Table 4

 The main important conditions to be distinguished in a patient presenting with a rash and/or itching

Rash+/−itchItching alone
Immune system mediated Immune system mediated
Anaphylactoid reactionAnaphylactoid reaction
Allergic reaction—local Systemic
Urticaria (“hives”) and/or angioedema Idiopathic thrombocytopaenicSystemic upset (for example, uraemia, cholestasis, blood disorders)
purpura (ITP) Other
Infective Senile itch
BacterialSolid tumours
    Meningococcal septicaemiaHIV
    Scarlet fever
    Varicella zoster
        Primary infection (chickenpox)
        Reactivation (herpes zoster or “shingles”)
    Rubella (German measles)
    Non-specific viral rash
Other conditions
    Henoch Schonlein purpura