What Does Staph Skin Infection Look Like?

Staph skin infection may appear as a red bump, pus-filled blister (folliculitis, infected acne), boil (furuncle or carbuncle), vesicle which may burst and crust over (impetigo), erythema (cellulitis), or skin scalding (scalded skin syndrome). Drainage of pus from lesions is common.

What Causes Staph Skin Infections?

Staph infections are mainly caused by bacterium Staphylococcus aureus, and rarely by S. epidermidis, or S. saprophyticus. In staph carriers, S. aureus, lives in the nose and on the skin, and less commonly in the mouth, mammary glands, urinary, intestinal, and upper respiratory tracts (1). Staphylococcal infections usually remain localized at the portal of entry. What is Staphylococcus aureus?

Who is at Risk for Staph Infections?

Persons at most risk are:

• staph carriers (many individuals carry S. aureus in the nose, throat or skin at some point; 20-30% are colonized persistently, especially health care workers, persons with diabetes, and patients on dialysis)
• newborn infants
• breastfeeding women
• obese persons
• people living in crowded communities or hot climates
• those with skin injuries, surgical wounds
• persons with piercings and fresh tatoos
• persons with skin diseases like atopic dermatitis or seborrhea
• persons with weak immune system, diabetes, cancer, vascular, blood, or lung disease
• patients receiving oral steroids or chemotherapy

continue reading Staph Skin Infections

What is Swimmer’s Ear?

Swimmer’s ear is an inflammation of the ear canal and eventually an earlap, occurring in people who often have wet ears. It occurs mostly in children and teenagers who spend a lot of time in water, but also in persons who sweat a lot or have skin diseases.  
  

Picture 1. Swimmer’s ear commonly occurs in children

Symptoms of Swimmer’s Ear 

Common symptoms are (1):

• ear itching
• pain, especially when pressing on ear ‘tag’ or pulling the ear-pad, or during chewing
• feeling of fullness in the ear
• decreased hearing, noises in the ear 
• ear canal and ear-pad swelling, redness, and skin scalding
• pus draining from the ear canal
• swelling of lymph nodes around the ear

Usually only one ear is involved.

In severe cases with fever, dizziness, or general headache, doctor should be visited promptly.

continue reading Swimmer’s Ear (Otitis Externa)

What is Hot Tub Folliculitis?

Hot tub (spa pool) folliculitis is infection of hair follicles caused by bacterium Pseudomonas aeruginosa which often thrives in new, poorly chlorinated, especially wooden hot tubes or whirlpools (Picture 1).

Picture 1. Hot tub 

Symptoms of Hot Tub Folliculitis

Within eight hours to five days (or even 14 days) of exposure to the bacteria, red, itchy bumps appear that later may develop into small pus-filled blisters (pustules). The rash is likely to be worse in areas where swimsuit holds contaminated water against the skin; face and neck are rarely, and palms and soles are never affected (1). Rarely earache, sore throat or eyes, runny nose, headache, nausea, vomiting, mild fever, breast tenderness, or painful lymph nodes may appear (1). Red wheals up to 3 cm wide may occasionally encircle the bumps (Picture 2), (2).

Picture 2. Hot tub folliculitis.
Click to enlarge >> © Dermnet.com

More Pictures of Hot Tub Folliculitis

continue reading Hot Tub Folliculitis

Folliculitis Pictures

Pictures in this article show staphylococcal folliculitis. Links to pictures of other types of folliculitis.

Picture 1. Staphylococcal folliculitis appears as a red bump, or white pustule.
(source: Samuel Freire da Silva, M.D., Atlasdermatologico)

Picture 2. Staphylococcal folliculitis on the woman’s chest
Click to enlarge >> © Dermnet

Picture 3. Staphylococcal folliculitis on thighs
Click to enlarge >> © Dermnet

continue reading Folliculitis Pictures

1. Obtaining a Sample of Infected Tissue

For staph diagnosis, a sample of infected lesion (nasal secretion, pus, blood, cerebro-spinal fluid, urine, cell aspirate from lungs or bone) has to be obtained. Symptoms of staph infections are often caused by toxins, released from only few staphylococci, so a culture of obviously infected lesion may be negative! From this reason, samples from more than one lesion has to be provided, if possible.

What is Staphylococcus aureus?
Staph Epidemiology
Pictures of Staphylococcal Folliculitis

2. Gram Staining

A clinical sample is placed on a slide and rinsed with:

1. Crystal Violet
2. Iodine Solution (the Mordant)
3. Decolorizer (ethanol)
4. Safranin (the Counterstain)
5. Water

After this procedure, S. aureus and other staphylococci, should be blue, purple or violet under the light microscope, what is denoted as Gram-positive (Gram +), (picture 1). Bacteria, which are colored light pink are denoted as Gram negative (Gram -), (1). Gram staining is performed only, when mixed infection with Gram + and Gram - bacteria is expected.

Picture 1. Gram positive S. aureus,
light microscope, Magn. ~ 100x
Src: phil.cdc.gov

continue reading Lab Tests for Staph

Where S. aureus Lives?

What is Staphylococcus aureus?
Lab tests for staph  

S. aureus lives in:

• healthy people (S. aureus carriers): in the mucosa of the nose, less commonly in the throat, vagina, intestines and lungs; on the skin: mainly in the armpits, under the breasts, and in the groin;
• infected people: in skin lesions, blood, stool, urine, respiratory mucosa, genitals, abscesses of internal organs;
• animals: in pets (fur, skin, nares) and farm animals (cows udders, horses, poultry);
• contaminated food: milk (from infected cow), food prepared and kept outside refrigerator (contamination from infected food worker);
• athletic equipment, toys, workout surfaces;
• air, water, soil, dust (less important sources).

Staph Reservoir

Primary reservoir for S. aureus (including MRSA) is a human. Staph is common in cows (mastitis), poultry, and pets (dogs, cats). In Canada they’ve found MRSA in pigs (1).

How is Staph Infection Spread

Staph may spread from one skin location to another (auto-infection), e.g. by picking the nose followed by scratching the skin, or by clothes. Person to person spread is possible via skin-on-skin contact, or with sharing toys, towels, sport equipment, public showers, sauna, or swimming pools. Infection may also be spread by healthy staph carriers, especially by health personnel. Staph may spread from human to dogs or other pets and then back to the human (2). S. aureus may be found on the skin, hair, nostrils or saliva of dogs. Severe staph endocarditis was reported after a minor dog bite (3). Infection by milking a cow with staph mastitis is possible (4). Staph food poisoning may occur after ingesting food contaminated with staphylococci, released from an infected food worker.

Entry points of staph infection are:

• skin: a hair follicle during minor shaving trauma or depilation, acne, eczema (psoriasis, atopic dermatitis), skin injury, burns, injection, piercing and tattoo punctures, vascular and urinary catheters, surgical wounds;
• respiratory tract: staphylococcal pneumonia may be a complication of influenza or aspiration.

continue reading Staph Epidemiology

Staphylococcus aureus

Staphylococcus aureus (Greek staphyle = bunch of grapes, Latin coccus = spherical bacterium, aureus = golden), or golden staph (pronounced ’staff’), is the most common staphylococcus species causing infections in human.

Lab Tests for Staph
Staph Epidemiology

Staph Infections

S. aureus lives as the part of the normal skin flora in the nose or on the skin in 20-30% of healthy people (staph carriers), (1). However, in even slightly injured skin or mucosa, staph may cause styes, pimples, folliculitis, furuncles, boils (picture 1), swimmer’s ear, sinusitis, epiglotitis, whitlow, breast infection, impetigo, cellulitis, genital infection, or scalded skin syndrome. Infections of internal organs include urinary tract infections, arthritis, pneumonia, infection of veins (thrombophlebitis), lymph nodes (lymphadenitis) or lymph vessels (lymphangitis), bone infection (osteomyelitis) (picture 2), or life threatening  sepsis (staph blood invasion), infection of heart valves (endocarditis),  meningitis, “flesh eating bacteria” infection (necrotizing fasciitis), and toxic shock syndrome. S. aureus enterotoxins may cause food poisoning.

S. aureus and S. epidermidis are among the most common causes of hospital-acquired infections like bloodstream infections, infections of surgical wounds, or pneumonia (2). Staph may also appear in vascular and urinary catheters, prosthetic joints, and heart valves.

Staph skin infection usually appears as a red, warm, painful swelling with a blister, ulcer, or crust, and a drainage (picture 1). Infection may spread into deeper tissues, like bones (picture 2).

Picture 1. A boil on the upper arm	Picture 2. X-ray of child’s legs: osteomyelitis in shin bones (grey patches)

continue reading What is Staphylococcus Aureus?