Differentials
Lichen simplex chronicus
SIGNS / SYMPTOMS
Lichenified or thickened papules and plaques arising as a consequence of chronic rubbing.
INVESTIGATIONS
Standard histology shows compact orthokeratosis, psoriasiform acanthosis of the epidermis, vertically oriented dermal blood vessels and collagen in the papillary dermis.[54]
Psoriasis
SIGNS / SYMPTOMS
Anatomic distribution favouring extensor surfaces of extremities; silver scale overlying plaques; reports of pinpoint bleeding within plaques.
INVESTIGATIONS
Standard histology shows regular acanthosis, loss of the granular layer, thinning of the supra-papillary plates, dilation of blood vessels in the superficial papillary dermis, neutrophilic abscesses in the stratum corneum and/or parakeratosis.[54]
Lichen planus pemphigoides
SIGNS / SYMPTOMS
Tense bullae on normal skin or skin affected by lichen planus.
INVESTIGATIONS
Standard histology shows cell-poor sub-epidermal bullae, often with lichenoid infiltrates at the bulla edges; eosinophils and neutrophils are also occasionally present.[54]
Direct immunofluorescence shows linear IgG and C3 at the basement membrane zone with lichen planus pemphigoides.
Indirect immunofluorescence using salt-split skin substrate causes immunofluorescence to localise at the roof of blisters.[54]
Granuloma annulare
SIGNS / SYMPTOMS
May resemble annular lichen planus clinically but there is an absence of epidermal changes such as scale and Wickham's striae.
INVESTIGATIONS
Standard histology shows the presence of palisading granulomas surrounding necrobiosis with mucin.[54]
Lichen sclerosus
SIGNS / SYMPTOMS
Causes inflammation, pallor, ecchymoses, fissures, ulceration, and scarring of the genital mucosa. Does not usually affect the mucous membranes. More responsive to treatments than genital LP.
INVESTIGATIONS
Standard histology shows lichenoid lymphocytic infiltrates below homogenised collagen and oedema in the superficial dermis.[54] Epidermal atrophy and perivascular lymphocytic infiltrates in the mid-dermis may be observed, dependent on the age of the lesions.
Lichenoid drug eruption
SIGNS / SYMPTOMS
History reveals use of the associated drug; the most frequently associated drugs include ACE inhibitors, thiazide diuretics, antimalarials, beta-blockers, gold salts, penicillamine, immune checkpoint inhibitors, tyrosine kinase inhibitors, and tumour necrosis factor (TNF)-alpha antagonists.[34][45]
Other drugs have been associated with lichenoid eruptions of the oral mucosa (e.g., allopurinol, ketoconazole, non-steroidal anti-inflammatory drugs [NSAIDs], anticonvulsants, antiretrovirals).[34][45]
Lichenoid keratosis
SIGNS / SYMPTOMS
Single lesion manifestations.
INVESTIGATIONS
Standard histology shows findings of lichen planus but from a single lesion.
Chronic graft versus host disease (lichenoid variant)
SIGNS / SYMPTOMS
Typical lesions usually affect dorsal aspects of hands, feet, and trunk.
Protracted disease course.
INVESTIGATIONS
Histology closely resembles idiopathic LP. The lymphocytic infiltrate is less intense and shows predominantly CD 8+ cells.
Use of this content is subject to our disclaimer