Attenuated atrophic epidermis with interface vacuolar change, ectatic superficial vessels, scattered inflammation, and orthokeratosis are common features of cutaneous lupus. Melanin incontinence is also prominent.
Note the plugged follicle with perifollicular inflammation, commonly seen in discoid lupus. Inflammation to the mid-follicle is present in discoid lupus, which is very important because this area of the follicle contains the bulge that contains the follicular stem cells.
Lupus erythematous is a common systemic autoimmune disorder, most frequently seen in women and blacks. The cutaneous lesions can be classified into acute, subacute and chronic categories. Acute cutaneous lesions are associated with systemic disease whereas in subacute or chronic lesions, systemic disease is usually minimal or absent.
Acute cutaneous LE includes a malar (butterfly) rash or a more morbilliform (measle-like) eruptions. Subacute cutaneous LE includes annular and papulosquamous plaques and generally occur on the trunk and upper extremities. Chronic cutaneous LE includes discoid lupus, tumid lupus and lupus panniculitis. Other lupus cutaneous lesions include bullous LE and neonatal lupus (Busam).
Histologically, most forms of cutaneous lupus share these features: interface dermatitis, necrotic kertainocytes (colloid bodies), vacuolar degeneration at the dermal-epidermal junction, folliculr pluggin, epidermal atrophy OR hyperplasia, melanin incontinence, increased ermal mucin (best seen with Alcian blue or colloidal iron stain for mucin), and perivascular lymphocytes.
Particular to discoid lupus is hyperkeratoisis, more pronounced "carpet-tack" follicular plugging, as well as robust superficial and deep periadnexal lymphocytic infiltrates. Clinically, discoid lupus presents as delineated, circumscribed atrophic plaques, leading to atrophy, dyspigmented and often disfiguring scars (Busam).
Discoid lupus is a chronic, scarring, atrophic dermatosis which can lead to hair loss and hyperpigmentation. It is present both in those with systemic lupus, or it may develop into systemic lupus. Unlike systemic lupus, serologies are typically not abnormal.
The classic lesion is that of erythematous, scaly papules and plaques occurring on sun-exposed areas, although a significant percentage of lesions may be found on hair-bearing scalp.
Ttopical steroids and antimalarials are the main treatments.
Busam KJ. Dermatopathology: Foundations in Diagnostic Pathology 1st Ed. Philadelphia, PA: Elsevier; 2010: 39-41.
Rapini RP. Practical Dermatopathology. Philadelphia, PA: Elsevier; 2005: 223-8.