What's new in dermatology

The following represent additions to UpToDate from the past six months that were considered by the editors and authors to be of particular interest. The most recent What's New entries are at the top of each subsection.

ATOPIC DERMATITIS AND OTHER DERMATITIS

Topical roflumilast for seborrheic dermatitis (January 2024)

Seborrheic dermatitis is a chronic, relapsing dermatitis involving areas rich in sebaceous glands (eg, scalp, face) that requires repeated or long-term maintenance treatment with topical anti-inflammatory agents. In a randomized trial that included 226 adults with moderate to severe seborrheic dermatitis, topical roflumilast, a potent phosphodiesterase-4 inhibitor with anti-inflammatory properties, was more effective than vehicle in achieving an Investigator Global Assessment score of clear/almost clear at eight weeks (74 versus 41 percent, respectively) [1]. Treatment was generally well tolerated. These findings contributed to approval by the US Food and Drug Administration of roflumilast 0.3% foam for the treatment of seborrheic dermatitis in adults and children older than nine years [2]. (See "Seborrheic dermatitis in adolescents and adults", section on 'Topical anti-inflammatory agents'.)

Investigational nemolizumab for prurigo nodularis (November 2023)

Treatment of prurigo nodularis (PN), a chronic skin disorder characterized by severe pruritus and multiple itchy nodules predominantly located on the extremities, is aimed at interrupting the itch-scratch cycle. In a phase 3, randomized trial that included 274 adults with moderate-to-severe PN, improvement in itch and skin appearance at 16 weeks, as measured by validated scoring systems, was greater for patients assigned to subcutaneous nemolizumab (an antagonist of interleukin-31, a cytokine linked to pruritus) than those assigned to placebo [3]. Adverse events in the nemolizumab group included exacerbation/new onset of atopic dermatitis and peripheral or facial edema. These findings, along with a prior small trial, indicate that nemolizumab has efficacy for the treatment of PN, although its use for this condition remains investigational. (See "Prurigo nodularis", section on 'Nemolizumab'.)

Dupilumab for prurigo nodularis (August 2023)

Prurigo nodularis (PN) is a chronic skin disorder characterized by severe pruritus and multiple itchy nodules predominantly located on the extremities. Treatment to date focuses on interrupting the itch-scratch cycle. In a phase 3 trial that included 151 adults with PN, more patients in the dupilumab group achieved a ≥4 point reduction in the Worst Itch Numeric Rating Scale at 24 weeks compared with placebo (60 versus 18 percent, respectively) [4]. Similar results were achieved as early as at 12 weeks in a second identical trial with 160 patients. In both trials, more patients in the dupilumab groups achieved an Investigator Global Assessment score of clear/almost clear at 24 weeks, compared with patients in the placebo groups. The safety profile of dupilumab was generally good. We suggest dupilumab for patients with widespread or recalcitrant PN who are candidates for systemic therapy. (See "Prurigo nodularis", section on 'Dupilumab'.)

Bacterial decolonization for the prevention of radiation dermatitis (August 2023)

It has been hypothesized that colonization with S. aureus may play a role in the development of severe radiation dermatitis. In a small randomized trial, 77 patients with breast or head and neck cancer undergoing radiation therapy received S. aureus decolonization (intranasal mupirocin 2% ointment twice daily and chlorhexidine gluconate 4% body cleanser once daily for five consecutive days every two weeks) or standard care (normal skin hygiene and emollients) [5]. None of the 39 patients treated with bacterial decolonization developed grade 2 or higher radiation dermatitis compared with 9 of 38 patients (24 percent) treated with standard of care. These findings suggest that bacterial decolonization may be a safe and easy intervention for the prevention of severe radiation dermatitis. However, larger confirmatory studies are needed before it can be routinely used in patients undergoing radiation therapy. (See "Radiation dermatitis", section on 'Bacterial decolonization'.)

SURGICAL AND COSMETIC DERMATOLOGY

Intraincisional clindamycin in skin cancer surgery (August 2023)

Intraincisional antibiotic prophylaxis using an extremely low dose of antibiotics has been shown to reduce the surgical site infection (SSI) rate in patients undergoing Mohs micrographic skin cancer excision. In a recent randomized trial that included 735 patients undergoing standard skin cancer surgery, intraincisional injection of local anesthetic plus clindamycin 500 mcg/mL was associated with a lower rate of SSI, compared with local anesthetic plus 500 mcg/mL flucloxacillin or local anesthetic alone (2.1, 5.3, and 5.7 percent, respectively) [6]. None of the patients received systemic preoperative prophylactic antibiotics. No adverse events were reported. These findings suggest that intraincisional microdoses of clindamycin may reduce the rate of SSI in skin cancer surgery and lend further support to avoiding use of preoperative systemic antibiotics in these patients. (See "Skin surgery: Prevention and treatment of complications", section on 'Intraincisional'.)

OTHER DERMATOLOGY

Risankizumab for dissecting cellulitis of the scalp (November 2023)

Oral antibiotics, oral isotretinoin, biologic tumor necrosis factor-alpha inhibitors, and surgical excision are the mainstays of treatment for dissecting cellulitis of the scalp (DCS), a debilitating form of scarring alopecia that can be challenging to treat. In a report of two patients with oral antibiotic-refractory DCS treated with risankizumab (a biologic interleukin [IL] 23 inhibitor), marked clinical improvement occurred within 4 to 13 months [7]. These findings add to other isolated reports suggesting benefit of biologic IL-23 inhibition for DCS. While promising, more evidence regarding safety and efficacy are needed. (See "Dissecting cellulitis of the scalp", section on 'Other therapies'.)

Memantine for trichotillomania and skin picking disorder (July 2023)

Skin picking (excoriation) disorder (SPD) and related conditions, such as trichotillomania, are separate diagnoses in the group of obsessive-compulsive and related disorders; successful treatment is challenging. Pharmacologic therapy (primarily selective serotonin reuptake inhibitor antidepressants or, for patients with features of delusional disorder, atypical antipsychotics) is suggested for patients who don’t accept or are not responsive to behavioral therapy but efficacy is unclear. Memantine, an oral glutamate modulator, was evaluated in a randomized trial that included 100 adults with trichotillomania, skin picking disorder, or both [8]. At eight weeks, memantine, compared with placebo, was associated with greater improvement from baseline in the modified National Institute of Mental Health Trichotillomania Symptom Severity Scale and in the Clinical Global Impressions severity scale. Treatment was generally well tolerated with adverse effects occurring with similar frequency in both groups. While encouraging, the efficacy and safety of memantine needs confirmation in larger and longer duration trials. (See "Skin picking (excoriation) disorder and related disorders", section on 'Memantine'.)