measles – If the illness is acute and rapid confirmation is required, nasopharyngeal aspirate and a urine test for viral detection are indicated.

conjunctivitis – If the infection is recurrent or persistent, a conjunctival swab test for microscopy and culture for bacteria, along with virus detection and culture, are recommended.

arthritis – In a case such as this, diagnostic imaging and pathology tests are needed to achieve diagnosis, and assessment of severity and complications. Clinical assessment is also needed to monitor progress of the disease and the effect of drug therapy.

laryngitis – For a viral infection, nasopharyngeal aspirate is used for analysis, if available, along with a throat swab for culture.

melanoma – The diagnostic test used here would be an excisional skin biopsy and, if appropriate, a lymph node biopsy.

eczema – For diagnosis, skin prick allergen testing would be used, with a variety of allergens, as appropriate. A skin biopsy can also be considered if the case is severe and diagnosis is uncertain.

diarrhoea – Testing is only indicated when the condition is severe or persistent, or when an epidemic is suspected.

asthma – Clinical assessment and lung function testing are required. In acute cases, arterial blood gas and haemoximetry may be required.