Superficial Bacterial Skin Infections - Guidelines for Prescribing Topical Antibiotics for impetigo and folliculitis

Description
  • The skin has an effective system of cells in the dermis and epidermis which helps prevent infection. Skin infections usually occur because bacteria enter through a cut or other disruption in the integrity of the skin.
  • Common skin infections include impetigo, folliculitis, furuncles (boils) and carbuncles.
  • Impetigo (see images at DermNet NZ) is the most common bacterial infection in children and is highly contagious by direct contact.
    • There are two types: non-bullous impetigo, which is the most common, most often occurs in children aged 2 to 5 years (but can affect any age), and occurs on the face or extremities; and bullous impetigo, which usually occurs in babies in the diaper area and axillae.
    • The most common causative agent (up to 74% of cases) is Staphylococcus aureus, including MRSA (methicillin-resistant S. aureus). Streptococcus pyogenes is a possible but less frequent causative agent.
    • Impetigo may recur, usually within 6 months to a year. It very rarely may progress to cellulitis or cause streptococcal glomerulonephritis.
    • Heals within 2-3 weeks without sequelae.
    • Why treat?  Treatment speeds healing of lesions by 1-2 days, decreases spread of lesions, and significantly shortens duration of contagious period.  Treatments are also safe and cost-effective.
    • Risk factors for developing:
      • Summer season
      • Skin barrier disrupted
      • Nasal colonization of S. Aureus
      • Environmental factors: overcrowing, poor hygiene, exposure in day care

  • Folliculitis (see images at DermNet NZ ) occurs when hair follicles become infected. It presents as red, often itchy, papules and/or pustules at the base of the hair shaft. The causative agent is usually S. aureus.
  • Furuncles or boils usually begin as folliculitis which spreads and forms a tender, red swelling with a central pustule.  This may progress to carbuncles, an aggregate of furuncles which penetrates to deeper layers of skin and can lead to cellulitis, a diffuse inflammation of the skin. Furuncles may require systemic antibiotic treatment.
  • For more information and photos, go to:
    Skinsight.com - impetigo, folliculitis
    Mayoclinic.com - impetigo, folliculitis
Signs and Symptoms
  • Non-bullous impetigo
    • Less severe form of impetigo
    • Begins as a single, red sore which forms a blister
    • When the blister breaks, a yellowish exudate dries to form a crust
    • Areas affected are most commonly the face and extremities (arms, legs)
    • Sores are not painful, but may be itchy
    • Multiple lesions may form
    • Minimal redness around lesion
    • Fever is rare
    • Lymph nodes may be tender
  • Bullous impetigo
    • More severe form of impetigo
    • Presents initially as rapidly enlarging soft bullae with sharp margins
    • Blisters do not have a red border, but surrounding skin may be reddened
    • When blister breaks, in 3-5 days, it forms an oozing, yellow crust
    • Areas affected are usually moist diaper areas, armpits and legs
    • Systemic symptoms more likely, such as fever and diarrhea
  • Folliculitis
    • Small red, often itchy, papules and/or pustules at the base of hair shafts especially on neck, groin or armpits
  • Furuncles or boils
    • Secondary lesions which may follow folliculitis
    • Start as a tender, reddened area or a folliculitis
    • Progress to a hard, tender area with a white pustule at the center
    • The pustule may break open and drain or may be surgically opened
    • May progress to carbuncles which are aggregates of furuncles that form an infected area under the skin. Carbuncles are reddened, tender areas from the size of a pea to as large as a golf ball which form one or more pustules and may be accompanied by fever, fatigue and general feeling of malaise
Differential Assessment

Impetigo, folliculitis and furuncles are diagnosed based on symptoms and history. Rule out the following conditions that may present with similar symptoms:

Impetigo

  • Contact dermatitis:
    • Did the patient have any recent contact with an unknown plant, chemical, or topical medicine?
    • Lesions would be limited to exposed area
    • Distinguished by:
      • Sudden onset of severe pruritus
      • Asymmetric distribution
      • Location
      • Allergy history
  • Ecthyma:
    • An ulcerative, deeper form of impetigo usually found on the lower leg area following a trauma to the skin such as a scratch or cut.
    • Punched out ulcers covered with a yellow crust; raised purple margins
    • Commonly on buttocks, thighs, legs, ankles or feet
    • Diabetes or immunosuppression are common co-morbidities
    • Slow to heal; high scarring potential

  • Tinea corporis (ringworm) may form similar looking pustules, but has a clear central area surrounded by red, rash-like ring. Refer to Guideline for Tinea Corporis.

  • Viral skin diseases such as cold sores, shingles or chickenpox which may blister, but have a clear exudate.  Herpes simplex or herpes zoster may resemble impetigo; however, the lesions are not honey-coloured.
    • Cold sores usually occur singly around border of lips. Refer to Guideline for Cold Sores
    • Chickenpox lesions usually develop over the trunk and extremities as well as the face.
    • Shingles follows are unilateral distribution along dermatome tracks

  • Scabies will only affect interdigital and intertriginous areas.

  • Stevens-Johnson syndrome involves high fever with a severe rash and skin-peeling in reaction to a drug.

  • Scalded Skin Syndrome which starts with a localized infection caused by toxins produced by certain strains of S.aureus. When the blisters break the top layer of the skin peels and becomes inflamed resembling a burn. This most often affects infants and children under 5 years old.

  • Burns.

Folliculitis and Furuncles (Boils):

  • Irritant folliculitis:
    • caused by shaving, plucking, waxing, etc. Advise patient to stop hair removal procedure for three months after symptoms of folliculitis resolve. (Topical antibiotics are not effective.)
  • Contact folliculitis:
    • may be caused by petroleum jelly, lanolin, moisturisers, coal tar and overuse of topical corticosteroids.
  • Acne vulgaris which may present as pustules or cysts on face and upper back or gluteal area. Other acne lesions will likely be present. Refer to Guidelines for Acne.
  • Cysts - do not contain pus.
  • Fungal infections -refer to Guideline for Tinea Corporis.
  • Hidradenitis suppurativa which is the presence of boil-like pustules in the axillae and groin - occurs more frequently in women, more frequently in ages 20 - 40 years of age.
  • Fox-Fordyce disease which presents as itchy papules around hair follicles in the armpits, pubic area and around nipple.
  • Carbuncles which are made up of several furuncles forming an infected area under the skin. Carbuncles present as a reddened, tender area which forms one or more pustules and may be accompanied by fever, fatigue and general feeling of malaise.
  • Necrotizing fasciitis and gangrene both of which are rapidly progressing bacterial infections from wound contamination. Refer to physician if area of inflammation around lesion expands rapidly over a few hours.
When to Refer

Patients with superficial bacterial infections often do not require further investigation, however a physician assessment should be recommended in the following situations:

  • Patients with underlying diseases or drug regimens that may cause them to be immunocompromised.
  • If affected area is extensive (larger than 2 or 3 small patches) and / or patient is fevered and fatigued.
  • Suspected bullous impetigo.
  • No significant improvement is seen after 48 hours of topical treatment.
  • Area of inflammation around lesion expands rapidly over a few hours with or without systemic symptoms (fever, chills) - may be cellulitis or erysipelas.
  • Frequent recurrences of impetigo or furuncles.
  • Unable to confirm patient diagnosis of bacterial infection and more serious condition (see Differential Diagnosis above) is suspected. Refer to physician for further investigation and physician-supervised therapy.
  • Suspected MRSA (methicillin-resistant S. aureus):
    • MRSA is impossible to distinguish from methicillin-sensitive S.aureus (MSSA) except by culture. However, there are risk factors which should be examined, such as: recurrent boils or abscesses, previous MRSA infection and underlying medical conditions, close contact with others with the infection and also skin trauma such as scrapes, tattoos, injection drug use, shaving and/or sharing equipment that is not sterilized.  Many people who get MRSA have no risk factors.
    • Topical therapy with mupirocin 2% is a treatment option for MRSA if there are no signs of systemic infection, however there is a high resistance level and treatment failure associated with this use.
    • MRSA infections usually involve the skin, but can cause more serious bone infections or rarely pneumonia.  This is more common in children who also have viral influenza.
    • If MRSA is suspected based on patient history, refer to physician for culture and oral antibiotic therapy.
Treatment

Many mild skin infections are self-limiting and don't require topical antibiotics. Avoid use of topical antibiotics for mild infections to prevent the development of antibiotic resistance.

1) Non-pharmacological treatment:

a) Impetigo

    • Crusts may be removed with warm water or saline compresses applied for 10 minutes, 3 or 4 times daily. Some guidelines recommend the removal of crusts for cosmetic reasons and to help topical antibiotics absorb better; other guidelines suggest it is not necessary.  Conflicting evidence, but it is not harmful to remove the crusts if the patient desires.
    • Topical disinfectants, such as chlorhexidine or hydrogen peroxide, are ineffective.  Soap and water is all that is necessary for cleansing.
    • Wash area up to 4 times a day with soap and water.
    • Avoid scratching or picking sores as this may spread infection.
    • Wash hands often and avoid touching other parts of your body or others after touching lesions.
    • Keep fingernails short.
    • Keep infected person's clothing and towels separate from other members of the family. Launder frequently.

b) Folliculitis and Furuncles

    • Apply saline or warm water compresses to the affected areas for 10 to 15 minutes three times daily. This increases circulation to the area and helps the pustule to rupture and drain.
    • Do not squeeze the sores as this may cause the infection to spread.
    • Wash hands often and after touching affected area.
    • Avoid tight fitting clothing.
    • Shave in the direction of hair growth; avoid shaving affected area.
    • Sores may be covered with non-stick gauze dressings.
    • Try to minimize friction on affected areas.

2)  OTC drug options for superficial bacterial skin infections:

These products have little evidence of efficacy for impetigo or folliculitis, but may be an option.

    • Bacitracin 500IU/g ointment applied to area up to 3 times a day. Bacitracin is only effective against Gram-positive bacteria.
    • Polymyxin B sulfate/ gramicidin cream applied to area up to 3 times a day.
    • Polymyxin B sulfate/ bacitracin ointment applied up to 3 times a day.
    • Polymyxin B sulfate/ bacitracin/ gramicidin ointment up to 3 times a day.
    • Products containing polymyxin combinations have both a Gram-positive and Gram-negative spectrum of activity; however they are not as effective as mupirocin or fusidic acid (see below).
    • Bacitracin has been associated with contact dermatitis.
    • Acetaminophen or ibuprofen may be recommended for pain.

3) Prescription drug options:


a) Impetigo (mild)

    • Patients are considered non-infectious after 48 hours of treatment.
    • Both Mupirocin and Fuscidic acid are equally efficacious.

1. Mupirocin 2% Cream or Ointment  inhibits bacterial protein synthesis. It is considered to be at least as effective as oral antibiotics when used to treat mild impetigo caused by gram-positive bacteria. (Level 1 [likely reliable] evidence).

    • Each gram of product contains 20mg mupirocin. The ointment is a water soluble base which contains polyethylene glycol. The cream is an oil and water based emulsion.
    • Mupirocin penetrates outer layers of skin with minimal systemic absorption.
    • Ointment provides a more occlusive treatment. If necessary, area can be covered with gauze.
    • Dosage: Apply sparingly to infected area, 2-3 times a day for 5 days. If no significant healing occurs after 48 hours refer to physician.
    • Pregnancy: Animal studies have not reported any safety issues but human data is limited. Only small amounts of mupirocin are absorbed after topical use and there are no reports of teratogenicity—risk appears minimal.  However, consider avoiding unless benefit outweighs risk. Systemic agents [penicillins, cephalosporins, clindamycin and erythromycin (except  estolate)] are indicated for impetigo and are safe in pregnancy, so may be an appropriate alternative
    • Lactation: No problems documented with breastfeeding.
    • Anyone with hypersensitivity to propylene glycol should avoid mupirocin ointment.
    • Mupirocin ointment should not be applied intranasally because of propylene glycol content.

2. Fusidic Acid 2% Cream or Sodium Fusidate 2% Ointment inhibits bacterial protein synthesis with comparable activity to mupirocin. It may be bacteriostatic or bactericidal depending on number of bacteria causing the infection. Fusidic acid is inactive against gram-negative bacteria.

    • Each gram of ointment contains 2% sodium fusidate in an ointment base containing lanolin. Each gram of cream contains 2% fusidic acid.
    • Anyone with an allergy to lanolin should avoid fusidic acid ointment.
    • Up to 2% of fusidic acid is absorbed systemically.
    • Ointment provides a more occlusive treatment. If possible, area can be covered with gauze.
    • Dosage: Apply sparingly 3 to 4 times a day for 5 days. If no significant healing occurs within 48 hours refer to physician.
    • Pregnancy: Fusidic acid crosses the placenta when administered systemically. The effects of topical fusidic acid have not been studied in pregnancy, although there are no reports of teratogenicity.  Systemic agents (penicillins, cephalosporins, clindamycin and erythromycin) are indicated for folliculitis and furuncles, and are safe in pregnancy, so may be an appropriate alternative if non-pharmacolgic treatment does not suffice.
    • Lactation: Fusidic acid is excreted to a certain extent in breast milk. The effects of topical fusidic acid have not been studied during breastfeeding.
    • Fucidin-H® has no evidence for improved outcomes vs. fusidic acid monotherapy.

b) Folliculitis and Furuncles

    • Folliculitis should be treated with non-pharmacologic measures for 1 week. If not resolved, topical antibiotic treatment may be indicated.

1. Mupirocin 2% Cream or Ointment  inhibits bacterial protein synthesis of Gram-positive bacteria.

      • Each gram of ointment contains 20mg mupirocin in a water soluble ointment base containing polyethylene glycol. The cream is an oil and water based emulsion.
      • Penetrates outer layers of skin with minimal systemic absorption.
      • Ointment provides a more occlusive treatment. If necessary, area can be covered with gauze.
      • Dosage: Apply sparingly to infected area, 3 times a day for 7 days.

2. Fusidic Acid 2% Cream or Sodium Fusidate 2% Ointment inhibits bacterial protein synthesis with comparable activity to mupirocin. It may be bacteriostatic or bactericidal depending on number of bacteria causing the infection. Fusidic acid is inactive against gram-negative bacteria.

      • Each gram of ointment contains 2% sodium fusidate in an ointment base containing lanolin. Each gram of cream contains 2% fusidic acid.
      • Anyone with an allergy to lanolin should avoid using fusidic acid ointment.
      • Up to 2% of fusidic acid is absorbed systemically.
      • Ointment provides a more occlusive treatment. If necessary, area can be covered with gauze.
      • Dosage: Apply sparingly 3 times a day for 7 days.
Advice / Monitoring
  • Explain non-pharmacological treatment (see non-pharmacological treatment above)
  • Onset of effect 1 – 2 days. Contact your pharmacist or doctor if there is no improvement after 48 hours, or if symptoms worsen.

1) Directions for use of topical antibiotics

Impetigo

    • There is conflicting evidence whether removal of crusts before application of topical antibiotics is necessary. Some guidelines recommend the removal of crusts for cosmetic reasons and to help topical antibiotics absorb better; other guidelines suggest it is not necessary.  
    • If desired, crusts may be removed with warm water or saline compresses applied for 10 minutes, 3-4 times a day.

Folliculitis

    • Warm to hot compresses may be applied to the lesion to bring the exudate to the surface to facilitate rupture and drainage. Lesions should not be squeezed, but allowed to resolve on their own.
    • Apply a small, but adequate amount of cream or ointment to the affected area and massage in gently.
    • A sterile gauze dressing may be applied if necessary.

2) Assess Benefit of Treatment (Impetigo and Folliculitis)

  • Follow up in 48 hours
  • Impetigo: If improvement, continue for 5 days; patient can discontinue treatment of impetigo after 5 days, even if all lesions have not cleared.  
  • Folliculitis: If improvement, continue for 7 days.
  • If no response is seen in 48 hours, refer to physician.
  • If worsens or spreads at any time, refer to physician.
  • If recurrent infections (within a few months), refer to physician to rule out MRSA.

  • Impetigo – check for the following:
    • Vesicles and crusts: Clearing of most lesions.  Advise patient that a normal skin appearance can take 2-3 weeks.
    • Post-inflammatory pigment skin change: If red marks persist on skin after lesions heal, encourage patient it may take several months to resolve.  If no improvement after several months, refer to physician

  • Folliculitis – check for the following:
    • Progression to boils; if develop, refer.
    • Fever: No development of a fever.
    • Pain on palpitation: Pain should be improved by day 3; if not, refer.

3) Assess for Adverse Effects:

  • Adverse effects are uncommon.
  • Persistent irritation, redness, swelling, rash or itching may indicate hypersensitivity - discontinue the medication and refer to physician.
Products

Detailed information on contraindications, cautions, adverse effects and interactions is available in individual drug monographs in the CPS, (e-CPS), Lexi-Comp, AHFS, www.drugs.com or other reliable drug monograph references. For comprehensive drug comparisons, see RxFiles charts (www.rxfiles.ca).
This information should be routinely consulted before prescribing.

 

Over-the-counter products

Ingredient

Directions

Polymyxin B sulfate / gramicidin

Apply three times a day

Polymyxin B sulfate / bacitracin

Apply three times a day

Polymyxin B sulfate / bacitracin / gramicidin

Apply three times a day

Prescription products

Ingredient

Directions

Mupirocin 2%

Apply three times a day for 7 days (folliculitis);

Apply two to three times a day for 5 days (impetigo)

Fusidic acid /sodium fusidate 2%

Apply three times a day for 7 days (folliculitis) or up to 10 days (impetigo)

 


 

 

Prescribing and Billing Details
  • pseudoDIN: 00951100
    • Max of 2 claims per 365 days per patient

  • May prescribe sufficient quantity to treat ONE episode of impetigo or folliculitis, which is usually 5 to 7 days, respectively. 
  • Only products with an official indication from Health Canada for folluculitis or impetigo are considered for these guidelines.  Only the active ingredients in the "products" section are approved for pharmacist prescribing.
Treatment Flowchart
Pharmacist Assessment Documents
References / Suggested Reading
  1. Baddour L. Impetigo. In: UpToDate. Available at www.uptodate.com by subscription.
  2. Green P. Skin Disorders: Bacterial Skin Infections In: Therapeutic Choices. In: RxTx [Internet]. Canadian Pharmacists Association. Available from: http://www.e-therapeutics.ca by subscription.
  3. Hamilton K, Regier L, Jensen B. Anti‐infectives for Common Infections – Overview. In: RxFiles. Available at www.rxfiles.ca by subscription.
  4. Healthy skin – Impetigo. In: C-Health. Available at chealth.canoe.ca. (Free access)
  5. Impetigo. In: DynaMed. Available at https://dynamed.ebscohost.com/ by subscription.
  6. Miller P. Dermatologic Conditions: Bacterial Skin Infections: Impetigo, Furuncles and Carbuncles In: Minor Ailments. RxTx [Internet]. Canadian Pharmacists Association. Available from: http://www.e-therapeutics.ca by subscription.
  7. MUMS Health. Anti-infective Guidelines for Community-acquired Infections. http://www.mumshealth.com/guidelines-tools/anti-infective. Purchase required. Published 2013.
  8. Staph Infections In: Mayo Clinic. www.mayoclinic.org. (Free access)
  9. Stevens DL, Bisno AL, Chambers HF, et al. Practice guidelines for the diagnosis and management of skin and soft tissue infections: 2014 update by the infectious diseases society of America. Clin Infect Dis. 2014;59:147.

Prepared by medSask, Your Medication Information Service
Sponsored by the Saskatchewan College of Pharmacists.
Posted May 2010. Updated March 2016.