Predominantly on ankles and volar surface of wrists
Four “P’s”
Pruritic
Purple
Polygonal
Papules or plaques
Wickham’s striae: Fine white lines visible on surface of papules or plaques
Koebner reaction: Lesions develop in areas of trauma (e.g., scratching)
Pruritic
Purple
Polygonal
Papules or plaques
Intensely pruritic, flat-topped plaques
Common sites are extensor surfaces of lower extremities
Violaceous, round or oval, atrophic plaques
Common sites are legs
Often resolution of annular or hypertrophic lesions
Violaceous plaques with central clearing
Common sites are penis, scrotum, and intertriginous areas
Vesicles or bullae within existing lesions
Common sites are legs
Photodistributed eruption of hyperpigmented macules, annular papules, or plaques
Most common in Africa, Middle East, and India
Gray-brown or dark brown macules or patches
Sun-exposed or flexural areas
Pruritus minimal or absent
Erythematous to violaceous papules and plaques
Intertriginous sites (e.g., axillae, inguinal creases, inframammary area, limb flexures)
Hyperpigmentation is common
Scales and erosions may be present<unk>  pemphigoides<unk> -lupus erythematosus overlap syndrome
Nail<unk> 
Varies from minor atrophy to total nail loss
Lichen planopilaris (follicular<unk> 
Keratotic papules that may coalesce into plaques
Classic site is the scalp
May be in other body sites (e.g., Graham-Little-Piccardi-Lasseur syndrome)
Untreated, can result in scarring and permanent alopecia
Oral<unk> 
Painful, frequent loss of appetite
May lead to secondary candida infection
Genital<unk> 
Involves glans of penis or epithelium of vulva, vestibule, vagina, and mouth
Often resistant to treatment
Esophageal<unk> 
Associated dysphagia or odynophagia
Concomitant oral, genital, or cutaneous<unk> 
Otic<unk> 
Erythema, induration, and stenosis of external auditory canal
Thickening of TM
Otorrhea
Hearing loss
Varies from minor atrophy to total nail loss
Keratotic papules that may coalesce into plaques
Classic site is the scalp
May be in other body sites (e.g., Graham-Little-Piccardi-Lasseur syndrome)
Untreated, can result in scarring and permanent alopecia
Painful, frequent loss of appetite
May lead to secondary candida infection
Involves glans of penis or epithelium of vulva, vestibule, vagina, and mouth
Often resistant to treatment
Associated dysphagia or odynophagia
Concomitant oral, genital, or cutaneous<unk> 
Erythema, induration, and stenosis of external auditory canal
Thickening of TM
Otorrhea
Hearing loss
Lichen planus
The differential diagnosis for lichen planus includes:
Lichen sclerosus
Chronic graft-versus-host disease
Tinea corporis
Psoriasis
Vitiligo
Atopic dermatitis