Hyperkeratotic flexural erythema responding to amoxicillin–clavulanic acid therapy: Report of four cases

Abstract

Hyperkeratotic eruptions in the flexures, especially in the inguinal region, often pose a diagnostic and therapeutic dilemma. Inguinal keratotic eruptions may be caused by various infections, inflammatory dermatoses, vesico-bullous dermatoses, nutrient deficiencies, medication allergies and other miscellaneous causes such as granular parakeratosis. We hereby report four patients who presented with idiopathic hyperkeratotic erythematous eruptions with a migratory nature involving the inguinal region and occasionally showing the histopathologic features of granular parakeratosis. All four patients showed a dramatic therapeutic response to amoxicillin-clavulanic acid combination. We suggest that 'granular parakeratosis' should be considered as a histopathologic feature rather than the diagnosis. We would prefer to label our cases as 'Hyperkeratotic Flexural Erythema'. We recommend that detailed study of skin microbiome may help identify a possible alteration in skin microbiome contributing to the pathogenesis. We briefly review strategies on characterising the skin microbiome and the latest knowledge surrounding how alterations to the skin microbial populations can contribute to some diseases.

Support for a Microbial Basis for Hyperkeratotic Flexural Erythema

“…Whilst the pathogenesis of hyperkeratotic flexural erythema is still yet to be completely defined, we agree with the authors 1 that it may have a microbial basis and we support their suggestion that anti‐microbial therapy is effective for this condition. Regarding the question of which microbe might be causally related we have noticed that this condition appears to spare skin folds which are typically exposed to sunlight and are well aerated, so this may suggest that a UV susceptible and moisture seeking microbe might be involved.…”

“…It was with interest we read the recent report by Kumarasinghe et al 1 which described a rapid response and enduring remission to amoxicillin–clavulanic acid therapy in four patients with hyperkeratotic flexural erythema. They suggested a microbial aetiology for this condition.…”

Granular Parakeratosis: A Case Report

“… 11 , 12 In addition, local dermatophyte infections, bacterial infections, and other reports related to GP have been published. 13 , 14 GP may also be a manifestation of other dermatological or systemic diseases such as GP combined with ichthyosis, atopic dermatitis, dermatomyositis myositis, or tumor-related GP. 7 , 8 , 15 , 16 Therefore, physical examination of the entire body cannot be ignored in the clinical evaluation of GP.…”

Hyperkeratotic flexural erythema/granular parakeratosis responding to doxycycline

“…HKFE/GP is a rare condition and there is no consensus on the management. Response to treatments such as topical steroids, antifungal preparations and antibiotics is unpredictable 4 . Similarly, calcipotriene, topical tretinoin and isotretinoin have been reported to yield optimal results only in some cases.…”

“…It presents as an intertriginous eruption with red-brown hyperkeratotic lesions, which can relapse over a period of time and cause considerable discomfort. [1][2][3][4] As described previously, considering 'granular parakeratosis' is only a histopathological description that is not found in all the cases, we use the clinical terminology hyperkeratotic flexural erythema (HKFE) in this article. 4 In HKFE, there is altered keratinocyte maturation from the stratum granulosum to the stratum corneum, where the main abnormality is the failure to process profilaggrin to filaggrin.…”