Skip to Main Content


They say love’s like the measles—all the worse when it comes late in life.

Douglas Jerrold (1803–57)

The sudden appearance of a rash, which is a common presentation in children (see CHAPTER 93), usually provokes patients and doctors alike to consider an infectious aetiology, commonly of viral origin. However, an important cause to consider is a reaction to a drug.

A knowledge of the relative distribution of the various causes of rashes helps with the diagnostic methodology. Many of the eruptions are relatively benign and undergo spontaneous remission. Fortunately, the potentially deadly rash of smallpox is no longer encountered.

A list of important causes of acute skin eruptions is presented in Table 124.1.

Table 124.1

Important causes of acute skin eruptions

Serious eruptions not to be missed and pitfalls are outlined in Table 124.2.

Table 124.2

Acute skin eruptions

A diagnostic approach

The diagnostic approach to skin eruptions presupposes a basic knowledge of the causes; a careful history and physical examination should logically follow.

The history should include:

  • site and mode of onset of the rash

  • mode of progression

  • drug history

  • constitutional disturbance (e.g. pyrexia, pruritus)

  • respiratory symptoms

  • herald patch?

  • diet—unaccustomed food

  • exposure to irritants

  • contacts with infectious disease

  • bleeding or bruising tendency

The examination should include:

  • skin of whole body

  • nature and distribution of rash, including lesion characteristics

  • soles of feet

  • nails

  • scalp

  • mucous membranes

  • oropharynx

  • conjunctivae and ...

Pop-up div Successfully Displayed

This div only appears when the trigger link is hovered over. Otherwise it is hidden from view.