: Susp. 250mg+62.5mg/5ml.
⚠️ WARNING
Neonatal mastitis is serious and requires treatment. IV.
35. Acute Mastoiditis
Most Common Causative Agent
S. pneumoniae, S. pyogenes, S. aureus.
Treatment
Hospitalization and treatment. IV (Ceftriaxone +/- Clindamycin/Vancomycin).
⚠️ WARNING
Serious infection with risk of intracranial complications.
36. Bacterial Meningitis
Most Common Causative Agent
>1 month: S. pneumoniae, N. meningitidis.
Treatment
MEDICAL EMERGENCY. Immediate start of treatment. IV (Ceftriaxone/Cefotaxime + Vancomycin).
⚠️ WARNING
Every minute counts. Vaccination is the best prevention.
37. Molluscum Contagiosum
Most Common Causative Agent
Poxvirus.
Treatment
Self-limited. Expectant management is valid.
Therapeutic Options
Curettage, cryotherapy, topical agents (cantharidin, imiquimod).
⚠️ WARNING
Treatment can be painful and leave scars.
38. Infectious Mononucleosis
Most Common Causative Agent
Epstein-Barr virus (EBV).
Treatment
Support: Rest, hydration, pain relievers.
⚠️ WARNING
DO NOT use Amoxicillin/Ampicillin (causes rash). Avoid contact sports due to the risk of splenic rupture.
39. Community Acquired Pneumonia (CAP)
Most Common Causative Agent
Viral, S. pneumoniae, Mycoplasma.
1st Choice (Preschool/Typical)
Amoxicillin: 80-90 mg/kg/day, every 12 hours.
Presentations: Susp. 250mg/5ml, 500mg/5ml.
1st Choice (School/Atypical)
Azithromycin: 10 mg/kg day 1, then 5 mg/kg/day 4 days.
Presentations: Susp. 200mg/5ml.
⚠️ WARNING
The decision of the tto. It is based on age and clinical condition.
40. Omphalitis
Most Common Causative Agent
Polymicrobial (S. aureus, gram-negative).
Treatment (Mild)
Topical antiseptics (Chlorhexidine), Mupirocin.
Treatment (Serious)
Hospitalization and treatment. IV (Oxacillin + Gentamicin).
⚠️ WARNING
Potentially serious infection in the neonate. Low threshold for hospitalization.
41. Osteomyelitis
Most Common Causative Agent
S. aureus.
Treatment
Hospitalization and treatment. prolonged IV (Clindamycin, Cefazolin or Vancomycin).
Sequential Oral Treatment
After improvement, go to oral (Clindamycin o Cephalexin) for 3-6 more weeks.
⚠️ WARNING
Early diagnosis with MRI is key. Long treatment.
42. Otitis Externa (Swimmer's Ear)
Most Common Causative Agent
Pseudomonas aeruginosa, S. aureus.
1st Choice (Topical)
Ear drops with antibiotic and corticosteroid (e.g. Ciprofloxacin/Dexamethasone).
⚠️ WARNING
Ensure that there is no tympanic perforation before using topical aminoglycosides.
43. Acute Otitis Media (AOM)
Most Common Causative Agent
S. pneumoniae, H. influenzae, M. catarrhalis.
1st Choice
Amoxicillin: 80-90 mg/kg/day, every 12 hours.
Presentations: Susp. 250mg/5ml, 500mg/5ml.
2nd Choice (or failure)
Amoxicillin-Clavulanate: 90 mg/kg/day of amoxi, every 12 hours.
Presentations: Susp. 600mg+42.9mg/5ml.
⚠️ WARNING
Consider "Watchful Waiting" in children >2 years with mild AOM.
44. Parotitis (Mumps)
Most Common Causative Agent
Mumps virus.
Treatment
Symptomatic.
⚠️ WARNING
Vaccination (MMR) is the best prevention. Monitor for complications (orchitis, meningitis).
45. Pediculosis (Lice)
Causal Agent
Pediculus humanus capitis.
1st Choice (Topical)
Permethrin 1% o Pyrethrins. Repeat in 7-10 days.
Mechanical Removal
The hairstyle with a haircut is essential.
⚠️ WARNING
Children with lice should not be excluded from school.
46. Pyelonephritis (febrile UTI)
Most Common Causative Agent
E.coli.
Treatment (Oral, if good condition)
Cefixime: 8 mg/kg/day, every 12-24 hours.
Presentations: Susp. 100mg/5ml.
Treatment (Hospital)
Ceftriaxone (IV/IM): 50-75 mg/kg/day, every 24 hours.
⚠️ WARNING
All infants with febrile UTI should be studied with renal ultrasound.
47. Acute Bacterial Sinusitis
Most Common Causative Agent
S. pneumoniae, H. influenzae.
1st Choice
Amoxicillin: 45-90 mg/kg/day, every 12 hours.
Presentations: Susp. 250mg/5ml, 500mg/5ml.
2nd Choice
Amoxicillin-Clavulanate: 90 mg/kg/day of amoxi, every 12 hours.
Presentations: Susp. 600mg+42.9mg/5ml.
⚠️ WARNING
Diagnosis: persistence >10 days, worsening or severe onset.
48. Ringworm (Dermatophytosis)
Most Common Causative Agent
Dermatophytic fungi (Trichophyton, Microsporum).
Ringworm Corporal (Topical)
Topical antifungals (Clotrimazole, Terbinafine).
Tinea Capitis (Systemic)
Griseofulvin: 20-25 mg/kg/day, every 24 hours, 6-8 weeks.
Presentations: Susp. 125mg/5ml.
⚠️ WARNING
Tinea capitis ALWAYS requires treatment. systemic oral.
49. Whooping cough (Pertussis)
Most Common Causative Agent
Bordetella pertussis.
1st Choice
Azithromycin: 10 mg/kg/day, every 24 hours, 5 days.
Presentations: Susp. 200mg/5ml.
Post-exposure prophylaxis
Same deal. to all close contacts.
⚠️ WARNING
Infants <3 months are at high risk of apnea and death.
50. Chickenpox
Most Common Causative Agent
Varicella-Zoster Virus (VZV).
Treatment
Symptomatic.
Indication of Antivirals
>12 years, secondary cases, comorbidities. Acyclovir: 20 mg/kg/dose, 4 times/day.
Presentations: Susp. 200mg/5ml.
⚠️ WARNING
Avoid Ibuprofen due to the risk of serious skin superinfection. Vaccination is the best prevention.