Acrokeratoelastoidosis and Knuckle Pads Coexisting in a Child
Acrokeratoelastoidosis (AKE) is a marginal papular keratoderma that typically presents in childhood and young adulthood. Childhood cases have exhibited autosomal-dominant inheritance. Acrokeratoelastoidosis is distinct from other palmoplantar marginal papular keratodermas because of its characteristic dermal elastorrhexis with an overlying epithelial dell. We report an 11-year-old boy with multiple translucent hyperkeratotic papules in a linear fashion on the bilateral palmoplantar surfaces characteristic of AKE. He also presented with knuckle pads on the proximal and distal interphalangeal joints that rarely have been reported with AKE, suggesting that AKE and atraumatic knuckle pads may coexist.
Practice Points
- Acrokeratoelastoidosis presents as small, firm, translucent, linear papules on the ventral-dorsal palmoplantar junction.
- Acrokeratoelastoidosis does not require treatment but can be treated topically with keratolytics such as tretinoin and salicylic acid.
- Knuckle pads may respond to urea cream, salicylic acid cream, or intralesional corticosteroids.
Case Report
An 11-year-old boy presented with atraumatic thickening of the skin on the bilateral distal and proximal interphalangeal joints of 1 year’s duration. The patient also noted small bumps of unknown duration across the bilateral palms and soles with prominence on the lateral aspects. The patient previously used over-the-counter topical wart removal treatment and topical salicylic acid with minimal improvement. The patient reported no pertinent medical or surgical history, although there was a family history of Alport syndrome, predominantly in male relatives. The patient’s father and paternal grandfather were noted to have similar lesions on the palms.
On physical examination, multiple pink to flesh-colored hyperkeratotic plaques were noted over the proximal and distal interphalangeal joints of the bilateral hands (Figure 1A). Upon close inspection, there were small flesh-colored and slightly translucent papules in a linear distribution on the palmar surfaces of the hands (Figure 2A) with predominance on the thenar and hypothenar eminences. The flexural creases of the bilateral wrists also revealed linear flesh-colored papules. The same small flesh-colored and translucent papules also were noted on the plantar surfaces of the bilateral feet (Figure 2B).
,
A biopsy was obtained from one of the small translucent papules on the left palm. Hematoxylin and eosin–stained sections revealed elevated compact orthokeratosis with an underlying central epidermal dell (Figure 3). A diagnosis of marginal papular keratoderma was made and further elastin staining was completed. Elastin stains showed marked thinning of the elastin fibers throughout the reticular dermis. Many elastin fibers in the reticular dermis demonstrated a fine arborizing pattern that normally is only evident in the papillary dermis (Figure 4). Acrokeratoelastoidosis (AKE) was diagnosed histopathologically, and knuckle pads were diagnosed clinically.
Because the patient was asymptomatic, he did not want treatment of AKE. He had marked improvement of the knuckle pads after 1 month with daily application of urea cream 10% (Figure 1B), and intermittent use was required for maintenance.
