|
| AD | LPP |
|
Clinical features | | |
|
Gender | Female predominance | Female predominance |
|
Fitzpatrick skin type | Type III-IV | Type III-IV |
|
Pruritus | Less common | More common |
|
Associations | Hypothyroidism | Lichen planus, lichen planopilaris, viral hepatitis |
|
Site | (i) Trunk and proximal extremities | (i) Face and neck, flexural areas, sun-exposed areas |
(ii) Symmetrical distribution | (ii) Symmetrical distribution |
|
Characteristics | (i) Ill-defined slate-grey macules or patches | (i) Ill-defined dark-brown or bluish-brown macules or patches |
(ii) Early lesion may have erythematous rim | (ii) May have different morphologies including diffuse, linear, reticular, follicular, or blotchy |
(iii) May have guttate hypopigmentation |
|
Histopathologic features | | |
|
Epidermis | (i) Mostly normal | (i) Focal epidermal hyperkeratosis and hypergranulosis |
(ii) Few apoptotic keratinocytes | (ii) Few apoptotic keratinocytes |
|
Basal vacuolization | Present in almost all cases, focal distribution | Present in most cases, can be focal or diffuse |
|
Lichenoid dermatitis | Uncommon | Present in half of the cases, mostly focal |
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Superficial lymphocytic infiltration | Mild | Moderate to severe |
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Perifollicular lymphocytic infiltration | None | Present, may develop into perifollicular fibrosis |
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Pigmentary incontinence | Mild-moderate | Moderate-severe |
|