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Kyrle's disease (hyperkeratosis follicularis et parafollicularis in cutem penetrans)
A disorder of keratinization characterized keratotic papules on the extremities & trunk, most commonly associated with diabetes mellitus & renal failure, but also without associated disease.
Etiology:
1) associated disorders
a) diabetes mellitus & renal failure (most common)
b) hepatic insufficiency
c) congestive heart failure
d) hypothyroidism
e) hyperlipoproteinemia
2) idiopathic
Epidemiology:
1) uncommon
2) 3rd to 7th decade, rarely in infants & children
3) females > males
Pathology:
1) invaginating epidermal keratotic plug
- may perforate epidermal basement membrane into the dermis
2) focal parakeratotic & basophilic debris
3) marked thinning or perforation of the epidermis
4) neutrophil infiltrating in the dermis beneath keratotic plugs
5) lymphocyte & histiocyte dermal infiltrate around the lesions
Clinical manifestations:
1) insidious, asynchronous development of lesions
2) early lesions may be asymptomatic to slightly pruritic
3) older lesions may be painful, especially with applied pressure
4) traumatized lesions may become secondarily infected
5) initial lesion is small hyperkeratotic papule
6) lesions enlarge to form papules, nodules & plaques with hyperkeratotic caps/plugs
7) removal of the hyperkeratotic plug leaves a crater within a depressed nodule or papule
8) resolution of lesions generally leaves atrophic scars
9) larger lesions may become hyperpigmented
10) lesions are scattered or clustered
11) enlarging lesions may coalesce
12) distribution
a) extensor surface of extremities
b) trunk
c) buttocks
d) mucous membranes are not involved
Laboratory: skin biopsy
Differential diagnosis:
1) prurigo nodularis
2) multiple keratoacanthomas
3) perforating folliculitis
4) elastosis perforans serpiginosa
5) reactive perforating collagenosis
6) atypical mycobacterial infection
7) verruca vulgaris
Management:
1) topical agents
a) tretinoin gel or cream
b) keratolytic agents such as salicylic acid
2) oral etretinate
a) high dose
b) need for chronic administration precludes practicality
3) cryo-, electro- or CO2 laser surgery
a) resultant scar formation
b) may prevent recurrence of lesions at the treatment site
4) prognosis
a) chronic disorder
b) lesions may heal with atrophic scar
c) local recurrence is common
Related
hyperkeratosis
General
skin disease (dermatologic disorder, dermatopathy, dermatosis)
References
- Color Atlas & Synopsis of Clinical Dermatology, Common
& Serious Diseases, 3rd ed, Fitzpatrick et al, McGraw Hill, NY,
1997, pg 108-109
- Medical Knowledge Self Assessment Program (MKSAP) 18,
American College of Physicians, Philadelphia 2018