Diagnosis>Organ System>

PATHOGENS

• Staphylococcus aureus (most common in HIV and non-HIV-related folliculitis)
• Pityrosporum ovale (aka Malassezia furfur)
• Demodex folliculorum
• None: eosinophilic folliculitis
• HSV  
• Micrococcus
• Pseudomonas
• Trichophyton
• Gram negative rods (Klebsiella, Enterobacter, Proteus)
• Community-acquired methicillin-resistance Staph. aureus (CA-MRSA)

CLINICAL

• Eosinophilic folliculitis: More common in advanced HIV w/ CD4 typically <250. Hx: severe pruritus w/ lesions over face, neck, upper trunk, upper arms. Spares palms, soles & digital web spaces. Chronic, waxing/waning course. PE: multiple erythematous & edematous (urticarial) papules of follicular distribution w/ a few lesions topped by pustules or crusts. Usually affects upper trunk but also face (esp. forehead), neck & upper arms. Scratching causes excoriated papules, crusts, bleeding, scarring & (in dark-skinned pts) secondary hyperpigmentation. Repeated trauma induces development of prurigo nodularis.
• Papular urticaria: Pruritic, skin-colored or erythematous, non-follicular papules. Similar in appearance to insect bites and in distribution to eosinophilic folliculitis. Histology: nonspecific.
• Pityrosporum (Malassezia) folliculitis: Multiple small, monomorphic follicular-centered papules & pustules affecting upper trunk, arms, occ face. Very pruritic. Histology: pityrosporum spores within follicular lumen.
• Demodex folliculitis: Papular eruption on head, neck, trunk & arms. Histology: presence of mites.
• Staphylococcal folliculitis: Isolated, follicular-centered pustules. Eventual formation of bullae/honey-colored crusts w/erythema, edema & exudate. Most common type in HIV+ pts. Consider CA-MRSA if periumbilical folliculitis or superficial folliculitis arising in areas not typically affected by MSSA, such as the chest, flanks, and scrotum.
• HSV folliculitis: vesiculopustular eruption often from autoinoculation after shaving through HSV lesion on lip/mouth. Usually affects face/beard area. HIV+ pts may present w/ necrotizing folliculitis manifesting as 0.2-1.0 cm papules w/ firm central crusts. Bx may be required for Dx.
• Pseudomonas ("hot tub") folliculitis: multiple pruritic, round, edematous/erythematous lesions w/ central papule/pustule. Acquired from hot tubs, whirlpools, heated swimming pools contaminated w/ Pseudomonas. Lesions appear on trunk +/- extremities 6-72 h post exposure & resolve spontaneously in 7-10 d. Gram negative (non-Pseudomonas) folliculitis: most often presents as sudden exacerbation in pts on long-term ABx for acne as a result of Gram (-) bacterial overgrowth.

DIAGNOSIS

• Skin Bx w/ special stains for fungi & bacteria as well as Gram stain & KOH prep of pustule contents should be performed whenever possible.
• Eosinophilic folliculitis: elevated serum IgE. Peripheral eosinophilia (25-50% of pts). CD4 <250. Skin Bx: follicular spongiosis with infiltration and destruction of follicular wall by eosinophils, folliculocentric inflammation. Micro: bacteria, yeasts or mites are usually not seen
• Other: skin scraping to r/o scabies (Sarcoptes scabiei). Gram stain & Cx to r/o bacterial folliculitis. KOH stain to r/o fungal or Pityrosporum folliculitis.Tzanck smear & viral Cx to r/o HSV.

TREATMENT

• Eosinophilic folliculitis: Topical corticosteroids - usually mid-to-high potency, i.e. fluocinonide 0.05% or betamethasone 0.1%. May decrease inflammation and temporize Sx. On face/sensitive body sites, start w/ lower potency, i.e. hydrocortisone 1%, and escalate PRN.
• Alternative: 5% permethrin cream, apply to affected area qhs x 7 d or until decreased pruritus/lesions, then 1-2x/wk.
• Demodex folliculitis: 5% permethrin cream, apply to affected area qhs x 7d. Alternative: metronidazole 0.75-1% lotion, cream, gel qhs x 4-8 wk.
• Pityrosporum (Malassezia) folliculitis: 2% ketoconazole cream or shampoo, apply to affected area twice-daily.
• Staphylococcal folliculitis: chlorhexidine gluconate (Hibiclens) washes + topical 2% mupirocin to affected areas. If recurrent, eliminate nasal carriage: mupirocin 2% to nares twice-daily x 5-7 d. May repeat q3mos if no resolution. Family members may be nasal carriers; consider Rx'ing.
• Gram negative folliculitis: (1) Pseudomonas folliculitis: Acetic acid 5% compresses x 20 min 2-4 times daily effective for Sx relief. (2) Gram negative (non-Pseudomonas) folliculitis: D/C PO ABx (tetracycline, minocycline etc.) for acne & use benzoyl peroxide wash twice-daily + systemic regimen.
• All cases: Topical antipruritic medications such as menthol-containing lotions, pramoxine, or doxepin 5% cream may help control pruritus.

• Eosinophilic folliculitis: HAART may result in improvement by restoring immune function, but may also cause flare-up during the immune reconstitution period
• Cetirizine 20-40 mg PO once-daily in divided doses (preferred, has anti-eosinophil effect) or hydroxyzine 25-50 mg PO qhs.
• Metronidazole 250 mg PO 3 times daily x 3-4 wk completely cleared lesions in one small study
• Itraconazole 200 mg PO once-daily x 4 wk; if no/inadequate response, retreat w/ itraconazole 300-400 mg once-daily x 4 wk.
• Severe disease: isotretinoin 0.5 mg/kg PO twice-daily x 4-6 wks.
• Severe, acute disease: prednisone (>0.5 mg/kg/d) as short course may be used to induce rapid remission. Relatively contraindicated in immunocompromised population, use as last resort.
• Pityrosporum (Malassezia) folliculitis: itraconazole 200 mg PO once-daily x 4 wks.
• Staphylococcal folliculitis (MSSA): Dicloxacillin 500 mg PO 4 times daily x 7-10 d. PCN allergy: clindamycin 300 mg PO 3 times daily x 7-10 d or doxycycline 100 mg PO twice-daily x 14 d or azithromycin 500 mg, then 250 mg once-daily x 4d or clarithromycin 500 mg PO twice-daily x 7-10 d. Staphylococcal folliculitis (CA-MRSA): TMP/SMX DS PO twice-daily x 7-10d or clindamycin 300 mg PO 3 times daily x 7-10 d or doxycycline 100 mg PO twice-daily x 14 d or minocycline 100 mg PO twice-daily x 14 d (If abscess present, culture pus and modify treatment based on sensitivities).
• HSV folliculitis: acyclovir 400 mg PO 3 times daily or valacyclovir 500 mg PO twice-daily or famciclovir 125 mg PO twice-daily x 5 d.
• Gram negative folliculitis: 1) Pseudomonas folliculitis: Not first line, use only if persistent/immunosuppressed - ciprofloxacin 500 or 750 mg PO twice-daily x 7-10 d. 2) Gram negative (non-Pseudomonas) folliculitis: isotretinoin 0.5-1.0 mg/kg PO twice-daily x 4-6 mos effective. Alternative: PO ABx based on C&S of predominant organisms, usually TMP/SMX DS PO twice-daily or amox/clav 250-500 mg PO 3 times daily.

• Eosinophilic folliculitis: UVB or PUVA (psoralen + ultraviolet A) x 3-6 wks. Generally effective.

Drug Comments

OTHER INFORMATION

• Recommendations are author's opinion. Dx superficial folliculitis in pt w/ small (1-2 mm) erythematous papules/pustules at openings of hair follicles. Not assoc w/ systemic Sx & heals without scarring. Dx deep folliculitis in pt w/ red, swollen, tender, nodular/pustular follicle-centered masses. Involves entire hair follicle & appears as red, swollen nodules/pustules deeper & larger than in superficial folliculitis.
• DDx: eosinophilic folliculitis, infectious folliculitis (fungal - Pityrosporum/Trichophyton, bacterial - Staph/Pseudomonas/other Gram neg, parasitic - Demodex, viral - HSV), papular urticaria, acne, keratosis pilaris, drug eruption, scabies, insect bites, follicular eczema, pustular psoriasis, subcorneal pustular dermatosis (Sneddon-Wilkinson).
• Predisposing factors: friction, perspiration, occlusion (clothing, adhesives), shaving, depilatories, preexisting dermatitis, reduced host resistance (DM, hypogammaglobulinemia, chronic granulomatous disease, meds - systemic corticosteroids or cytotoxic agents), Staph nasal carriage, skin injuries/wounds/abscess, exposure to precipitants (mineral oils, tars, cutting oils, paraffin-based oint).
• May safely treat folliculitis w/ topical corticosteroids & cetirizine while awaiting Bx or Cx results. If results positive, treat specific etiology.
• In bacterial (Staph) folliculitis, local skin care & topical ABx can be used first-line esp. if infection superficial; if area involved widespread or deep infection present, use PO ABx. Drug of choice must cover PCN-resistant S. aureus. For fungal folliculitis, broad-spectrum topical antifungals may be used first-line in superficial cases, w/ PO antifungals reserved for persistent/deep infection.

REFERENCES

REFERENCED WITHIN THIS GUIDE

• Candida spp.
• Initial Evaluation (Zambia specific)
• Staphylococcus spp.