Faculty Bibliography

The diagnosis of dermatologic conditions typically hinges on the examination of visibly apparent skin abnormalities. On occasion, dermatologists can aid in diagnosing the "invisible" by performing biopsies of skin that seems clinically normal, with the hope that histologic clues only apparent in tissue samples-and not by the naked eye-may yield helpful diagnostic information. This narrative review discusses the utility of random, normal skin biopsy in the diagnosis of a variety of conditions for which this method has been described. Herein, we review the available literature on the use of normal skin biopsy for Alport syndrome, amyloidosis, atypical hemolytic uremic syndrome; cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy, intravascular lymphoma, lysosomal storage disorders, pseudoxanthoma elasticum, rabies, and small fiber neuropathies.

This case describes a 50-year-old kidney transplant recipient with subacute development of erythematous-to-violaceous skin lesions on the face, trunk, and extremities, accompanied by malaise, myalgia, and arthralgia. Histopathologic analysis of skin biopsies revealed characteristic vascular proliferation consistent with bacillary angiomatosis (BA), a rare angioproliferative disease caused by Bartonella henselae or Bartonella quintana infection, primarily affecting immunocompromised individuals. The patient was treated successfully with oral doxycycline, resulting in the resolution of symptoms and lesions. BA is typically transmitted via cats and presents variably, including cutaneous angioproliferative lesions, hepatic or splenic involvement, and endocarditis. Diagnosis relies on histopathology with specialized staining and molecular testing, as culture and serologies are often insufficient. Treatment typically involves prolonged antibiotic therapy, emphasizing the importance of early recognition in immunosuppressed patients, including solid organ transplant recipients, to prevent complications.

Acne is a common skin condition, but little data exist on the comparative efficacy of topical acne therapies. We conducted a systematic review and network meta-analysis to evaluate the efficacy of topical therapies for mild-to-moderate acne. Searches in PubMed/MEDLINE, Cochrane CENTRAL via Ovid, Embase via Ovid and Web of Science were conducted on 29 November 2021. Randomized controlled trials examining ≥12 weeks of topical treatments for acne vulgaris in subjects aged 12 and older were included. Main outcomes were absolute or percent change in acne lesion count and treatment success on the Investigator's Global Assessment scale. Thirty-five randomized clinical trials with 33,472 participants comparing nine different topical agents were included. Adapalene-benzoyl peroxide (BPO), clindamycin-BPO and clindamycin-tretinoin demonstrated the greatest reduction in non-inflammatory (ratio of means [RoM] 1.76; 95% CI [1.46; 2.12], RoM 1.70; 95% CI [1.44; 2.02] and RoM 1.87; 95% CI [1.53; 2.30], respectively), inflammatory (RoM 1.56; 95% CI [1.44; 1.70], RoM 1.49; 95% CI [1.39; 1.60] and RoM 1.48; 95% CI [1.36; 1.61], respectively) and total lesion count (ROM 1.67; 95% CI [1.47; 1.90], RoM 1.59; 95% CI [1.42; 1.79] and RoM 1.64; 95% CI [1.42; 1.89], respectively) compared to placebo. All single agents outperformed placebo except tazarotene, which did not significantly outperform placebo for inflammatory and non-inflammatory lesion count reduction. Most combination agents significantly outperformed their individual components in lesion count reduction and global assessment scores, except for clindamycin-tretinoin and clindamycin-BPO, which did not significantly outperform tretinoin (RoM 1.13; 95% CI [0.94; 1.36]) and BPO (RoM = 1.15, 95% CI [0.98; 1.36]), respectively, for non-inflammatory lesion reduction. There was no significant difference amongst most single agents when evaluating lesion count reduction. Combination agents are generally most effective for mild-to-moderate acne; however for non-inflammatory acne, the addition of clindamycin in topical regimens is unnecessary and should be avoided.

Cutaneous lupus erythematosus (CLE) is an autoimmune disease with diverse clinical manifestations, including patchy hair loss resembling alopecia areata (AA). This report describes two cases of CLE presenting as AA mimickers, emphasizing the need to consider CLE in differential diagnosis for patchy hair loss. Early and accurate diagnosis is crucial for effective management and preventing scarring alopecia. J Drugs Dermatol. 2025;24(3):324-326. doi:10.36849/JDD.7793R1.

Contact dermatitis (allergic and irritant) occurs when the skin encounters haptens that elicit a T cell-mediated hypersensitivity reaction (allergic) or a nonimmunologic, toxic reaction (irritant). Patch testing is the reference standard for diagnosing allergic contact dermatitis (ACD), although positive results are not always relevant. Therefore, the definitive diagnosis of ACD requires an astute clinician able to connect the results of patch testing appropriately with the clinical history and the cutaneous examination findings. Comorbid conditions such as atopic dermatitis can confound the accurate diagnosis of ACD because of the similarities in clinical presentation. Furthermore, both extremes of age can further challenge the diagnostic specificity of ACD owing to the maturing immune system and the space limitations present when the very young are patch tested. The goal of this Continuing Medical Education article is to discuss the challenges of diagnosing ACD in patients with unique comorbidities such as atopic dermatitis, given the morphologic similarities, and when to patch test these patients. Diagnosis of ACD will also be discussed in very young patients with a focus on patch test allergen selection despite the limited geographic space. The most common allergens reported in very young and old patients will also be discussed.