Gram-Negative Folliculitis

Gram-Negative Folliculitis

Skin Care
Diseases & Conditions
Contributed byLester Fahrner, MD+1 moreJul 12, 2021

What are the other Names for this Condition? (Also known as/Synonyms)

  • Folliculitis caused by Gram-Negative Bacteria
  • GNF (Gram-Negative Folliculitis)

What is Gram-Negative Folliculitis? (Definition/Background Information)

  • Gram-Negative Folliculitis (GNF) describes a skin condition typically caused by gram-negative bacteria. The gram-negative bacteria causing GNF include Escherichia coli and Pseudomonas aeruginosa
  • Gram stain is a staining technique used in laboratory to identify bacteria. Gram-negative bacteria stain red, while gram-positive bacteria stain blue
  • Gram-Negative Folliculitis develops from long-term management of acne or rosacea through systemic antibiotic therapy. It may also develop because of hot tub use (when it is termed hot tub folliculitis)
  • The treatment measures for Gram-Negative Folliculitis may include the use of oral medications and suitable antibiotics. The prognosis is generally good with adequate treatment and self-care

Who gets Gram-Negative Folliculitis? (Age and Sex Distribution)

  • Gram-Negative Folliculitis may affect individuals of any age category
  • Both males and females are affected
  • Worldwide, individuals of all racial and ethnic background may be affected

What are the Risk Factors for Gram-Negative Folliculitis? (Predisposing Factors)

The risk factors for Gram-Negative Folliculitis may include:

  • Undergoing prolonged treatment of acne or rosacea with systemic antibiotics; it is reported that nearly 4% of the individuals undergoing such treatment may develop Gram-Negative Folliculitis
  • Recent visit to spas, use of hot tubs and swimming pools
  • Individuals with poor immunity, such as HIV-infected individuals, or those with AIDS have a higher risk

It is important to note that having a risk factor does not mean that one will get the condition. A risk factor increases one’s chances of getting a condition compared to an individual without the risk factors. Some risk factors are more important than others.

Also, not having a risk factor does not mean that an individual will not get the condition. It is always important to discuss the effect of risk factors with your healthcare provider.

What are the Causes of Gram-Negative Folliculitis? (Etiology)

Gram-Negative Folliculitis develops when long-term antibiotic therapy (via topical agents and oral tetracycline) of skin conditions, such as acne or rosacea, results in an alteration of the normal flora causing gram-negative bacteria to thrive and flourish.

  • This leads to dissemination of the gram-negative bacteria to other skin sites resulting in Gram-Negative Folliculitis with new acne-like skin lesions (flaring-up of existing condition)
  • The bacteria implicated include Escherichia coli, Pseudomonas aeruginosa, Serratia marcescens, Klebsiella spp. and Proteus spp.

Hot-tub immersions and use of spas may result in hot tub folliculitis and spa pool folliculitis respectively; these are also some types of Gram-Negative Folliculitis. Gram-negative bacteria, such as Aeromonas hydrophila, may cause the infection through open wounds exposed to contaminated water.

What are the Signs and Symptoms of Gram-Negative Folliculitis?

The signs and symptoms of Gram-Negative Folliculitis may vary from one individual to another and may be mild or severe. The signs and symptoms may include:

  • Eruption of pus-filled blisters (pustules) that resemble acne
  • In individuals with pre-existent acne, it may appear as a worsening of the condition
  • Papules, whiteheads, and blackheads, which are noted in acne, are not commonly observed
  • In 20% of the cases, deep nodular cysts may be present
  • The chin, cheeks, and area around the mouth, including the lips may present the lesions

Only skin signs and symptoms are noted; in a majority, there is no systemic involvement observed.

How is Gram-Negative Folliculitis Diagnosed?

A diagnosis of Gram-Negative Folliculitis may involve the following:

  • Physical examination and a complete medical history; a dermatologist will visually examine the lesions to help in the diagnosis
  • Blood tests, analysis of pus, and culture of the fluid being drained, as needed
  • Dermoscopy: Dermoscopy is a diagnostic tool where a dermatologist examines the skin using a special magnified lens
  • Wood’s lamp examination: In this procedure, the healthcare provider examines the skin using ultraviolet light. It is performed to examine the change in skin pigmentation
  • Skin biopsy: A skin tissue biopsy is performed and sent to a laboratory for a pathological examination. The pathologist examines the biopsy under a microscope. After putting together clinical findings, special studies on tissues (if needed) and with microscope findings, the pathologist arrives at a definitive diagnosis

Many clinical conditions may have similar signs and symptoms. Your healthcare provider may perform additional tests to rule out other clinical conditions to arrive at a definitive diagnosis.

What are the possible Complications of Gram-Negative Folliculitis?

Gram-Negative Folliculitis can cause the following complications:

  • Emotional and psychological stress
  • Scarring leading to cosmetic issues
  • Secondary bacterial and fungal skin infections, which may result in fever and other associated signs and symptoms
  • The infection may spread to other skin sites (cellulitis)
  • Recurrence on completion of treatment
  • Antibiotic resistance

How is Gram-Negative Folliculitis Treated?

The treatment of Gram-Negative Folliculitis may involve the following:

  • Use of bacteria-specific/sensitive oral antibiotics such as ciprofloxacin
  • Topical antibiotics with gram-negative coverage include gentamycin, clindamycin, and benzoyl peroxide
  • In severe or chronic cases, isotretinoin is known to be effective

Some forms, such as spa pool folliculitis, may improve and get better even without treatment within a few days.

Self-care (home) remedies may include:

  • Wash the lesions with mild (antibacterial) soap
  • Apply warm compress, if necessary
  • Wash hands before applying topical applications
  • Keep nails trimmed; do not pick the lesions

How can Gram-Negative Folliculitis be Prevented?

Gram-Negative Folliculitis may be prevented by considering the following measures:

  • Taking appropriate treatment for acne and rosacea
  • Avoiding exposure to untreated or poorly-treated swimming pools and hot tubs
  • Getting treatment for any underlying medical condition(s) that may decrease immunity in the individual

What is the Prognosis of Gram-Negative Folliculitis? (Outcomes/Resolutions)

  • The prognosis of Gram-Negative Folliculitis is dependent upon the severity of the condition. However, in a majority of cases, the prognosis is excellent
  • With suitable treatment and self-care measures, an improvement in the condition can be seen within a few days

Additional and Relevant Useful Information for Gram-Negative Folliculitis:

Cleaning the skin too hard with strong chemicals or soaps may aggravate the skin condition. Care must be taken avoid strong soaps and chemicals that could potentially worsen the condition.

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On the Article

Krish Tangella MD, MBA picture
Approved by

Krish Tangella MD, MBA

Pathology, Medical Editorial Board, DoveMed Team
Lester Fahrner, MD picture
Reviewed by

Lester Fahrner, MD

Chief Medical Officer, DoveMed Team


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