Folliculitis (infectious)
Overview
Bacterial
- Folliculitis simplex (Staphylococcus aureus): the commonest pathogen of bacterial folliculitis; follicularly bound erythematous papules and pustules, some with a central crust. The recognition feature is the follicular binding of every single lesion — it separates folliculitis from eczema and from a drug eruption, which take no notice of the follicle. Therapy: antiseptic (octenidine, polyhexanide), topical fusidic acid; systemic only if extensive or abscessing.
- Take care on actinically damaged skin: if a crusted papule persists despite consistent antiseptic treatment it no longer counts as folliculitis — dermoscopy and, if needed, a biopsy belong to the work-up (actinic keratosis, squamous cell carcinoma).
- Streptococcal Folliculitis: The therapy of choice is Flucloxacillin/Cephalexin + Antiseptics plus topical fusidic acid.
- Gram-negative Folliculitis (Klebsiella, Proteus, E. coli, Pseudomonas): typical after long-term tetracycline acne therapy. Therapy: Retinoids (Isotretinoin), antiseptic octenidine, systemic gram-negative antibiotic if necessary.
- Pseudomonas Folliculitis (Whirlpool/Hot-Tub): Antiseptic, oral ciprofloxacin if necessary.
Demodex Folliculitis
- Pathogen: Demodex folliculorum / D. brevis (see card "Tropical & Other Parasitoses" for details).
HSV Folliculitis
- Clinical presentation: grouped vesicles, follicular distribution, stereotypical appearance on the beard or trunk.
Mycotic Folliculitides
- Malassezia / Pityrosporum Folliculitis (= Pityrosporum Folliculitis): Classic features are pustules on the back/décolletage, often misdiagnosed as acne; therapy: topical ciclopirox or Itraconazole for 7 d.
- Tinea barbae / capitis (dermatophytes) in beard/scalp folliculitis.
Differential diagnoses
- Folliculitis decalvans
- Acne vulgaris
- Carbuncle
- Malassezia (Pityrosporum) folliculitis
- Rosacea
- Lichen planopilaris
- Frontal fibrosing alopecia
- Alopecia areata
Practise Folliculitis (infectious) in the app
Flashcards with spaced repetition, exam questions and spot-the-diagnosis on this topic – in DermaFuchs, free of charge.
In the DermaFuchs app: 6 flashcards · 6 clinical images
Open in browser Download on the App StoreMore diseases of the skin appendages
- Acne fulminans
- Hidradenitis suppurativa (acne inversa)
- Acne vulgaris
- Alopecia areata
- Androgenetic alopecia
- Lichen planopilaris
- Milia (milium)
- Perioral dermatitis
Note: This page is intended for medical education and does not replace diagnosis or treatment decisions in individual cases. Treatment and follow-up content is available in the app.