The external ear, namely, the auricle and the external auditory canal, is composed of skin, cartilage, and all associated appendages. The skin and cartilage of the ear are subject to the same insults as similar tissues found elsewhere in the body. Thus, many of the diseases discussed below may be found in greater detail in other Medscape Reference articles.
Inflammation is the body's response to cellular injury. The various etiologies that result in inflammation of the ear are numerous and may be categorized broadly as infectious, traumatic, and immunologic. Infectious diseases of the external ear have been covered in other articles and are not discussed here. Inflammation of the auricle may result from trauma (eg, mechanical pressure from telephones or headbands), radiation exposure, or environmental insults or irritants (eg, chemicals used to clean hearing aids). Immune-mediated inflammation includes atopic and autoimmune disorders. As with many diseases, an etiology is not always apparent. These idiopathic disorders have been grouped into a broad fourth category entitled miscellaneous.
Atopic dermatitis, also known as eczema, is a systemic disease that manifests as intensely pruritic, erythematous, skin lesions.  The disease usually manifests in childhood and is more commonly observed in families with a history of asthma, allergic rhinitis, and other atopic disorders. Recent studies indicate that atopic dermatitis may be the result of an altered immunologic balance in which TH 2 cells (a subtype of helper T lymphocytes) predominate. TH 2 cells synthesize interleukins 4, 5, and 10. In psoriasis and allergic contact dermatitis, TH 1 cells, which secrete interferon gamma and tumor necrosis factor, predominate.
The lesions are erythematous scaly crusts and/or small (< 0.5 cm), circumscribed, fluid-filled lesions (vesicles), which may become confluent. Linear fissures may also be noted, often in the postauricular region. Although not specific to atopic dermatitis, affected skin exhibits white dermatographism (ie, appearance of a white line when the lesion is stroked). Chronic scratching often results in thickening (lichenification) of the skin and hyperpigmentation. The skin is particularly susceptible to secondary infection from Staphylococcus aureus; viruses such as herpes simplex virus (HSV), vaccinia, and molluscum contagiosum; and dermatophyte fungi and yeast.
Involvement of the external ear is usually part of a more generalized process that involves the face and neck. Lesions are typically found on the face and on extensor surfaces during childhood and on flexural surfaces (eg, antecubital fossa, popliteal fossa), eyelids, ears, hands, and feet in adulthood. Auricular pseudocyst formation has been reported in patients with atopic dermatitis. These cystic lesions vary from 1.5-3.5 cm in size and typically involve the upper, anterior aspect of the pinna. Patients with atopic dermatitis may be more susceptible to pseudocyst formation as a result of trauma from chronic scratching.
Common triggers for the allergic reaction include certain foods, environmental changes, psychological or emotional stress, airborne allergens, and local skin irritants (especially wool). The most common foods that trigger a reaction include eggs, peanuts, milk, fish, soy, and wheat. In women, menstruation and pregnancy may also trigger or exacerbate symptoms.
History and the characteristic distribution and appearance of pruritic lesions help to make the diagnosis. Laboratory tests that may assist in diagnosis include an elevated plasma histamine level, elevated immunoglobulin E (IgE) level, and peripheral eosinophilia. However, these tests are not specific to atopic dermatitis or even to atopic disorders. Histologic examination of the lesions reveals nonspecific intracellular edema with perivascular lymphocytic infiltration.
Although not essential for making a diagnosis, a patch test or use test may be performed for identification of the allergen or allergens. Patch testing is usually performed on the back or arm and involves subdermal injection of small amounts of allergen. The skin is then observed for an inflammatory reaction. The use test involves the removal of all possible offending agents and a reintroduction of those agents, one at a time, at approximately a 3-day interval, until a reaction is provoked and the allergen is identified. Use testing is often used to identify food allergens. Differential diagnoses include allergic and irritant contact dermatitis, seborrheic dermatitis, neurodermatitis, and psoriasis.
Treatment consists of proper skin care with gentle soaps, moisturizers, topical corticosteroids, and topical tacrolimus. Topical tacrolimus has been shown to decrease production of interleukins IL-4, IL-5, and IL-8, as well as IgE. It is a topical immunosuppressive agent; a burning sensation of the skin is its major side effect. It has relatively poor absorption and, therefore, the side effects often associated with systemic tacrolimus are not seen. In addition to topical medications, oral antihistamines may be administered for relief of pruritus. For skin lesions that are secondarily infected, prescribe saline compresses and topical or oral antibiotics. In severe cases, systemic corticosteroids may be used. Finally, desensitization with immunotherapy may be beneficial in some patients.
Allergic contact dermatitis
Allergic contact dermatitis is a true delayed-type hypersensitivity reaction that occurs when a previously sensitized individual comes in contact with the allergen. Contact allergens are formed when a simple chemical of low molecular weight becomes complexed with a skin protein. Upon reexposure, an inflammatory reaction occurs.
In the acute phase, the skin is erythematous, edematous, and pruritic. Small, raised, circumscribed lesions (papules); weeping fluid-filled lesions (vesicles); exudation; and crusting are present. The lesions may become secondarily infected. In the chronic phase, the skin becomes thickened as a result of chronic rubbing or scratching. Thickening of the skin (lichenification), fissuring, and hyperpigmentation may also be observed.
Allergic contact dermatitis of the external ear is most commonly the result of hair products, cosmetics, earrings, hearing aids, topical medications, cell phones, and other objects that contact the pinna. Paraphenylenediamine, parabens, and quaternium-15, which are ingredients often found in shampoos, hair dyes, and hair sprays, commonly affect the conchae and periauricular regions. Hearing aids made of rubber, vinyl plastics, or methylmethacrylates or chemicals used to clean hearing aids may be the offending agents in cases of contact dermatitis of the external canal. Topical preparations, especially those that contain neomycin and related topical aminoglycoside antibiotics (eg, tobramycin, gentamicin) or topical anesthetic agents, such as benzocaine, may also affect the external auditory canal.
Earrings, especially those made of nickel, cobalt, palladium, or white or yellow gold, may cause dermatitis of the lobule.  In Europe, a new initiative that calls for a reduction in the amount of nickel in commercial products was adopted following Danish studies that revealed a decrease in nickel allergy after a similar initiative was implemented in Denmark. Finally, lesions on the hemilateral pinna or the preauricular region may be the result of an allergy to chromium, a metal commonly used in cell phones. 
In each case, irritated, ulcerated, or inflamed skin appears to increase an individual's likelihood of becoming sensitized to an allergen. When a topical preparation is prescribed, underlying disease is often responsible for irritated inflamed skin within the external auditory canal, along the pinna, or both. Use of hearing aids may occlude the skin within the canal, promoting sensitization of products commonly used to make or to clean hearing aids. In a freshly pierced ear, haptenation is promoted if the dermis comes in contact with a substance such as nickel or gold. Gold sodium thiosulfate, a component of some earrings, has been shown to accumulate in the macrophages of susceptible individuals, resulting in a dense lymphocytic infiltration and pseudolymphoma formation. These pseudolymphomas may present as violaceous, nontender nodules found on ear lobes.
The diagnosis is made with the help of the patient's history and a patch or use test. Patch testing is usually performed on the back or arm and involves subdermal injection of small amounts of allergen. The skin is then observed for an inflammatory reaction. The use test involves the removal of all possible offending agents and the reintroduction of those agents, one at a time, at approximately a 3-day interval, until a reaction is provoked and the allergen is identified. In addition to these 2 tests, a thorough workup includes potassium hydroxide preparation, fungal cultures, Gram stain, and bacterial cultures to exclude a superimposed infection.
In rare instances, a skin biopsy may be performed to identify the lesion. Histopathologic evaluation reveals a dense lymphocytic infiltration with a few eosinophils and plasma cells in the dermis and subcutaneous tissues and lymphoid follicles with germinal centers. T-cell lymphocytic infiltration, especially around blood vessels, is seen in one variant, known as "lymphomatoid contact dermatitis." Clinically and histologically, this can mimic mycosis fungoides and may be considered in the differential diagnosis. Other potential differential diagnoses include irritant contact dermatitis, seborrheic dermatitis, psoriasis, atopic dermatitis, dermatophytosis, infectious eczematoid dermatitis, discoid lupus erythematosus, and angiolymphoid hyperplasia.
Treatment involves avoidance of the offending agent. Silicon hearing aids, which are hypoallergenic, may be substituted in the case of a hearing aid allergy. Using stainless steel earrings until the earring tract has epithelialized adequately may prevent an allergic reaction to earrings. Three weeks is usually appropriate for epithelialization. Cool saline or astringent compresses, topical corticosteroids, aluminum acetate, Burow solution, or Lassar paste can be used for treatment of symptoms. Promptly treat secondary infections with the proper antibiotics. Recent animal studies suggest that blocking IL-18 and IL-12 may be beneficial in the treatment of allergic contact dermatitis.
Photoallergic dermatitis, also known as photodermatosis or solar urticaria, is an inflammatory skin condition that develops when a substance (generally a drug) is altered photochemically so that it haptenates with skin or carrier proteins to form an allergen. The reaction may be elicited when a systemically ingested substance or topically applied substance is altered by blue-violet light (400-500 nm). When the etiologic agent is a topical substance, the dermatitis is considered a true delayed hypersensitivity reaction that requires prior sensitization.
Chemicals that may elicit the reaction include halogenated salicylanilides (found in soaps) and topical phenothiazines and sulfonamides (found in sunscreens). Although chemicals are generally believed to be the causative agents, some evidence suggests that airborne allergens and sunlight may trigger a similar reaction. Often, an etiologic agent cannot be determined.
Photodermatosis of the ears is more common in males. Females tend to have longer hair that covers their ears, preventing sunlight from acting as a catalyst. Lesions may vary in appearance from hives (urticaria) to erythematous, small, raised, circumscribed lesions (papules) and from fluid-filled lesions (vesicles) to scaly, inflammatory, raised lesions (eczematous plaques). Lesions may even be blisterlike in appearance (bullae). Lesions may be pruritic, which usually heal without sequelae. In some individuals, the lesions may persist for months to years.
A diagnosis is made with the help of a history and physical examination. To confirm the diagnosis, a photopatch test may be performed. This consists of the 24-hour application of a standard patch that contains substances such as sulfonamides, phenothiazines, or paraaminobenzoic acid. The patch is then exposed to UV-A light of 5-15 J/m2 and then read again in 48 hours. The patch test is compared with an area of skin that is exposed only to UV-A light and to an area of skin that has been treated with a nonirradiated patch. Differential diagnoses include lupus erythematosus, porphyria, contact and atopic dermatitis, and phototoxic dermatitis.
Primary treatment is avoidance of the etiologic agent and of sunlight. In addition, cold saline compresses or tap water compresses and topical corticosteroids may be applied for relief of symptoms.
Psoriasis (see Psoriasis, Guttate) is a chronic inflammatory skin disorder with 2-5% prevalence. One third of patients who have psoriasis have a family history of the disorder, and evidence suggests that inheritance may be autosomal dominant with incomplete penetrance. The disease has no sexual predilection and the onset is typically in adolescence. Although psoriasis may resolve spontaneously, it is often a lifelong process characterized by exacerbations and remissions.
Lesions are typically pruritic and pink. Erythematous, circumscribed, differentiated lesions (plaques) that are covered with a silvery adherent scale may appear on the body surface. Lesions often coalesce to form larger plaques. An area of paler skin may surround the plaques. If the scale is scratched or removed, pinpoint bleeding may occur, which is called the Auspitz sign, which is not pathognomonic because it may also be observed in seborrheic and actinic keratoses. The disease also exhibits Köbner phenomenon, ie, the development of lesions secondary to mild trauma.
Several variations of psoriasis exist, including guttate, pustular, exfoliative erythrodermic, and inverse. Psoriasis may affect any part of the body, but the knees, elbows, scalp, anogenital region, and nails are most commonly affected. Eighteen percent of patients, especially those with extensive scalp involvement, have external ear involvement at some time during their lives. The periauricular skin, conchae, and external auditory meatus are the regions of the ear most likely to be affected. Ear involvement may be intensely pruritic, and the scaly lesions may accumulate in the external auditory canal, which results in diminished hearing. The ear is affected more often in women, and nearly 50% of ear involvement occurs in individuals aged 10-29 years.
In addition to the classic skin lesions, psoriasis may also manifest as nail and joint involvement. Up to 30% of patients may present with thickening of distal nail plates, separation and pitting of nails, and a white or yellow opacification, commonly referred to as oil spots. Finally, approximately 5% of patients have joint involvement.
Diagnosis is generally made with the help of a history and physical examination. Laboratory examinations usually do not provide any additional information. Occasionally, skin biopsy may be performed. Histologically, psoriasis is characterized by hyperkeratosis, parakeratosis, neutrophilic microabscesses, acanthosis, thinning of the suprapapillary plate, and dilation of superficial dermal vessels with a perivascular infiltration of lymphocytes.
Differential diagnoses include excoriated neurodermatitis, seborrheic dermatitis, and onychomycosis. Although psoriasis and seborrheic dermatitis are often similar in appearance, seborrheic dermatitis is characterized by diffuse, scruffy, greasy-appearing scales and is usually less erythematous than psoriasis. In addition, psoriasis is less likely to affect the face.
Treatment involves high-potency topical corticosteroids with or without occlusion, topical calcipotriene with or without occlusion, a combination of crude coal tar and UV therapy (Goeckerman regimen), topical anthralin, UV therapy with oral psoralens, or topical retinoids. In severe cases, systemic therapy with methotrexate, hydroxyurea, aromatic retinoids such as etretinate, and sulfasalazine (Azulfidine) may be of temporary benefit. Although systemic corticosteroids may be temporarily beneficial, avoid these agents because they aggravate the condition upon withdrawal. Improvements have been reported in diabetic patients who received thiazolidinedione rosiglitazone, including one patient who had complete resolution of plaques over her entire body and ears.  However, a recent large-scale, randomized, double-blind, placebo-controlled study showed no benefit from rosiglitazone over placebo. 
Relapsing polychondritis is an autoimmune disorder in which an individual exhibits a cell-mediated immune response to cartilage proteoglycans and produces antibodies to cartilage matrix and native and denatured type II collagen. Mean age of onset is in the fifth decade of life, and no sexual or racial predilection exists. Although no clear etiology has been identified, a hormonal precipitating factor has been postulated.
Systemic destruction of articular and nonarticular cartilage characterizes the disease, which commonly affects the head and neck (eg, eyes, ears, eustachian tube, nose), respiratory system (eg, larynx, trachea, bronchi), cardiovascular system (eg, heart valves, blood vessels), and joints. Table 1 lists the more common manifestations of relapsing polychondritis and their incidences.
The external ear is affected in up to 88% of cases. Relapsing polychondritis usually manifests as cellulitis of one or both pinna. Because cartilage is lacking, the earlobes are typically spared. Destruction of external auditory canal cartilage may result in conductive hearing loss, while disruption of inner ear anatomy may result in sensorineural hearing loss, vertigo, or tinnitus.
|Organ System||Manifestation||Incidence, %||Additional Information|
Hearing loss (sensorineural or conductive), tinnitus, vertigo
|Presenting sign in 26% of cases|
|Joints||Arthritis/arthropathy||81||Presenting sign in 23% of cases|
|Nose||Saddle nose, septal swelling||72||Presenting sign in 13% of cases|
|Eye||Episcleritis, iritis, conjunctivitis, keratitis||65||
|Larynx||Stridor, choking sensation, laryngeal tenderness||55||
|Cardiovascular system||Valvular disease, aneurysms, vasculitis, thrombitis||23||
Derived from Lucente FE, Lawson W, Novick NL: The External Ear. Philadelphia, Pa: W.B. Saunders Co; 1995.
After articular chondritis, arthropathy is the second most common manifestation of relapsing polychondritis. The arthropathy is nonselective and affects both small and large joints with equal frequency. This condition is also typically migratory, asymmetric, and seronegative. Occasionally, a positive rheumatoid factor (RF) is noted. However, this result may be secondary to a concomitant diagnosis of rheumatoid arthritis.
Almost a fourth of individuals diagnosed with relapsing polychondritis develop a second autoimmune disorder. Associated diseases include rheumatoid arthritis, systemic lupus erythematosus, myasthenia gravis, Hashimoto thyroiditis, pernicious anemia, Sjögren syndrome, and ulcerative colitis.
Laboratory abnormalities that may support the diagnosis include mild anemia and an elevated erythrocyte sedimentation rate. In the early stages of the disease, 30-60% of patients have detectable levels of antibodies to type II collagen. Additional tests, such as a serum B-12 level, thyroglobulin and microsomal antibodies, RF, antinuclear antibody (ANA), and acetylcholine receptor antibodies, may be obtained based on clinical suspicion for associated diseases.
Diagnosis is generally clinical, although lab tests may be helpful. Diagnosis requires that 3 of the following symptoms or signs be present:
Nonerosive seronegative inflammatory polyarthritis
The definitive test to help make the diagnosis of relapsing polychondritis is biopsy of the affected ear. Deep biopsies that include cartilage are essential to the diagnosis because the cartilage is the affected tissue. Staining with hematoxylin and eosin results in a distinctly pink color to the cartilage. Normal cartilage stains blue with hematoxylin and eosion (H and E) staining. Early in the disease process, the most common histologic finding is a neutrophilic infiltration. As the disease progresses, histologic findings include infiltration of the cartilage and perichondrial tissues with neutrophils, eosinophils, and lymphocytes, loss of cartilaginous matrix, and, ultimately, fibrosis.
Immunofluorescence studies of the tissue have demonstrated immunoglobulin C3–complex deposition at the chondrofibrous junction in 2 patients. Treatment consists of systemic corticosteroids, NSAIDs, or colchicine. Other treatments that have been tried with success include dapsone, methotrexate, cyclosporine, cyclophosphamide, azathioprine, and mycophenolate mofetil.
Table 2. Differential Diagnoses of Common External Ear Inflammatory Conditions (Open Table in a new window)
|Disease||Etiology and Epidemiology||Lesion Description||Differential Diagnoses|
|Atopic dermatitis||Systemic disorder commonly seen in families with history of asthma, allergic rhinitis, or other atopic disorders||
Erythematous scaly crusts, fluid-filled lesions, or both
Postauricular fissures may be present
|Allergic contact dermatitis||Delayed-type hypersensitivity when a previously sensitized individual comes in contact with an allergen||
Erythematous, edematous, and pruritic
Acute: Circumscribed solid skin elevations, weeping fluid-filled lesions, exudation and crusting may be present
Chronic: Thickening of skin from scratching
Fissuring may be present
Irritant contact dermatitis
Infectious eczematoid dermatitis
Discoid lupus erythematosus
|Photoallergic dermatitis||Delayed-type hypersensitivity that occurs when an ingested substance reacts with sunlight that results in dermatitis||Variable lesions: hives (urticaria); solid, erythematous, circumscribed, raised skin lesions (papules); small (< 0.5 cm) fluid-filled lesions (vesicles); blisterlike lesions; lesions may be pruritic||
|Relapsing polychondritis||Autoimmune disorder in which antibodies to cartilage matrix and type II collagen are produced||
Destruction of articular and nonarticular structures throughout the body
Cellulitis of the ear
Erythema, pain, swelling, and discoloration of pinna
Cellulitis of the pinna
Overexposure to sunlight and extreme cold
Autoimmune disorders such as lupus
Irritant contact dermatitis
Irritant contact dermatitis is a dose-dependent reaction to chemicals commonly found in soaps, turpentine, household detergents, solvents, cleaners, and strong alkali and acidic compounds. These chemicals have a direct toxic effect on the skin. Chemicals found in soaps, shampoos, and jewelry cleaners more commonly affect the ears.
History and examination of the lesions are the main diagnostic tools. As in allergic contact dermatitis, erythema and edema, small (< 0.5 cm) fluid-filled lesions (vesicles), and larger blisterlike lesions (bullae) typically characterize irritant contact dermatitis. Lesions are histologically indistinguishable from allergic contact dermatitis. During assessment of the lesions, remember that irritant contact dermatitis is 5 times more common than allergic contact dermatitis. In rare instances, patch testing may assist in making the diagnosis. Patch testing involves placing patches of common irritants on the skin and observing the subsequent reaction. However, a patch test has limitations. Most importantly, test exposure may be less than the actual clinical exposure and, therefore, may fail to elicit the same response.
Differential diagnoses include allergic contact dermatitis, seborrheic dermatitis, atopic dermatitis, and sunburn. Treatment involves avoidance of the offending agent. In severe cases, cool compresses and topical corticosteroids may be used to relieve symptoms.
Phototoxic dermatitis, also known as berloque dermatitis, is a nonimmunologic dermatitis that commonly affects the face, neck, upper chest, hands, forearms, legs, and other sun-exposed skin. Like photoallergic dermatitis, this condition results from a combination of ingested or topical agents and sunlight. Unlike photoallergy, however, the agents do not haptenate with skin proteins. Rather, the agents are usually polycyclic compounds that absorb UV-A radiation.
Phototoxic dermatitis is more common than photoallergy and often results from ingestion of psoralens or furocoumarins found in plants and fruits (eg, limes, parsley, celery, figs) and drugs such as thiazides, tetracycline, sulfonamides, griseofulvin, phenothiazines, chlorothiazides, nalidixic acid, coal tar, and sulfonylureas. Psoralens are most commonly implicated in ear involvement. In mice, topical quinolones have resulted in edema when the ear is exposed to sunlight.
Lesions are streaks of erythema and may resolve with postinflammatory hyperpigmentation of the affected regions. As in photoallergic dermatitis, history and physical examination are usually the main diagnostic tools. Patch testing may also be of assistance.
Treatment involves avoidance of the offending agent and of sunlight. If sun exposure is inevitable, instruct the patient to use protective clothing, a hat, and sunscreen to provide maximum protection. Relief of symptoms may be provided with cool compresses and topical corticosteroids.
Erythema and edema of the skin following exposure to the sun or other sources of UV light (eg, tanning beds) are characteristics of phototrauma, which is more commonly referred to as sunburn. Solar UV light, mostly UV-B and UV-C, is absorbed by the epidermis. By contrast, UV-A, which is 5 times more concentrated in tanning beds than in sunlight, penetrates the dermis. All 3 forms of UV light may damage the skin. Maximum UV exposure occurs between 11:00 am and 3:00 pm and, contrary to popular belief, occurs even on cloudy days. In fact, UV light exposure is reduced by only 20-40% on a cloudy day.
Phototrauma most commonly affects fair-skinned individuals with blond or red hair. A combination of factors, including skin type and length and intensity of sun exposure, affect the degree of damage from sunburn. Lesions may range from mild erythema and edema of the skin to blisterlike lesions (bullae), crusting, and even ulcerations. The skin may be pruritic or tense and painful. The ears are commonly affected because of their position on the head. In addition, they are often overlooked during the application of sunscreen.
Pathophysiologically, UV radiation damages cell membranes and DNA and transiently disturbs protein synthesis. The damage results in elaboration of cytokines and other inflammatory mediators.
Only history and physical examination are needed to help make the diagnosis. However, most patients with sunburn never present to a physician. Therefore, education about prevention is imperative. Many resources regarding sun protection are available, including an instructional course for children. Studies have shown that education is an effective intervention for phototrauma.
Prevention includes use of hats, sunscreens, and protective clothing. Sunscreens are assigned sun protection factor (SPF) ratings. SPF, according to Diffey, is defined as the ratio of the least amount of UV energy required to produce a minimal erythema on skin that is protected by sunscreen to the amount of energy required to produce the same erythema on unprotected skin. Because most individuals apply less sunscreen than required to achieve the SPF, a discussion with the patient about the meaning of SPF is important. Treatment of phototrauma is based on symptoms and includes cool compresses. In severe cases, systemic corticosteroids may be used.
Chondrodermatitis nodularis helicis
Chondrodermatitis nodularis helicis, also known as Winkler disease, is a disease characterized by a small tender nodule on the helix that develops as a result of mechanical or environmental (sun exposure) trauma. Mechanical pressure against the ear may be a result of sleeping on the affected side, excessive telephone or earphone use, and wearing tight headgear. Both men and women are susceptible. Although these lesions generally develop unilaterally and more often on the right side, bilateral lesions have been reported.
Lesions are generally found on the superior portion of the helix in middle-aged and older men and on the lateral rim of the helix and antihelix in women. The lesions may also be noted on the tragus, antitragus, and concha. One report saw an increase in the incidence of such lesions on the antihelix and tragus as a result of an increase in cellular phone usage.  To date, one report of a lesion on the posterior aspect of the pinna exists, the result of an unusual sleep position, which further supports mechanical pressure as the etiologic agent.  All of these regions of the ear lack the protective benefit of subcutaneous tissue and generally have poor vascular supply.
The characteristic round-to-oval nodules are tender and are usually covered with a scale or crust. Removal of the crust reveals a channel through which necrobiotic substance (ie, degenerated connective tissue) is extruded from the dermis. The lesion may also be ulcerated. It rarely grows larger than 3 mm to 1.5 cm. The primary symptom of patients is pain and tenderness upon manipulation of the lesion.
Differential diagnoses include basal cell carcinoma, squamous cell carcinoma, and premalignant keratoses. To exclude these diagnoses, a biopsy of the lesion may be performed. Histologically, the lesion is a central necrotic area surrounded by a rim of hyperkeratotic and parakeratotic tissue of varying degrees. Hypervascularity from multiple small vessels between the cartilage and the lesion has been noted. In addition, in some cases, a large nerve fiber or multiple small nerve fibers have been noted within the lesion, potentially explaining its painful nature.
Treatment consists of modification of the instigating event (eg, less telephone usage, wearing less constricting headgear) and avoidance of pressure on the affected ear. Other treatment modalities include intralesional corticosteroid injections, topical steroids, cryotherapy, curettage, electrocauterization, intralesional collagen injections, pentoxifylline, and CO2 or argon laser therapy.
Successful treatment of chondrodermatitis nodularis helicis with topical nitroglycerin, in gel or patch form, has been reported. In a prospective study of 11 patients with the disease who were treated with nitroglycerin patches (5 mg; 12 hours per day for 2 months), Garrido Colmenero et al found that 7 patients (63.6%) had a complete response to the therapy. [9, 10]
Surgical excision is another treatment. For larger lesions, a wedge excision of the pinna with a pedicled flap reconstruction, such as the Antia-Buch procedure, may be used.
Currently used in the treatment of malignancies, radiation therapy was once used in the treatment of such benign conditions as acne, hirsutism, eczema, and ringworm. Iatrogenic exposure, whether in the form of x-rays or radiation therapy with cobalt or radium, potentially has many harmful side effects. The external ear, like any other body part, is susceptible to radiation damage. Damage may manifest as radiodermatitis, chondritis, perichondritis, chondronecrosis or osteoradionecrosis (ORN). In addition, some patients may present with a conductive hearing loss secondary to tragal retraction over the external auditory canal or secondary to external auditory canal stenosis.
The ear is commonly affected when it lies in the radiation-treatment field of parotid tumors or of nasopharyngeal carcinoma. External ear injury may also occur following treatment of cutaneous cancers of the pinna and brain malignancies.
Radiodermatitis of the ear can be divided into 2 stages, namely, acute and chronic.
Acute radiodermatitis has a latency period of 6-12 days, and its characteristics are as follows: 
- Erythema followed by spotty hyperpigmentation
- Transient alopecia
- Permanent loss of appendages
- Primary deep tissue necrosis
- Acute painful ulcerations
Chronic radiodermatitis has a latency period of 2 years to decades, and its characteristics are as follows: 
In the acute stage, the ear is erythematous and edematous and the patient typically presents with a raised solid (papular) eruption similar to erythema multiforme. However, the patient may also present with a pruritic hivelike (urticarial) eruption, a thickened skin (lichenoid) eruption, a blisterlike lesion (bullae), or bruise (purpura) on the ear. In rare cases, an exfoliative process with fever and arthralgias may be observed. Other types of dermatitis that may present subsequent to radiotherapy include pemphigus dermatitis, bullous pemphigoid, and morphea. The acute stage generally begins 6-12 days after initial therapy; however, latent periods as long as 3 weeks have been noted.
The chronic stage of radiodermatitis may present as poikiloderma, ulcers, keratoses, carcinoma, or a combination of these conditions. Dry atrophic skin with telangiectasias, mottled hyperpigmentation and hypopigmentation, and loss of appendages characterizes poikiloderma. Sharply defined central ulcers are covered with a necrotic, greasy, yellow eschar. Radiation-related ulcers may also be observed. These ulcers do not heal well. In 20% of patients, a hard infiltrate surrounds the ulcers. This infiltrate is carcinogenic and is referred to as roentgen carcinoma.
Late complications of radiation that affect the external ear are ORN and chondroradionecrosis. Clinically, ORN may manifest as an otitis externa refractory to antibiotic therapy. It often develops months to years following the completion of radiation.
Finally, radiation-related keratoses are precancerous tumors that resemble actinic keratoses. Features of chronic radiodermatitis usually follow second- and third-degree acute radiodermatitis and may not be apparent for years following therapy. Occasionally, deep radiation may sensitize the skin, triggering an acute radiodermatitis upon subsequent x-ray exposure. This phenomenon is rare and occurs only once in every 5000 patients who receive deep radiation.
History and physical examination are the main diagnostic tools. Atrophy of the epidermis, hyalinized and irregularly stained collagen, and telangiectasia of dermal vessels histologically characterize chronic radiodermatitis. In addition, atypical dendritic cells that express antibodies to factor XIIIa are observed in the dermis.
In addition to conductive hearing loss, sensorineural hearing loss is also often seen as a side effect of radiation to the nasopharynx or parotid. The loss may be related to the effects of radiation on the cochlea rather than retrocochlear pathways.
Treatment in the acute stage consists of emollients. In the case of secondary infection, immediately initiate appropriate antibiotic therapy and debride devitalized tissue as necessary. Treatment of ORN or chondroradionecrosis includes systemic antibiotics, debridement of devitalized tissues (including mastoidectomy if temporal bone is involved), and adjunctive hyperbaric oxygen treatment.