DermNet NZ

Facts about the skin from DermNet New Zealand Trust. Topic index: A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

Gram negative folliculitis

What is gram negative folliculitis?

Gram negative folliculitis is an acne-like disorder caused by a bacterial infection. Gram negative bacteria include Escherichia coli, Pseudomonas aeruginosa, Serratia marcescens, Klebsiella and Proteus species.

The term Gram negative refers to the staining pattern of the organisms in the laboratory. Certain bacteria do not take up a stain known as Gram.

Gram negative folliculitis may result from long term treatment with tetracycline or topical antibiotics.

What does gram negative folliculitis look like?

Gram negative folliculitis is a pustular rash resembling acne. It is often mistaken as a worsening of acne as it usually occurs in patients with existing acne.

In about 80% of patients, lesions are superficial pustules with relatively few papules and comedones. These lesions are usually caused by Klebsiella, Escherichia and Serratia species.

In about 20% of patients lesions are deep, nodular and cyst-like. These are caused by Proteus species which are able to invade deeply into the skin and create pus-filled abscesses and cysts.

Lesions are usually found around the area of the upper lip under the nose, to the chin and cheeks.

Gram negative folliculitis
Gram negative folliculitis

What is the treatment for gram negative folliculitis?

Gram negative folliculitis usually clears promptly with:

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Author: Dr Amanda Oakley Dermatologist, Hamilton, New Zealand. Reviewed by Vanessa Ngan, Staff Writer, February 2014.

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If you have any concerns with your skin or its treatment, see a dermatologist for advice.