Measles (Rubeola)
The most likely diagnosis is measles (rubeola), given the classic presentation of prodromal symptoms (cough, high fever, runny nose, conjunctivitis) followed by an erythematous maculopapular rash that begins at the hairline and spreads cephalocaudally, combined with documented exposure to a similar illness in a close contact. 1
Clinical Presentation Confirming Measles
The patient demonstrates the pathognomonic sequence of measles infection:
Prodromal phase: The initial symptoms of cough, coryza (runny nose), and conjunctivitis with high fever represent the classic "3 Cs" that precede the rash by several days 1, 2, 3
Rash characteristics: The erythematous maculopapular rash appearing at the hairline and spreading downward to involve the face, trunk, and extremities while becoming confluent is the hallmark distribution pattern of measles 1, 4
Timing: The 4-day interval between prodromal symptoms and rash onset aligns precisely with typical measles progression 1, 2
Epidemiologic link: The documented similar illness in a dormitory mate 2-3 weeks earlier establishes a clear transmission chain, as measles patients are contagious from 4 days before until 4 days after rash appearance 1
Key Distinguishing Features
Look for Koplik spots (small white spots with red halos on the buccal mucosa), which are pathognomonic for measles and appear during the prodrome, though they may fade as the rash develops 1, 4
The college dormitory setting represents a high-risk environment for measles transmission, particularly among unvaccinated or inadequately vaccinated young adults, as up to 5% of individuals who received only a single vaccine dose can experience primary vaccine failure 1
Diagnostic Confirmation
Laboratory confirmation should include 2, 4:
- Measles-specific IgM antibody testing in serum, dried blood spots, or oral fluid
- Detection of measles virus RNA by reverse transcriptase-polymerase chain reaction from throat/nasopharyngeal swabs, urine, or oral fluid
- Four-fold or greater increase in measles-specific IgG between acute and convalescent sera
Immediate Management Actions
Isolate the patient immediately to prevent further transmission, as measles is one of the most contagious infectious diseases 1, 3
Treatment is primarily supportive 2, 4:
- Vitamin A supplementation (particularly important for reducing complications)
- Monitoring for secondary bacterial infections requiring antibiotics
- Symptomatic management of fever and respiratory symptoms
Critical Complications to Monitor
Neurological complications, though uncommon, can be severe and include acute disseminated encephalomyelitis (ADEM), measles inclusion body encephalitis (MIBE), and subacute sclerosing panencephalitis (SSPE) occurring months to years later 2, 5
Other common complications include otitis media, laryngotracheobronchitis, pneumonia, stomatitis, and diarrhea requiring appropriate monitoring and treatment 2
Public Health Response
Report this case immediately to public health authorities and identify all contacts in the dormitory for immunity assessment through vaccination records or serologic testing 1
Exposed individuals without documented immunity should receive post-exposure prophylaxis with MMR vaccine within 72 hours of exposure or immunoglobulin within 6 days for those with contraindications to vaccination 1