Erythrasma is a bacterial infection of the skin typically caused by Corynebacterium minutissimum. This pathogen infects the stratum corneum in warm and wet areas of the skin. Most commonly, the axillary, inguinal, and interdigital regions are affected. A 60-year-old man presented for the examination of a pedunculated lesion on his right proximal thigh. Upon examination of the lesion, adjacent areas of central hypopigmentation and peripheral hyperpigmented scaling were also noted bilaterally in the groin region. Differential diagnoses of candidiasis, dermatophyte infection, erythrasma, pityriasis versicolor, and terra firma-forme dermatosis were considered. Wood lamp examination revealed bright coral-pink fluorescence. Correlation of the clinical examination and the Wood lamp finding established the diagnosis of erythrasma. Twice daily topical 2% mupirocin ointment therapy led to the resolution of our patient’s erythrasma. In this case report, the diagnosis, differential diagnoses, and treatment of erythrasma are reviewed.

No abstract

Erythema ab igne is a thermal-associated skin condition that can occur secondary to persistent direct or indirect contact with heat. Historically, erythema ab igne has been linked to fireplace and stove exposures; more recently, it has been associated with heaters, hot water bottles, and laptops. A 48-year-old woman presented for the evaluation of hyperpigmented, reticulated macular lesions on her distal legs. Additional history revealed that she had developed erythema ab igne secondary to the use of a space heater underneath her desk at work. Her skin condition stopped progressing with removal of the causative agent. In addition to erythema ab igne, heatrelated skin conditions include basal cell carcinomas and squamous cell carcinomas, burns, erythromelalgia, subtypes of urticaria, and ultraviolet-associated disorders. Awareness of thermal-associated skin conditions enables the clinician to establish the appropriate diagnosis based on the associated history of the condition, the morphology of the skin lesion, and, if necessary, correlation with the skin biopsy findings of the cutaneous condition.

Basal cell carcinoma is the most common cutaneous neoplasm. Calcinosis cutis is the deposition of calcium within the dermis. An 80-year-old man presented with a pearly nodule on his left nasal ala; a shave biopsy confirmed the diagnosis of a nodular basal cell carcinoma with calcinosis cutis, which was removed with Mohs micrographic surgery. The incidence of basal cell carcinoma with calcinosis cutis as well as the classification, identification, and potential origin of calcium deposits in basal cell carcinoma are discussed. Basal cell carcinoma can be associated with calcinosis cutis; indeed, calcifying basal cell carcinoma has a calculated incidence of 14%. There are five categories of calcification in basal cell carcinoma. In addition, calcification observed in cancer-free initial sections of a suspected basal cell carcinoma may be a diagnostic clue that a neoplasm is present in deeper sections of the tissue specimen. Although nodular basal cell carcinoma has the greatest incidence (37%) of calcium deposition, infiltrative (29%) and micronodular (27%) basal cell carcinomas are also frequently associated with calcification; therefore, the presence of calcifying basal cell carcinoma may indicate a more aggressive tumor subtype. Basal cell carcinoma may also be suspected in the differential diagnosis of a superficial breast neoplasm in which calcification is observed in the dermis; in this situation, mammography has been an effective diagnostic approach for identifying the basal cell carcinoma with calcification. The pathogenesis of calcification in basal cell carcinoma remains to be definitively established; however, calcium-binding proteins found in poorly differentiated keratinocytes may contribute to the etiology of basal cell carcinoma with calcification. The treatment of basal cell carcinomas with calcinosis cutis is similar to that of non-calcifying basal cell carcinomas; it is based upon the histologic subtype, the size, and the location of the tumor.

Parrot beak nail dystrophy is an excessive forward curvature of the nail plate that can affect both fingernails and toenails. Few cases have been reported since its original description in 1971; however, the incidence is estimated to be 2.5% in healthy individuals. Although the pathogenesis has not yet been established, parrot beak nail has been associated with chronic crack cocaine use, congenital bone or soft tissue abnormalities, other nail dystrophies, peripheral neuropathy, systemic sclerosis, and trauma to the nail. We describe an 86year-old man with dementia and neuropathy who presented with an unperceived parrot beak nail of his left fourth toenail and concurrent onycholysis of his left great toenail. He had stopped visits with his podiatrist for nail care, which fostered the growth of these nail dystrophies. Our patient's parrot beak nail was successfully treated with nail clipping and regular nail maintenance to prevent its recurrence. The associated conditions, etiologies, and treatment of parrot beak nails are discussed.