Acute skin eruptions Flashcards
Probability diagnosis
- Varicella (chicken pox)
- Measles
- Rubella
- Erythema infectiosum (‘slapped cheek’ disease)
- Roseola infantum
- Other viral exanthema (e.g. enterovirus)
- Hand, foot and mouth disease
- Pityriasis rosea
- Herpes zoster (shingles)
- Drug reaction (see list)
- Impetigo
- Herpes simplex
- Allergic rash (incl. contact dermatitis)
Skin eruptions common childhood ID
measles
rubella
viral exanthem (fourth syndrome)
erythema infectiosum (fifth syndrome)
roseola infantum (sixth syndrome)
Kawasaki disorder
varicella
Serious disorders not to be missed
Vascular:
- Henoch–Schönlein purpura
- Stevens-Johnson syndrome
- other vasculitides
Infection:
- purpura of meningococcus
- primary HIV infection
- folliculitis (e.g. pseudomonas, staphylococcus)
- secondary syphilis
- scarlet fever
Other:
- erythema nodosum
Pitfalls (often missed)
- Guttate psoriasis
- Epstein–Barr virus (EBV) mononucleosis
- Arbovirus infection (e.g. dengue, Ross River fever,
- Barmah Forest virus, Japanese encephalitis)
- Scabies
- Kawasaki disease
- Eczema herpeticum
- Zoonoses (e.g. listeriosis, Q fever)
- Rarities:
- filovirus haemorrhagic diseases (e.g. Ebola, Marburg virus)
- erythema multiforme
Key history
- Should be adapted to pt’s age as viral exanthema common in children.
- Site & mode of onset, mode of progression and past history (e.g. eczema).
- Constitutional disturbance (e.g. pyrexia, pruritus).
- Drug hx and exposure to irritants.
- Diet including unaccustomed food.
- Herald patch (pityriasis rosea).
- Contact with infectious diseases including child care centres and school.
- Overseas travel.
- Bleeding or bruising tendency.
Key examination
Skin of whole body
Nature and distribution of the rash including lesion characteristics
Nails
Soles of feet
Scalp
Mucous membranes and oropharynx
Conjunctivae, lymphadenopathy, splenomegaly
Key investigations
Many diagnoses are clinical. Consider:
FBE/ESR/CRP
EBV test
HIV test
Serology: for rubella, parvovirus, syphilis and other suspected infections
viral and bacterial cultures.
Diagnostic tips
Be vigilant for the deadly meningococcal septicaemia
- which may present as an erythematous rash initially prior to the development of purpura.
Prescribed drugs are a common cause of rash, especially toxic erythema.
- Examples are antibiotics, especially penicillin, thiazides, anti-epileptics, allopurinol, NSAIDs and other anti-arthritic agents.
