Fever and a rash

Author: Hon A/Prof Amanda Oakley, Dermatologist, Hamilton, New Zealand, May 2016.

Acute presentation of an unwell patient

Fever most commonly indicates bacterial or viral infection. If there is no systemic sepsis, localised rashes associated with infection tend to cause fewer systemic symptoms than generalised rashes associated with infection. Mucosal involvement is common. There are some acute auto-inflammatory disorders than mimic infection due to neutrophil activation, the neutrophilic dermatoses.

 Consider performing the following tests:

Treatment depends on the cause. Consider referral to emergency department if you are suspicious of serious infection or the patient is very unwell.  

Differential diagnosis


Fever and localised rash

Painful red, hot skin

Prominent blisters/erosions


Purple/black areas

Fever and generalised rash





 May involve mucosal surfaces

Widespread purple/black areas

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