Tests
1st tests to order
swab for Gram stain, culture, and sensitivity (acute or acute-on-chronic)
Test
Should be performed at initial presentation, before commencing antibiotics, in order to establish if MRSA is present.
The nail fold should be cleaned before incising with a number 11 blade or 18-gauge needle (to avoid contaminant). It is important to look for sensitivities because of prevalence of bacterial resistance.
In chronic paronychia, usually no diagnostic tests are needed, and any culture or potassium hydroxide may be misleading unless there is an acute process superimposed on the chronic inflammatory state.
Result
observed bacteria
swab for Tzanck smear (acute, herpetic)
Test
If Tzanck smear is negative, further tests for herpes include direct fluorescent antibody for positive staining of the herpes simplex virus (HSV), culture for HSV, and polymerase chain reaction for HSV.
Result
multinucleated giant cells, inclusion bodies, nuclear molding
Tests to consider
potassium hydroxide or fungal culture (chronic)
Test
No laboratory tests are routinely ordered in chronic paronychia.
Result
Candida colonization (should not be confused with infection)
x-ray
Test
This is required only for resistant or atypical cases.
Result
may detect bone disorder such as osteomyelitis, or mass in an underlying bone disorder
MRI
Test
This is required only for resistant or atypical cases.
Result
may detect bone disorder such as osteomyelitis, or mass in an underlying bone disorder
biopsy of skin/bone
Test
This is required only for resistant or atypical cases. It is performed to rule out malignancy and also to excise chronically inflamed tissue.
Result
may rule out or confirm malignancy
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