Chondrodermatitis nodularis chronica helicis (CNH) is a benign inflammatory condition that affects the skin and cartilage of the pinna. CNH is also known as Winkler disease, based on the name of the dermatologist who first described the condition in 1915. It was later defined in 1918 by Foerster, who also outlined the microscopic, clinical, and treatment details of the disease.
This condition commonly affects the helix of the pinna, though in certain cases, the antihelix also may be affected. For this reason, some have suggested renaming the condition chondrodermatitis nodularis auricularis. Other synonyms for the condition are chondrodermatitis nodularis chronica helicis, ear pressure sores, and chondrodermatitis nodularis anti helicis.
The exact etiology behind the development of CNH remains unclear. Most believe it is caused by chronic and excessive pressure on the pinna. Same-side sleeping usually causes this pressure. Other causes of pressure include the continuous and prolonged use of hearing aids, headphones, and other headgear. CNH also may be associated with autoimmune and connective tissue disorders like autoimmune thyroiditis, lupus erythematosus, dermatomyositis, and scleroderma, especially among young females. Anatomical features like the grossly protruding helix or antihelix of affected individuals also have been considered as contributory factors by some. Additional predisposing factors include repeated trauma, actinic damage, and exposure to cold weather.
Furthermore, pinna has certain peculiar anatomical features which make it vulnerable to the development of CNH. These include little subcutaneous tissue and limited blood supply. Little subcutaneous tissue offers minimal cushioning and padding to underlying cartilage. This increases the chances of pressure and cold-induced damage. Limited blood supply further adds to the problem by causing a delay in the healing process and enhancing the chances of ischemia.
CNH is probably a disease of common occurrence, but it is infrequently documented in the literature. Therefore, the exact incidence of CNH remains unknown. This disease commonly affects men of middle-age or elderly but may affect women and younger adults. CNH can occur in all the ethnicities; however, it is more frequent among fair-skinned people with a history of chronic sun exposure.
The exact pathomechanism behind CNH development remains unknown; however, several theories have been proposed. Perichondrial vasculitis theory, reported in 2009 is the latest among all. According to this theory, the disease process begins secondary to the mentioned predisposing factors which cause arteriolar narrowing in the region of perichondrium, farthest from the arterial supply (helix). This leads to ischemia, necrosis, and extrusion of underlying cartilage. Ultimately, foreign body reaction sets in, resulting in severe inflammatory reaction and development of CNH.
The classical histopathology shows hyperkeratosis, parakeratosis with adjacent hyperplasia of the epithelium, and substantial destruction of dermal tissue which is usually lined by sclerosis. Other features include the proliferation of dermal vessels and destruction of underlying cartilage.
CNH patients typically present with the complaint of a spontaneously appearing painful nodule on the helix or antihelix of the pinna. CNH is mainly located on the ear of the usual sleeping side, predominantly the right one. CNH classically presents unilaterally. Nevertheless, bilateral ear involvement may also be observed. Previously mentioned predisposing factors usually precipitate onset. The nodule grows rapidly and then stabilizes after attainment of maximum size. Nocturnal pain is the most frequent symptom with only a few cases presenting with daytime pain, occurring with touching.
Physical examination reveals a single oval or round shaped nodule with raised, rolled edges and an ulcer or crust in its center. The lesion has a diameter of 4 mm to 6 mm and is typically surrounded by an erythematous area. The most common site is the apex of the helix. The nodule is firm, tender and usually fixed to the auricular cartilage on palpation. Removal of the central crust reveals a small channel. Other associated features include bleeding and exudate on the removal of the crust. Distribution on the antihelix is more common among females than among males. Location on rare sites like the external auditory canal and posterior part of the pinna has been reported.
Diagnosis of CNH can begin with a clinical examination. Histopathological confirmation by skin biopsy is the substitute method of diagnosis. Some recommend investigations to rule out systemic illness like scleroderma, thyroid disease, and other collagen vascular diseases especially in young adults presenting under 40 years of age.
There are several therapeutic options for the management of CNH. These can be broadly divided into conservative treatment and surgical excision.
Many techniques have emerged over the years for surgical excision of CNH. These include large excision followed by ear reconstruction using skin grafts or local flaps, removal of the lesional skin and cartilage, as well as techniques of cartilage-only removal with skin-sparing. Most of the studies agree that the simple approach with primary excision and meticulous trimming of cartilage is preferred as the method of choice.
CNH may be confused with a malignant skin condition like basal cell carcinoma due to its nodular appearance and central crusting. Larger and inflamed lesions may mimic squamous cell carcinoma. Gouty tophi is another differential diagnosis; however, unlike CNH, tophi are multiple and occur on other sites like finger and toes.
Keratoacanthoma grows much faster than CNH, and classical resolution after a few months is the characteristic feature which helps to differentiate this condition. CNH lesions with predominant keratosis may resemble seborrheic or keratotic dermatitis.
CNH has a good prognosis, although long-term morbidity is common. Spontaneous resolution is extremely rare. Remission is commonly seen among inadequately treated cases.