Clindamycin is a lincosamide antibiotic that has been used as a topical, oral, or injectable formulation for over five decades. It exhibits a narrow spectrum of microbiologic activity, primarily against gram-positive and anaerobic bacteria. In dermatology, clindamycin has been used primarily as a topical agent, usually for the treatment of acne vulgaris. Despite questions surrounding antibiotic resistance and/or its relative contribution to antibiotic treatment efficacy, a large body of data support the therapeutic value of topical clindamycin for acne vulgaris. As a systemic agent, clindamycin is used orally to treat a variety of cutaneous bacterial infections, and sometimes for acne vulgaris, with oral treatment for the latter less common in more recent years. The modes of action of clindamycin are supported by data showing both its anti-inflammatory and antibiotic mechanisms, which are discussed here along with pharmacokinetic profiles and structure-activity relationships. The diverse applications of clindamycin for multiple disease states, its efficacy, and safety considerations are also reviewed here, including for both topical and systemic formulations. Emphasis is placed on uses in dermatology, but other information on clindamycin relevant to clinicians is also discussed.

Nonscarring scalp folliculitis (NSSF) has been poorly addressed in the literature. Previous studies have focused more on bacterial aetiology. Recent evidence has suggested an inflammatory hypothesis. Data on the role of Malassezia in NSSF are scarce. We retrospectively reviewed the hospital records of 26 NSSF patients diagnosed between September 2021 and October 2022. Malassezia spores were detected cytologically (May-Grünwald-Giemsa stain) in 96% of the patients. Fourteen patients underwent bacterial culture (no growth (4), coagulase-negative staphylococcus (9), and Staphylococcus aureus (1)). In total, 35% of patients had immunosuppression. Antifungal treatment reduced symptoms in 79% of the patients. Four patients received systemic isotretinoin. Recurrence was observed in 35% of patients. This case series suggests Malassezia should be recognized in the pathogenesis of NSSF, which should be confirmed by large-scale studies. Immunosuppression may serve as a predisposing factor in a subset of patients. Although antifungal treatment is efficient in most patients, frequent recurrences necessitate maintenance therapy.

Pseudofolliculitis barbae (PFB) is a chronic inflammatory skin disease favoured by shaving. It is particularly common among black Africans belonging to certain socio-professional categories who are obliged to shave. Its aesthetic and professional damage is very significant. However, very few data are available for this condition, especially in Sub-Saharan Africa.
To determine the epidemiological and clinical aspects, and the risk factors associated with the occurrence of PFB in Dakar.
This was a descriptive cross-sectional study conducted in March 2019, including 655 police students at the National Police Academy in Dakar, all of African descent and with curly hair, who were required to shave weekly and agreed to participate in this study. The diagnosis of PFB was clinically based. Data analysis was processed using Epi-info version 6.0 software. Pearson\'s chi-square test was used for bivariate analysis with a significance threshold of p < 0.05. The Odds Ratio, with its 95% confidence interval, was used to determine the risk factors.
Among the 655 officers, 254 had PFB, with a prevalence of 38.8%. The prevalence of PFB was 43.7% in men (242 men out of 554) and 11.9% in women (12 women out of 101). The average age of patients with PFB was 26.80 years (± 2.59), ranging from 22 to 36 years. The age of onset of PFB was between 18 and 20 years for the majority (39.8%), with a mean age of onset of 22.2 years (± 3.6). PFB lesions were pruritic in 84.6% of cases, papular in 96.8%, and/or pustular in 60.2%. The submandibular region was the most affected site (69.8%). Complications were noted in 90.1% of cases in the form of post-inflammatory hyperpigmentation (87%) and keloid scars (3.1%). The risk factors associated with PFB were male sex (p<0.0001; OR=5.7; CI95% [3.07-10.75]), family history of PFB (p<0.0001; OR=5; CI95% [3.35-7.37]), keloid-prone skin (p<0.0001; OR=2.9; CI95% [1.63-4.96]), association with acne keloidalis nuchae (p<0.0001; OR=8.8; CI95% [5.55-14.08]), use of a single-blade razor (p<0.0001; OR=2.5; CI95% [1.69-3.70]), use of a fixed-head razor (p<0.0001; OR=1.8 CI95% [1.28-2.77]), shaving against the grain (p<0.0001; OR = 6.3; CI95%= [4.33-9.08]), non-use of shaving products (p = 0.009; OR = 1.5; CI95%= [1.06-2]) and waxing (p<0.004; OR=2.7; CI95% [1.33-5.77]). On the other hand, the use of clippers (p<0.0001; OR = 0.5 CI95% [0.33-0.65]), pre-shave products (p<0.0001; OR = 0.4 CI95% [0.29-0.61]) and the use of razors with movable heads (p<0.0009; OR = 0.2 CI95% [0.17-0.35]) were protective factors against PFB.
Our study confirms the high incidence of PFB in this population of black men of African descent. A genetic abnormality revealed by shaving must be evoked in the occurrence of PFB. Further genetic and immunohistochemical studies would be needed to support this hypothesis.

The scalp microbiome represents an array of microorganisms important in maintaining scalp homeostasis and mediating inflammation. Scalp microbial dysregulation has been implicated in dermatologic conditions including alopecia areata (AA), dandruff/seborrheic dermatitis (D/SD), scalp psoriasis (SP) and folliculitis decalvans (FD). Understanding the impact of scalp microbial dysbiosis gives insight on disease pathophysiology and guides therapeutic decision making. Herein we review the scalp microbiome and its functional role in scalp conditions by analysis of metagenomic medical literature in alopecia, D/SD, SP, and other dermatologic disease.Increased abundance of Malassezia, Staphylococcus, and Brevibacterium was associated with SD compared to healthy controls. A higher proportion of Corynebacterium, actinobacteria, and firmicutes are present in AA patients, and lower proportions of Staphylococcus caprae are associated with worse clinical outcomes. Decreased prevalence of actinobacteria and Propionibacterium and increased firmicutes, staphylococcus, and streptococcus are associated with scalp psoriasis. Studies of central centrifugal cicatricial alopecia (CCCA) suggest scalp microbial composition contributes to CCCA\'s pro-inflammatory status. The most common organisms associated with FD include methicillin-resistant S. aureus and S. lugdunensis. Antifungals have been a mainstay treatment for these diseases, while other alternatives including coconut oils and shampoos with heat-killed probiotics have shown considerable potential efficacy by replenishing the scalp microbiome.

Folliculitis decalvans (FD) is a rare primary neutrophilic cicatricial alopecia that commonly displays resistance to traditional therapies and remains challenging to treat. Currently, data are lacking with recommendations for therapy-recalcitrant FD. A systematic review was conducted to analyze biologics, small molecule inhibitors, tumor necrosis factor (TNF) inhibitors, Janus kinase (JAK) inhibitors, phosphodiesterase 4 (PDE4) inhibitors, and monoclonal antibodies utilized in the treatment of recalcitrant FD.

BACKGROUND: Current treatment options for Malassezia folliculitis (MF) are limited. Recent research has demonstrated the inhibitory effect of cold atmospheric plasma (CAP) on the growth of Malassezia pachydermatis in vitro, suggesting CAP as a potential therapeutic approach for managing MF.
OBJECTIVE: The objective of our study is to assess the in vitro antifungal susceptibility of Malassezia yeasts to CAP. Additionally, we aim to evaluate the efficacy and tolerability of CAP in treating patients with MF.
METHODS: We initially studied the antifungal effect of CAP on planktonic and biofilm forms of Malassezia yeasts, using well-established techniques such as zone of inhibition, transmission electron microscopy, colony count assay and 2,3-bis(2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide salt assay. Subsequently, a randomized (1:1 ratio), active comparator-controlled, observer-blind study was conducted comparing daily CAP therapy versus itraconazole 200 mg/day for 2 weeks in 50 patients with MF. Efficacy outcomes were measured by success rate, negative microscopy rate and changes in Dermatology Life Quality Index (DLQI) and Global Aesthetic Improvement Scale (GAIS) scores. Safety was assessed by monitoring adverse events (AEs) and local tolerability.
RESULTS: In laboratory investigations, CAP time-dependently inhibited the growth of Malassezia yeasts in both planktonic and biofilm forms. Forty-nine patients completed the clinical study. At week 2, success was achieved by 40.0% of subjects in the CAP group versus 58.3% in the itraconazole group (p = 0.199). The negative direct microscopy rates of follicular samples were 56.0% in the CAP group versus 66.7% in the itraconazole group (p = 0.444). No significant differences were found in the proportion of subjects achieving DLQI scores of 0/1 (p = 0.456) or in the GAIS responder rates (p = 0.588) between the two groups. Three patients in the CAP group and one patient in the itraconazole group reported mild AEs.
CONCLUSIONS: CAP demonstrated significant antifungal activity against Malassezia yeasts in vitro and exhibited comparable efficacy to itraconazole in treating MF patients. Without the associated adverse effects of oral antifungal drugs, CAP can be considered a promising and safe treatment modality for MF.

We present the case of a 53-year-old Caucasian man with a history of intravenous drug use who presented with fever and multiple pustules predominantly affecting hairy areas of the body, with no clinical improvement despite previous antibiotic treatment. Culture of the pustules confirmed Candida albicans infection and histological examination of skin biopsies revealed suppurative granulomas compatible with candidomycetic folliculitis. The patient was successfully treated with systemic antifungals and discharged with resolution of symptoms. Candidomycetic folliculitis is a condition typically associated with brown heroin consumption due to the use of acidic solvent that promotes Candida growth. Clinical manifestations include fever followed by skin lesions, with possible systemic involvement if untreated. Extensive folliculitis with associated fever in an IVDU should raise suspicion of this pathology since early diagnosis and appropriate treatment are crucial to prevent complications.

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Bacterial skin infections represent a significant health care burden. Cellulitis and erysipelas are rapidly spreading, painful, superficial skin infections, usually caused by streptococci or Staphylococcus aureus. Folliculitis is an infection of hair follicles mostly caused by S aureus. Simple folliculitis typically is self-limited. Topical benzoyl peroxide is a first-line nonantibiotic treatment. Mupirocin and clindamycin are topical antibiotic options. For treatment-resistant cases, oral cephalexin or dicloxacillin is an appropriate option. Impetigo is a common, self-limited infection in children. Bullous impetigo is caused by S aureus, and nonbullous impetigo is caused by beta-hemolytic streptococci, S aureus, or both. In most cases, topical mupirocin or retapamulin (Altabax) is effective. Oral antibiotics should be considered for household outbreaks or patients with multiple lesions. Abscesses are red, painful collections of purulence in the dermis and deeper tissues caused by S aureus or polymicrobial infections. Furuncles are abscesses of a hair follicle, whereas carbuncles involve several hair follicles. In recurrent cases of these lesions, culture of the exudate is recommended. Abscess, furuncle, and carbuncle management consists of incision and drainage. Oral antibiotics are not necessary in most cases but should be prescribed for patients with severe immunocompromise or systemic signs of infection. In bacterial skin infections, methicillin-resistant S aureus coverage should be considered for patients with infections that have not improved with treatment.

Keloid scars and folliculitis keloidalis nuchae (FKN) are benign fibroproliferative dermal lesions of unknown aetiology and ill-defined treatment, which typically present in genetically susceptible individuals. Their pathognomonic hallmarks include local aggressive invasive behaviour plus high recurrence post-therapy. In view of this, we investigated proliferative and key parameters of bioenergetic cellular characteristics of site-specific keloid-derived fibroblasts (intra(centre)- and peri(margin)-lesional) and FKN compared to normal skin and normal flat non-hypertrophic scar fibroblasts as negative controls.The results showed statistically significant (P < 0.01) and variable growth dynamics with increased proliferation and migration in keloid fibroblasts, while FKN fibroblasts showed a significant (P < 0.001) increase in proliferation but similar migration profile to controls. A statistically significant metabolic switch towards aerobic glycolysis in the fibroblasts from the disease conditions was noted. Furthermore, an increase in basal glycolysis with a concomitant increase in the cellular maximum glycolytic capacity was also demonstrated in perilesional keloid and FKN fibroblasts (P < 0.05). Mitochondrial function parameters showed increased oxidative phosphorylation in the disease conditions (P < 0.05) indicating functional mitochondria. These findings further suggest that Keloids and FKN demonstrate a switch to a metabolic phenotype of aerobic glycolysis. Increased glycolytic flux inhibition is a potential mechanistic basis for future therapy.