Granular parakeratosis is a reaction pattern in hyperkeratotic flexural erythema

Abstract

3. The COVID-19 pandemic is likely to continue for many months before being downgraded to seasonal epidemic status. This means a patient may have their immunomodulator withheld for many months. SYSTEMIC CORTICOSTEROIDSDoses of predniso(lo)ne >20 mg/day are considered immunosuppressive, but sudden stopping, or significant reduction of dose, in patients on long-term systemic corticosteroids, is unwise, particularly if they have suddenly become physiologically stressed. Note that systemic corticosteroids are part of many adult respiratory distress syndrome (ARDS) protocols, but are not currently recommended for SARS-CoV-2, as there is weak evidence of harm when used in influenza-associated adult respiratory distress syndrome. REDUCING IMMUNOMODULATOR DOSEThe immunomodulating actions of conventional systemic agents are dose-related. Whilst there is no hard data to make firm recommendations, consider the following lower dosages.•Azathioprine: reduce to ≤0.5 mg/kg/day •'Biologics: no specific data available, but as their half-lives are considerable, they may better be modify on a case-bycase basis •Ciclosporin: reduce to ≤1 mg/kg/day. Some in vitro evidence of potential benefit in COVID-19 disease •Methotrexate: reduce to ≤10 mg/week •Mycophenolate mofetil: reduce to ≤1 gm/day (mycophenolic acid to ≤720 mg/day) •Retinoids: no need for dose adjustment •Systemic corticosteroids: reduce to ≤10 mg/day predniso (lo)ne equivalent.

Advice regarding COVID‐19 and use of immunomodulators, in patients with severe dermatological diseases

“…1 We would like to draw the attention of the authors to our recent publication on the same morphological entity where we proposed that granular parakeratosis should be considered a reaction pattern due to epidermal perturbation triggered by variety of causes. 2 In our experience, the clinical morphology described in the recently reported case by Shen S et al also occurs in people who have not used any benzalkonium chloride-containing laundry detergents, and some cases of hyperkeratotic flexural erythema do not show the histopathological features of granular parakeratosis at any given time. Therefore, we proposed the term hyperkeratotic flexural erythema (HKFE) to encompass all cases of this clinical entity.…”

“…As we reported previously, the skin lesions of hyperkeratotic flexural erythema rapidly improve within a few days, if a course of amoxicillin-clavulanic acid is given. 2 This we believe is due to an effect on the skin microbiome of the flexures. A comprehensive study of pathogenic as well as traditionally 'non-pathogenic' bacteria would be required to identify any putative causative organisms.…”

Clinical features, histology, and treatment outcomes of granular parakeratosis: a systematic review

“…This, combined with reported resolution observed following treatment with systemic antibiotics, has lent support to the role of an altered microbiome in the development of granular parakeratosis. 3,[14][15][16] However, rare reports of congenital onset, and development of granular parakeratosis following administration of systemic medications, highlight that the exact pathogenesis remains elusive and is a subject that warrants further investigation. [17][18][19] Notably, our review highlights that findings of parakeratosis and retention of keratohyalin granules within the stratum corneum, despite its name, is not always present on histologic examination of granular parakeratosis.…”

“…in 1991 as axillary granular parakeratosis and attributed to contact reaction to antiperspirants, it is currently conceptualized as a disorder of keratinization with an expanding list of postulated etiological factors and treatment options reported 1,2 . More recently, hyperkeratotic flexural erythema has been an alternative term proposed to recognize its heterogeneous clinical presentation and histologic features 3 …”

Symmetrical axillary lesions: a clinicopathological challenge

“…The use of antiperspirant is effective for hyperhidrosis, although certain chemicals may interfere with the keratinization process in the epidermis, and it may lead to a premature stop of the keratinization process and consequently failure of keratohyalin granules' degradation in the horny layer [1,[5][6].…”