Diagnosis of Hypopigmented Tinea Versicolor
The diagnosis of hypopigmented tinea versicolor is made clinically by identifying characteristic hypopigmented macules with fine scale, confirmed by potassium hydroxide (KOH) preparation showing the pathognomonic "spaghetti and meatballs" pattern of short hyphae and spores. 1, 2
Clinical Diagnosis
Key clinical features to identify:
- Hypopigmented macules with fine scale that typically appear on the trunk, shoulders, upper arms, chest, and back 3, 1, 2
- Round or oval lesions that may coalesce into larger patches 1
- Fine scaling that becomes more apparent with gentle scraping 1
- Asymptomatic presentation in most cases, though mild pruritus may occur 1, 2
- Perifollicular hypopigmentation may be seen in folliculocentric variants 4
Important caveat: The hypopigmentation in tinea versicolor can persist for several months even after successful mycological cure, which is critical to explain to patients to avoid unnecessary retreatment 5.
Diagnostic Confirmation Methods
Wood's Light Examination
Wood's light (UV illumination) is useful for:
- Delineating areas of pigment loss that may not be visible in pale skin 6
- Demonstrating the extent of disease 6
- Confirming clinical cure when combined with mycological testing 5
Microscopic Examination (Gold Standard)
KOH preparation is the definitive diagnostic test:
- Apply 10-30% potassium hydroxide to skin scrapings 7
- Look for the characteristic pattern of short, stubby hyphae and spores (described as "spaghetti and meatballs") 1, 2
- Calcofluor white staining can enhance visualization of fungal elements 1
- This provides immediate confirmation and allows treatment initiation 1
Cellophane Tape Test
An alternative collection method:
- Press cellophane tape against the lesion to collect scale 3
- Apply KOH and examine microscopically 3
- This technique was used successfully in clinical trials with high sensitivity 3
Dermoscopy
Dermoscopic findings include:
- Nonuniform perifollicular hypopigmentation with clearly demarcated borders 2
- Patchy scaling 2
- Inconspicuous ridges and furrows 2
Differential Diagnosis Considerations
Tinea versicolor must be distinguished from vitiligo, which is the most common diagnostic confusion with hypopigmented lesions 6. Key differences:
- Tinea versicolor: Fine scale present, KOH positive, typically on trunk 1, 2
- Vitiligo: No scale, complete depigmentation (not hypopigmentation), often symmetrical and involves acral sites 6
Other conditions to exclude include pityriasis alba, postinflammatory hypopigmentation, and idiopathic guttate hypomelanosis 6.
When Histopathology is Needed
Biopsy is rarely required but may be performed in atypical presentations:
- Shows flattening of rete ridges 2
- Demonstrates fungal hyphae and spores in the stratum corneum 2
- Useful when the clinical presentation is atypical (such as atrophic variants) 2
Practical Diagnostic Algorithm
- Identify hypopigmented macules with fine scale on typical body sites (trunk, shoulders, upper arms) 1, 2
- Perform KOH preparation of skin scrapings to confirm presence of hyphae and spores 1
- Use Wood's light if lesions are subtle or patient has fair skin 6, 5
- Consider dermoscopy for additional diagnostic support in unclear cases 2
- Reserve biopsy only for atypical presentations that remain diagnostically uncertain 2
Common pitfall: Do not rely solely on clinical appearance without mycological confirmation, as hypopigmented lesions have a broad differential diagnosis 6, 1.