|
| | 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 |
|
| Superficial lymphocytic infiltration | Mild | Moderate to severe |
|
| Perifollicular lymphocytic infiltration | None | Present, may develop into perifollicular fibrosis |
|
| Pigmentary incontinence | Mild-moderate | Moderate-severe |
|
