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Tinea%20capitis%20(pediatric) Diagnosis
Assessment
Patterns of Clinical Infection:
- Host T-lymphocyte response determines clinical infection patterns
- Diffuse or patchy, fine, white, adherent scales on the scalp resembling dandruff
- There are tiny, perifollicular pustules &/or hair stubs from the scalp
- Patient has areas of noninflammatory hair loss that are well demarcated; hairs are broken off at the follicular orifice & debris left at the opening appears as a black dot
- Color of “dot” will depend on hair color
- Patient has circular patches w/ hair loss & fine scaling w/c is dull grey in color
- Greying is caused by the spores covering the affected hair
- Intense inflammation manifests as single or multiple boggy, tender areas of alopecia w/ pustules on &/or in surrounding skin
- Hypersensitivity to fungus may form a boggy, indurated, tumor-like mass that exudes pus & referred to as kerion
- Discrete pustules or scabbed areas w/o scaling or significant hair loss
- Pustules result from superimposed bacterial infection
- An inflammatory variant characterized by yellow cup-shaped crusted lesions called scutula
- Commonly seen in the Middle East & North Africa, caused by T. schoenleinii
Laboratory Tests
Microscopy
- Provides the most rapid means of diagnosis but may not always show positive in affected patients
- Scalp scales &/or hair are mounted in 10-30% Potassium hydroxide (KOH) solutionn, gently heated & viewed under light or flourescence microscope
- Positive results reveal hairs &scales invaded by spores &/or hyphae
- Allows accurate identification of organism but results may take up to 4 week
- Use of Sabouraud agar w/ 1 or more plates w/ cycloheximide is recommended
- Results may be positive even when microscopy is negative
- Necessary in hair fungal infections to identify the source of infection & verify the infecting species
- A noninvasive in vivo imaging technique that may aid in the diagnosis of tinea capitis, especially in patients w/ black dot pattern
- Useful for certain ectothrix infections (eg M canis, M audouinii, M rifalieri)
- If present, will cause hair to fluoresce bright green
- T tonsurans, T rubrum & T mentagrophytes, which cause tinea capitis (depending on the region), does not fluoresce
