Folliculitis barbae caused by Staphylococcus lentus: a rarity with its dermoscopy features

INTRODUCTION

Folliculitis is one of the frequent complaints in dermatology clinics. Folliculitis refers to inflammation of the hair follicle caused by infectious and non-infectious conditions. Among infectious etiology, S. aureus bags the first place. However, rare cutaneous flora can cause folliculitis to which treatment will be different and challenging.¹ Here we presented a case report of folliculitis caused by uncommon organism S. lentus with its dermoscopic features.

CASE REPORT

A 28-year-old male patient, teacher by occupation came with complaints of lesions over beard area in the past 20 days. He gave history of similar episodes in the past 4 months, which used to heal and relapse after oral antibiotics given by local doctor. Examination revealed multiple folliculocentric pustules on erythematous base over mandibular region (Figure 1A). Systemic examination was insignificant. His blood parameters were within normal limits. Differentials of gram-negative folliculitis, psuedofolliculitis barbae, and non-infectious folliculitis were considered. Dermoscopic examination was done using DermLite Foto II Pro with 10× magnification and it showed whitish round structures around the follicles with pinkish background. Perifollicular scaling was noted (Figures 1B). Since the lesions were recalcitrant to multiple antibiotics, pus culture was done which cultivated S. lentus. It was sensitive only to gentamycin. Gram stain demonstrated gram positive cocci arranged in grape-like clusters (Figure 2A). Skin biopsy revealed moderately dense perifollicular infiltrate consisting of lymphocytes, histiocytes and occasional plasma cells, and neutrophils scattered in dermis. Moderate infundibular spongiosis and exocytosis, with intraepidermal blister with secondary acantholytic cells were found (Figure 2B). A diagnosis of folliculitis was made and patient was treated appropriately. Unfortunately, patient did not turn up for follow up.

DISCUSSION

Folliculitis is commonly caused by S. aureus. Dermoscopy of folliculitis demonstrates white roundish globular structures around the follicles with red dots and clods.^1,2 In this study, similar dermoscopic pattern were noted except for the vascular elements which showed diffuse erythema around the hair follicles rather red dots or clods. White globular structures corresponded to pustules (microabscesses) and erythema was due to inflammatory capillary dilatation.

S. lentus was found on culture which is a coagulase-negative Staphylococcus that belongs to the S. sciuri group. This bacterial group generally affects animals and rarely found in human beings.³ S. lentus involving skin is not reported in the literature. Furthermore, it was more susceptible to antibiotics as compared to other spp. in the group due to absence of Mec A gene.⁴ On the contrary, it was sensitive only to one antibiotic (gentamycin) in this case. This was due to irrational use of antibiotics prior to consultation.

Clinically, pseudofolliculitis is a close differential which shows pustules around ingrown hairs (Figure 3A). Dermoscopically, it showed curved hairs attached at both resembling a handle bar and white areas and scales (Figures 3).⁵ These features were conspicuously absent in folliculitis. Thus, dermoscopy was helpful in the differentiation folliculitis and psuedofolliculitis. However, it did not delineate the white round structures (pustules) that were produced by different bacteria. Thus, folliculitis, irrespective of etiology, demonstrated white globules around follicles in dermoscopy. This case was reported because of rarity of skin infection by S. lentus which was resistant to many antibiotics

CONCLUSION

To conclude, dermoscopy, being a non-invasive method, gives definitive patterns in folliculitis. Gram stain and culture studies are a must to isolate the causative organism. Culture sensitivity test is highly recommended, in folliculitis, to prevent antibiotic resistance and to treat it with appropriate antibiotics.

Funding: No funding sources

Conflict of interest: None declared

Ethical approval: Not required

REFERENCES

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