Bacterial skin infections CME

Folliculitis and furunculosis

Created 2008.

Learning objectives

  • Recognise and manage bacterial folliculitis

Clinical features

Hair follicle staphylococcal infections include:

  • Bacterial folliculitis (surface pustules) including sycosis barbae
  • Furunculosis (deeper boils)
  • Abscesses: lesions greater than 0.5cm

Surface infections tend to be itchy, deeper infections are more painful.

Hair follicle staphylococcal infections

Differential diagnosis

The differential diagnosis of superficial folliculitis includes:

Pseudomonas folliculitis

Pseudomonas folliculitis is caused by inadequate chlorination of a hot tub or spa pool. Lesions cluster under the swimming costume. Spa pool folliculitis usually settles by itself, but severe cases can be treated with ciprofloxacin.

Pseudomonas folliculitis

Malassezia folliculitis

Malassezia or pityrosporum folliculitis is due to malassezia infection. It results in irritable monomorphic superficial papulopustules on the upper trunk. Managed with topical and/or systemic antifungal agents.

Malassezia folliculitis

Acne

Acne is characterised by comedones, papules and pustules, sometimes with nodules, cysts and scars.

Irritant folliculitis

Irritant folliculitis is a rash due to shaving e.g. pseudofolliculitis barbae, waxing, or other form of epilation. Local keratolytics and if necessary oral tetracyclines can be helpful.

Pseudofolliculitis barbae

Chemical folliculitis

Chemical folliculitis arises in roadworkers (coal tar) and shearers (sheep's wool).

Pityrosporum folliculitis

Occlusive folliculitis

Occlusive folliculitis arises because of excessive emollient use.

Keratosis pilaris

Keratosis pilaris is characterised by follicles plugged with keratin on upper arms and anterolateral thighs, sometimes erythematous.

Keratosis pilaris

Other spotty rashes

There are many other possible considerations. Non-follicular eruptions sometimes confused with folliculitis include:

  • Miliaria
  • Papular eczema
Miliaria

Hidradenitis suppurativa is sometimes mistaken for boils. Hidradenitis affects the axillae, inguinal, perianal and submammary areas and results in inflamed boil-like nodules that may suppurate and scar. It does not respond to standard antibiotic therapy and S. aureus is infrequently cultured. Refer to a dermatologist for management.

Hidradenitis suppurativa

Management

Contributing irritants and occlusive emollients should be avoided where possible. Avoid plucking, shaving, waxing etc while infection is active and for several more weeks.

Staphylococcal infections are contagious, requiring careful attention to hygiene.

  • Frequent hand-washing
  • Antiseptics for bathing
  • Hot wash clothing, bedding, towels
  • Avoid sharing clothing and towels

Localised staphylococcal infections may be managed using meticulous wound care (including incision and drainage of large furuncles and abscesses) and antiseptics as local application and cleanser. The routine use of topical antibiotics such as fusidic acid or mupirocin is undesirable because of increasing prevalence of topical antibiotic-specific and methicillin-resistant strains of staphylococci.

Oral antibiotics such as flucloxacillin or dicloxacillin may be prescribed for more extensive or recurrent infections but should not be prescribed for trivial reasons. Refer to a specialist if a course of several weeks does not prove helpful; some patients warrant additional treatment with rifampicin and clindamycin.

In recurrent cases, take swabs from active lesions and nostrils to determine antibiotic sensitivity. Consider predisposing causes:

  • Climatic conditions (humidity, occlusive clothing)
  • Underlying skin disease (atopic dermatitis, hidradenitis suppurativa)
  • Iron deficiency
  • Diabetes mellitus
  • Defective neutrophil function (treated with oral vitamin C)
  • Immunodeficiency, including hypogammaglobulinaemia and HIV infection

Activity

Describe the evidence that vitamin c is of benefit for recurrent boils.

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