| • | chronic form of "pityriasis lichenoides" (see below) |
| • | recurrent crops brown/ red flat, scaly papules that gradually arise and regress over weeks to months |
| • | chronic lesions à may resolve leaving hypopigmented macules (“spotted leopard”) |
| • | …this is sometimes the presenting complaint (therefore, in ddx for “white spots”) |
PLC ddx:
| • | small plaque parapsoriasis – older patients with parapsoriasis; lesions at different stages of evolution and hypopigmentation in PLC |
| • | secondary syphilis – monomorphous eruption; check palms, soles and mucous membranes |
| • | guttate psoriasis – a more uniform morphology |
| • | PR – herald patch, larger lesions, self-limited |
"Pityriasis Lichenoides"
| • | reccurrent crops of spontaneously regressing papules |
| • | therefore polymorphous, lesions of different age |
| • | all age groups, but more common in first few decades |
| • | T-cell gene rearrangement demonstrate clonal populations of T-cells in select cases |
| • | but shows no significantly documented association with malignant lymphoma |
| • | PLC may regress in months or persist for years (PLEVA usually has a shorter duration) |
| • | spectrum of disease with a variable clinical presentation ranging from mostly acute lesions to mainly chronic lesions |
treatment:
| • | phototherapy provides the best therapeutic response |
| • | high dose tetracycline *not in children < 8years old, nor in pregnant women (2g/day) or erythromycin X 2 months |
histology:
| • | (CD8 lymphocytes predominate in PLEVA; CD4 in PLC) |
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