Investigations
1st investigations to order
clinical diagnosis
Test
Diagnosis is usually made via history and physical examination alone; however, supporting laboratory studies may help identify contributing aetiologies, especially when refractory to empirical treatment.
Result
laboratory testing is usually performed only after treatment failure
Investigations to consider
fungal culture
Test
Sample to include mucosal surfaces covered by dentures.[21]
May be positive if infectious aetiology.
Result
positive for Candida albicans
bacterial culture
Test
Samples include mucosal surfaces covered by dentures (i.e., oral mucosa), and the nares, to identify staphylococcal colonisation.[21]
May be positive if infectious aetiology.
Result
positive for Staphylococcus aureus
FBC
Test
Helpful to exclude deficiency syndromes as contributing factor, and to guide treatment.[21]
May be low if nutritional deficiency is aetiology.
Result
decreased Hb if nutritional deficiency
serum iron panel
Test
The panel should include iron, TIBC, iron saturation, and ferritin levels.[21]
May be low if nutritional deficiency is aetiology.
Result
decreased iron, iron saturation, and ferritin; increased TIBC
serum vitamin B12
Test
Helpful to exclude B12 deficiency as contributing factor, and to guide treatment.[21]
May be low if nutritional deficiency is aetiology.
Result
decreased if nutritional deficiency
serum folate
Test
Helpful to exclude folate deficiency as contributing factor, and to guide treatment.[21]
May be low if nutritional deficiency is aetiology.
Result
decreased if nutritional deficiency
serum zinc
Test
Helpful to exclude zinc deficiency as contributing factor, and to guide treatment.[21]
May be low if nutritional deficiency is aetiology.
Result
decreased if nutritional deficiency
fasting plasma glucose
Test
May be elevated in diabetes, producing an immunosuppressed state.[21]
Result
elevated if diabetes
HbA1c
Test
May be elevated in diabetes, producing an immunosuppressed state.[21]
Result
elevated if diabetes
HIV test
Test
In immunosuppressed patients, annular cheilitis appears readily.
In recurrent or recalcitrant cases, consider test.[21]
Result
may be positive
biopsy
Test
Utilised to rule out malignancy, especially if chronic unilateral lesion.
Result
may be dysplastic or cancerous cells
patch testing
Test
May be indicated in patients with recalcitrant disease in order to help with the avoidance of allergens.
Result
positive reactions if allergic aetiology
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