The young woman has a malar rash (the so-called "butterfly" rash because of the shape across the cheeks). Such a rash

suggests lupus. Discoid lupus erythematosus (DLE) involves mainly

just the skin and is, therefore, relatively benign compared to systemic lupus erythematosus (SLE). In either case, sunlight exposure accentuates this

erythematous rash. A small number (5 to 10%) of DLE patients go on to

develop SLE (usually the DLE patients with a positive ANA).

Histologically, the skin in SLE may demonstrate a vasculitis and dermal chronic inflammatory infiltrates, as seen here. Vasculitis with autoimmune disease can occur in many different organs and can lead to the often confusing signs and symptoms of patients with rheumatic diseases.

Here is a more severe inflammatory skin infiltrate in the upper dermis of a patient with SLE in which the basal layer is undergoing vacuolization and dissolution, and there is purpura with RBC's in the upper dermis (which are the reason for the rash).

The periarteriolar fibrosis ("onion skinning") seen in the spleen in patients with SLE at autopsy is quite striking, though of no major clinical consequence. This results from vasculitis.

One of the feared complications of the rheumatic diseases is renal failure. This is most likely to occur with SLE. Here is a glomerulus in which the capillary loops are markedly pink and thickened such that capillary lumens are hard to see. This is lupus nephritis.

Here is a glomerulus with thickened pink capillary loops, the so-called "wire loops", in a patient with lupus nephritis. The surrounding renal tubules are unremarkable.

At low magnification, the collagen of the dermis is increased. Chronic inflammatory cells are sparse with systemic sclerosis, unlike SLE.

This is contact dermatitis, a form of type IV hypersensitivity in which pre-sensitized lymphocytes led to this inflammatory reaction

The acute laryngeal edema seen here that killed the patient was due to an anaphylactic reaction to penicillin. Such an allergy is a form of type I hypersensitivity reaction in which there is preformed IgE antibody on mast cells that quickly reacts with an antigen. The mast cells release histamine and other mediators that lead to the edema.

This is a peculiar disease known as amyloidosis. Amyloidosis is characterized by slow deposition over years of increasing amounts of an amorphous proteinaceous material in one or more tissues. Seen here in the heart between the darker red myofibers are pale pink amyloid deposits.

Hashimotos thyroiditis