In addition to lesions in the typical above-the-neck locations, patients with generalized discoid lupus often have lesions on the thorax and the arms. These patients are often bald, with abnormal skin pigment on their scalp, and have severe scarring of the face and arms. Patients with generalized discoid lupus often have abnormal lab tests, such as an elevated ESR or a low white blood cell count. They also often have auto-antibodies, such as ANA or anti-ssDNA antibody. Childhood
When patients develop discoid lupus in childhood, it differs from typical discoid lupus in several ways. Boys and girls are equally affected, and these patients later develop SLE more often. These patients also typically do not have any abnormal sensitivity to the sun. Special types of discoid lupus lesions
Hypertrophic lupus
Some experts consider hypertrophic lupus erythematosus—which consists of lesions covered by a very thick, keratin-filled scale—an unusual subset of discoid lupus. Others consider it a distinct entity. Lupus profundus
If a patient has discoid lupus lesions on top of lupus panniculitis, they have lupus profundus. These patients have firm, nontender nodules with defined borders underneath their discoid lupus lesions. Systemic lupus erythematosus with discoid lupus lesions
In general, patients with discoid lupus who have only skin disease and no systemic symptoms have a genetically distinct disease from patients with SLE. However, 25% of patients with SLE get discoid lupus lesions at some point as part of their disease.
This finding is 90% sensitive; however, false positives can occur with biopsies of facial lesions. In addition, pathologists often see groups of white blood cells, particularly T helper cells, around the follicles and blood vessels in the dermis. The epidermis appears thin and has effaced rete ridges as well as excess amounts of keratin clogging the openings of the follicles. The basal layer of the epidermis sometimes appears to have holes in it since some of the cells in this layer have broken apart. The remains of skin cells that have died through a process called apoptosis are visible in the upper layer of the dermis and the basal layer of the epidermis.The differential diagnosis includes actinic keratoses, sebborheic dermatitis, lupus vulgaris, sarcoidosis, drug rash, Bowens disease, lichen planus, tertiary syphilis, polymorphous light eruption, lymphocytic infiltration, psoriasis, and systemic lupus erythematosus. Classification
Discoid lupus can be broadly classified into localized discoid lupus and generalized discoid lupus based on the location of the lesions. Patients who develop discoid lupus in childhood also have their own sub-type of disease.Hypertrophic lupus and lupus profundus are two special types of discoid lupus distinguished by their characteristic morphological findings.Finally, many patients with systemic lupus also develop discoid lupus lesions. Localized
Most people with discoid lupus only have lesions above the neck and therefore have localized discoid lupus erythematosus. Generalized
Rarely, patients may have lesions above and below the neck; these patients have generalized discoid lupus erythematosus.