Kyrle Disease - Causes, Clinical Features, and Treatments

Introduction:

Kyrle disease is an uncommon papular (swelling) eruption of the skin of the lower limb and is highly associated with chronic systemic disorders such as diabetes (sugar) and kidney failure. Austrian pathologist and dermatologist Josef Kyrle first described this disease in a diabetic woman in 1916 and was originally named "hyperkeratosis follicularis et parafollicularis in cutem penetrams." It is characterized by transepidermal removal of keratin from the dermis (inner layer of the skin) onto the skin surface through the epidermis (outer layer of the skin). It is an acquired perforating dermatosis characterized by transepidermal (across or through the dermis) elimination of dermal components.

What Is Kyrle Disease?

It is a rare skin disorder. Kyrle's disease most frequently appears as several distinct, eruptive papules (bumps) with a central keratotic plug on the lower limb. Under the microscope, transepidermal (across or through the dermis) elimination of keratin is seen. In most cases, it appears secondary to chronic systemic illness, mainly renal failure, and diabetes.

What Causes Kyrle Disease?

The exact cause of this disease is not known. However, a few studies suggest certain reasons for the disease. They are as follows:

• Altered keratinization (the process by which skin cells mature and produce keratin protein) occurs in the epidermis's bottom layer (basal layer).

• Increased inflammatory response due to abnormal keratin (a protein present in hair, nails, and skin) in the epidermis.

• Keratin and other substances are expelled through the epidermis.

• The appearance of altered or defective connective tissue may be a risk factor for Kyrle's disease.

• Interleukin (IL)-31, a cytokine primarily produced from T cells (one of the white blood cells and forms a part of the body's defense system), is closely connected with itch provocation. It is expressed more frequently in chronic renal failure, which may lead to immune dysregulation and ultimately cause the disease.

What Are the Clinical Features of Kyrle Disease?

• Kyrle disease often manifests as red-brown nodules (elevated, solid, and palpable lesions) and hyperkeratotic bumps (thickening of the skin's outer layer, epidermis, made of keratin) with silvery scales and a central keratin plug.

• The lesions' size and shape may vary and measure about 1.5 cm (centimeter) in diameter.

• The lower limbs, particularly the calf, tibial region, and posterior aspect, are where skin lesions are most frequently found.

• The head, neck, and arms may also be affected. The palms and soles are rarely involved.

• There have also been reports of koebnerization, in which skin lesions develop in the areas of damage.

• Lesions may not be typically painful, but they can be itchy.

• Lesions may heal without any treatment, but new lesions keep developing.

Who Develops the Kyrle Disease?

Kyrle's disease affects adults between the age of 30 and 40. A female-to-male ratio of up to 6:1 is associated with a higher incidence in females. The two conditions that Kyrle disease is most frequently linked to are chronic renal disease and diabetes mellitus, especially in people who also have accompanied diabetic nephropathy - a condition where kidneys' ability to remove waste products and fluid is reduced. About 10 % of hemodialysis patients will eventually experience Kyrle's disease. It has occasionally been observed in endocrinological diseases, pulmonary aspergillosis (an infection developed by a fungus), scabies (an infection of the skin caused by a mite), atopic dermatitis (dry and itchy skin), AIDS (acquired immunodeficiency syndrome), neurodermatitis (skin disorder that causes continuous itching and scaling), malignancy (cancer), and tuberculosis (a bacterial infection which mainly affects the lung).

What Are the Complications of Kyrle Disease?

Quality of life is affected because of itching, which presents for a longer duration of time. Secondary bacterial and fungal infections by itching and damaged skin barrier. Healing of lesions produces scarring or dyspigmentation (abnormal distribution of pigments in the skin) of the skin.

How to Diagnose Kyrle Disease?

Based on characteristic clinical and histopathological (study of tissue changes caused by the disease under the microscope) findings, kyrle's disease is diagnosed. The histopathology report shows epidermal depression with a parakeratotic plug. Hair follicles may get involved. Debris may also be present in the plug. A blood glucose test is done to detect the presence of diabetes. To check for underlying liver and kidney disease, liver and kidney function tests are done. The biopsy is performed to study histopathological findings. A small piece of tissue from the lesion in a biopsy is removed and studied under a microscope to identify cell changes.

What Are the Differential Diagnoses of Kyrle Disease?

It is important to distinguish Kyrle's disease from other illnesses that result in papular or nodular eruptions with hyperkeratotic central plugs. They consist of the following:

• Multiple keratoacanthomas.

• Folliculitis.

• Arthropod hypersensitivity reaction.

• Dermatofibromas.

• Prurigo nodularis.

• Perforation of exogenous or endogenous foreign material.

More linearly distributed lesions should be considered in the differential diagnosis if koebnerization occurs. It includes psoriasis, lichen planus, and verrucae.

What Are Treatments Available for Kyrle Disease?

The main treatment goal is to reduce itching, which avoids superficial damage. Improvement is seen when the underlying systemic disease is managed.

• Keratolytics (breaks down the skin's outer layer and reduces scale thickness) such as salicylic acid and urea are first-line treatments.

• Topical creams include emollients, retinoids, steroids, and keratolytic agents.

• Systemic medications in the form of oral antibiotics and antihistamines such as Allopurinol.

• Alternative treatments include electrocautery, cryotherapy, CO2 laser (carbon dioxide laser), Isotretinoin, and Psoralen combined with ultraviolet A radiation.

• Oral Clindamycin 300 mg (milligram), three times daily for one month, is also effective in some cases.

• Skin lesions frequently recur after cessation of the treatments. Some reports say that after kidney transplantation in dialysis patients, there is an absolute regression in the disease.

• Surgical excision is used when it is severe and recurrent.

What Is the Outcome of the Disease?

The extent of underlying systemic disorders such as diabetes mellitus, chronic renal disease, and liver disease affects the outcome of Kyrle's disease. The development of lesions and severe itching are the causes of illness in Kyrle's disease. The underlying systemic illnesses are directly linked to the outcome of the disease.

How to Educate Patients With Kyrle Disease?

Patients with Kyrle disease should be educated about the nature of the disease and how to control and manage the underlying chronic systemic illness. Patients with diabetes are instructed to monitor their sugar levels strictly. Uremia (a rise in the level of urea and other nitrogenous compounds in the blood) should be properly treated for patients with kidney illness, as Kyrle disease typically goes away when uremia is managed. The patient should strictly follow the management of liver disease and heart failure.

Conclusion:

Kyrle disease is a rare skin condition with bumps containing keratin plugs and associated with systemic illnesses, mainly diabetes and kidney failure, commonly seen in lower limbs. Treatment mainly focuses on controlling systemic illness, which helps control the lesions, and topical treatments to control the itchiness. If symptoms resemble Kyrle disease, consult the doctor, identify the underlying systemic illness, and get treated accordingly.