Transient Reactive Papulotranslucent Acrokeratoderma: A Report of 3 Cases Showing Excellent Response to Topical Calcipotriene
Transient reactive papulotransucent acrokeratoderma (TRPA) is a rare disorder characterized by edema and wrinkling of the palms following 5 to 10 minutes of contact with water that typically resolves within 1 hour after cessation of exposure. Based on encouraging preliminary observations in 3 patients, the authors recommend therapeutic trials of topical calcipotriene in the treatment of TRPA.
Originally, it was proposed that TRPA is a variant of punctate keratoderma or hereditary papulotranslucent acrokeratoderma.2,3 However, its position within the keratoderma spectrum is unclear and the etiopathogenesis has not been fully elucidated. Some investigators believe that transient structural and functional alterations in the epidermal milieu prompt epidermal swelling and compensatory dilation of eccrine ducts.3,4,7,8,10 Other reports implicate the inherent structural weakness of eccrine duct walls3,4,11 or aberrations in eccrine glands.5,12 Whether the fundamental pathology lies within the epidermis, eccrine ducts, or the eccrine glands remains to be determined. Nevertheless, reports of TRPA in the setting of cystic fibrosis and its carrier state3,11 as well as the presence of hyperhidrosis in most affected patients and the accumulation of lesions along the palmar creases may implicate oversaturation of the epidermis (due to salt retention or abnormal water absorption by the stratum corneum) as the pivotal event in TRPA pathogenesis.1,10 Once the disease is expressed in susceptible individuals, episodes might be provoked by external factors such as friction, occlusion, sweating, liquid cleansers, antiseptic gels, gloves, topical preparations, and oral medications (eg, salicylic acid, cyclooxygenase 2 inhibitors).1,4
Treatment alternatives such as hydrophilic petrolatum and glycerin, ammonium lactate, salicylic acid (with or without urea), aluminum chloride hexahydrate, and topical corticosteroids are limited by unsuccessful or temporary outcomes.1,4,6,8-10 Botulinum toxin injections were effective in a patient with TRPA associated with hyperhidrosis.7 In the cases reported here, topical calcipotriene accomplished dramatic clearance of the lesions within the initial weeks of therapy. Spontaneous resolution was unlikely in these cases, as conservative therapies had not alleviated the signs and symptoms in any of the patients. However, we cannot exclude the possibility that improvement of the skin barrier function associated with other ingredients in the calcipotriene ointment (eg, petrolatum, mineral oil, α-tocopherol) may have led to the resolution of the lesions.
Calcipotriene has demonstrated efficacy in treating cutaneous disorders characterized by epidermal hyperproliferation and impaired terminal differentiation. Immunohistochemical and molecular biological evidence has indicated that topical calcipotriene exerts more pronounced inhibitory effects on epidermal proliferation than on dermal inflammation. It has been proposed that the bioavailability of calcipotriene in the dermal compartment may be markedly reduced compared to its availability in the epidermal compartment13; therefore it can be deduced that its penetration into the dermis is low in the thick skin of palms and its effect on eccrine sweat glands is negligible. Based on these factors, the clinical benefit of calcipotriene in TRPA could be ascribed directly to its antiproliferative and prodifferentiating effects on epidermal keratinocytes. We believe the primary pathology of TRPA lies in the epidermis and that changes in eccrine ducts and glands are secondary to the epidermal changes.
It is difficult to conduct large-scale studies of TRPA due to its rare presentation. Based on our encouraging preliminary observations in 3 patients, we recommend further therapeutic trials of topical calcipotriene in the treatment of TRPA.
