Differentials
Infectious mononucleosis
SIGNS / SYMPTOMS
Infection with Epstein-Barr virus (EBV) may resemble features of HIV acute seroconversion illness with fever, lymphadenopathy, pharyngitis, and maculopapular rash.
INVESTIGATIONS
EBV IgM serology and Paul Bunnell positive.
HIV test negative (unless HIV coinfection present).
Cytomegalovirus infection (CMV)
SIGNS / SYMPTOMS
May resemble HIV acute seroconversion illness with fever, lymphadenopathy, rash, and splenomegaly.
INVESTIGATIONS
CMV serology positive.
HIV test negative (unless HIV coinfection present).
Influenza infection
SIGNS / SYMPTOMS
No specific differentiating signs; viral infections such as influenza may resemble acute seroconversion illness with fever, pharyngitis, and lymphadenopathy.
INVESTIGATIONS
Influenza viral culture or nucleic acid test (nasopharyngeal or respiratory sample) positive
HIV test negative (unless HIV coinfection present).
Common cold
SIGNS / SYMPTOMS
No specific differentiating signs; viral infections such as the common cold may resemble acute seroconversion illness with fever, pharyngitis, and lymphadenopathy.
INVESTIGATIONS
HIV test negative (unless HIV coinfection present).
Coronavirus disease 2019 (COVID-19)
SIGNS / SYMPTOMS
Important to consider the current epidemiologic situation. May give history of unwell contacts.
Respiratory symptoms may be prominent.
INVESTIGATIONS
Real-time reverse transcription polymerase chain reaction (RT-PCR): positive for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) RNA.
Rapid antigen tests may also be used.
HIV test negative (unless HIV coinfection present).
Viral hepatitis
SIGNS / SYMPTOMS
Right upper quadrant abdominal pain, jaundice.
INVESTIGATIONS
Elevated liver function tests.
Hepatitis B or C serology positive.
HIV test negative (unless HIV coinfection present).
Secondary syphilis
SIGNS / SYMPTOMS
Fever, malaise, pharyngitis, lymphadenopathy, maculopapular rash. Condylomata lata on genital areas and oral ulcers. May have been preceded by painless genital chancre and inguinal lymphadenopathy (primary syphilis). Can coexist with HIV.
INVESTIGATIONS
Venereal disease research laboratory test positive.
Treponema pallidum haemagglutination test positive.
HIV test negative (unless HIV coinfection present).
Use of this content is subject to our disclaimer