||Relapsing polychondritis is an episodic and generally progressive inflammation of the cartilaginous structures throughout the body. It appears to be an autoimmune disease, since in patients with this condition, circulating antibodies to Type II collagen (a type of collagen only present in cartilage), have been detected.
Clinically, relapsing polychondritis is characterized by bilateral auricular chondritis, nasal chondritis, laryngeal chondritis, polyarthritis, respiratory tract chondritis, and ocular inflammation. There is 25% mortality in relapsing perichondritis and this is usually due to involvement of the respiratory tract or cardiac valves. In severe cases of relapsing polychondritis, steroid therapy can be lifesaving.
The involvement of the auricular cartilages is characterized by recurring attacks of painful erythema and edema.
As the cartilage degenerates, the ears become soft and flabby and the normal framework of the pinna collapses. Cutaneous lesions resembling erythema nodosizm occasionally occur.
Histologically, relapsing polychondritis is characterized by chondrolysis associated with perichondritis. The perichondrium is densely infiltrated with both acute and chronic inflammatory cells, which encroach upon the underlying cartilage. The underlying cartilage gradually undergoes degeneration and is replaced by fibrous tissue.
An elastic stain will show clumping and destruction of the elastic fibers within the involved cartilage.
The cutaneous lesions display the changes of a vasculitis, with occlusion of the lumina and an infiltration of lymphocytes and eosinophils.
The skin overlying the upper two-thirds of the pinna is both edematous and erythematous.