Practice Essentials
First described by Kyrle in 1916, Kyrle disease is a perforating skin condition characterized by the presence of large keratotic papules distributed widely throughout the body. The papules contain a central keratotic plug, which histologically correlates with keratin and necrotic debris. The disease is most closely associated with diabetes mellitus and renal failure. The condition was first identified in a diabetic patient. [1]
Causes
Debate about the precise pathophysiology of the disease exists. Some cases appear to be idiopathic or inherited, but other examples of Kyrle disease are associated with systemic disorders. A case report by Kasiakou et al [2] noted regression of lesions following antimicrobial therapy, suggesting a role for bacterial infection in pathogenesis. The following list includes several of the associated systemic disorders:
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Diabetes mellitus [3]
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Hepatic abnormalities (primary sclerosing cholangitis, [4] alcoholic cirrhosis) [5]
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Congestive heart failure
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Renal disease - Chronic renal failure, albuminuria, elevated serum creatinine level, abnormal creatinine clearance, polyuria [6]
Prognosis
Improvement of skin lesions is possible. The ultimate prognosis depends upon the nature of any underlying systemic disease. Morbidity results from the appearance of the lesions and the intense itching that often is associated with the condition. However, significant morbidity and mortality may be more directly associated with the underlying disease (eg, diabetes mellitus, chronic renal failure, hepatic abnormalities).
Diagnostics
Examine blood glucose to evaluate for possible diabetes mellitus. Liver function studies are necessary in order to evaluate for possible underlying liver disease (eg, alcoholic cirrhosis). Perform renal function studies, including urinalysis, serum creatinine, and creatinine clearance, to evaluate for possible underlying renal disease.
On dermoscopy, lesions have been described as having a 3- or 4-zonal concentric pattern including a crust in the lesion's center that is enveloped by a keratotic scale. The other zones include a structureless whitish-gray area, a structureless pink area that includes dotted vessels, and a structureless brown area with a peripheral scale. These features correlate well with the histology. [7]
Surgical treatment
Carbon dioxide laser or cryosurgery may be helpful for limited lesions. Caution must be exercised for individuals with dark skin, especially with cryosurgery, because of resulting dyspigmentation. Also, lesions on the lower legs may heal poorly, particularly in patients with diabetes mellitus or poor circulation.
Consultations
Dermatologist or internal medicine specialist consultation may be necessary.
Pathophysiology
The pathophysiology of Kyrle disease is unclear. Some believe it is a variant of prurigo nodularis or may represent end-stage excoriations of a folliculitis on the legs in patients with renal failure.
The leading theory is that the disease represents transepidermal elimination of keratin and other cellular material. Carter and Constantine [8, 9] have suggested that in Kyrle disease keratinization focally occurs at the basilar layer of the epidermal, rather than normal proliferation with keratinization higher in the epidermis. This elicits a host inflammatory response, resulting in keratin, cellular material, and connective tissue being forced out of the skin through the epidermis. [10] Alteration of dermal connective tissue may also be an initiating step, causing an inflammatory response. Other skin diseases with altered connective tissue have a similar type of inflammatory response, such as elastosis perforans serpiginosa, and perforating collagenosis.
Some literature suggests that Kyrle disease may be a recessively inherited genodermatosis.
Epidemiology
In the United States and internationally, Kyrle disease is rare, except in the setting of chronic renal failure. In patients with chronic renal failure, perforating dermatoses (that are closely related to and probably represent variants of Kyrle disease) are more common. Kyrle disease occurs in 10% of dialysis patients. [11, 12]
Kyrle disease appears to be more common in African Americans, perhaps related to the high incidence of diabetes mellitus and renal failure in this population. This disorder may be more common in women. A wide age range exists among patients with Kyrle disease. The average age at time of presentation is 30 years.
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A typical lesion of Kyrle disease with central keratotic crater.
