Hyperkeratotic flexural erythema (more commonly known as granular parakeratosis) with use of laundry sanitizers containing benzalkonium chloride.

BACKGROUND: Hyperkeratotic flexural erythema (HKFE), also known as granular parakeratosis, is a scaly, erythematous or brown eruption, which usually occurs in the intertriginous and flexural areas. It has been linked to the use of benzalkonium chloride (BAK). AIM: To review the clinical presentation of patients diagnosed with HKFE who had been exposed to laundry sanitizer containing BAK, and the therapies trialled to treat these patients. METHODS: This was a retrospective cases series of 45 patients seen by dermatologists in Victoria, Australia. Information was collected on clinical presentation, investigation and management. RESULTS: The patients varied in age from 18 months to 89 years. The rash typically presented as a symmetrical erythema with characteristic multilayered brownish epidermal scaling. The most common location of the rash was the inguinal/anogenital area (32 of 45 patients; 71.1%) and there was a female predominance. Regarding treatment, topical corticosteroids were frequently prescribed and antibiotics were trialled in 11 patients; however, the condition resolved spontaneously over time in all patients with use of emollients, along with cleaning of the washing machine by running an empty wash, and repeated washing or sometimes disposal of BAK-contaminated clothing. CONCLUSION: This large case series highlighted the characteristic clinical presentation of HKFE in the setting of BAK used in laundry sanitizer, demonstrating a potential causal link. Further studies are required to evaluate the role of the skin microbiome.

Keratoacanthoma formation after skin grafting: A brief report and pathophysiological hypothesis.

Keratoacanthoma formation after skin grafting is rare. We report the third case in the literature of multiple keratoacanthomas developed at both split-thickness skin graft donor and recipient sites. We provide possible explanations for this poorly understood phenomenon and highlight its implications on treatment options.

Nicotine replacement therapy as a treatment for complex aphthosis.

Complex aphthosis, the occurrence of recurrent oral and genital aphthous ulceration without manifestations of systemic disease, is relatively uncommon and of unknown aetiology. We describe a case of complex aphthosis which began within weeks of stopping smoking. After failing to respond to conventional agents, the patient was successfully treated with nicotine lozenges. Recurrent aphthous stomatitis (RAS) is known to be less common in smokers and there have been previous reports of nicotine being used as successful treatments for RAS and Behçet's disease. We discuss the mechanisms of action of nicotine whereby nicotine could influence the natural history of aphthous ulceration. We recommend considering its use when conventional management has failed, particularly in ex-smokers.