Bacterial Skin Infections

Cellulitis is a bacterial infection that affects the dermis and the subcutaneous tissue, the two deepest layers of the skin. The skin will become hot, swollen and painful and sometimes you may also see the appearance of blisters. You may also have swollen and painful glands.

Cellulitis occurs when bacteria finds its way into skin that has been broken, for example, by a cut, insect bite, eczema or athlete’s foot. It can affect any part of the body, including the hands, feet, legs and eyes. If left untreated, the infection can spread to other parts of the body, such as the blood, bones or muscles, which may have fatal consequences. Some people are at a higher risk of cellulitis, including those who have poor circulation, a weakened immune system, have lymphoedema, have a surgical wound, diabetics and those who find it difficult to move around or are bed bound. If you have had cellulitis before, you are also at a higher risk of contracting it again.

Impetigo is a highly contagious bacterial skin infection, but fortunately it is not usually serious and is easy to treat.

 Impetigo starts with red sores or blisters which burst to leave crusty, golden-brown patches. These may be itchy and sometimes painful. Impetigo can start anywhere on the body, but most commonly on exposed skin, such as on the arms and face. It can also spread to other parts of the body.

Impetigo usually infects skin that's already damaged, for example, eczema that has been scratched. Impetigo can easily spread to other people. It stops being contagious 48 hours after you start using prescribed medicine or when the patches dry out and crust over.

Anyone can get impetigo, but it is particularly common among young children.

Erysipelas is a superficial bacterial infection that affects the upper layers of the skin. This is in contrast to cellulitis which affects the deeper tissues. However both these infections can overlap, so it is not always possible to make a definite diagnosis between the two.

The most common part of the body to be affected by erysipelas is the legs and face, but any area of skin can be affected. It presents in a similar way to cellulitis, with the skin becoming red, swollen and possible blisters developing.

Just like cellulitis, it is important that erysipelas is treated promptly. If untreated, the infection could spread and cause serious complications such as sepsis (blood poisoning) or meningitis following facial erysipelas. If you have had erysipelas, you are at an increased risk of developing it again at the same site. Just like cellulitis, erysipelas cannot be passed to another person.

This is a common infection of the hair follicles, often caused by ingrown hair, fungus or the follicle becoming blocked by creams or other products applied to the skin. Bacterial folliculitis presents as small, itchy, white, pus-filled bumps.

Often this type of infection heals on its own, but in severe cases it may lead to hair loss.

More commonly known as ‘hot tub folliculitis’, this type of bacterial skin infection is caused by pseudomonas bacteria which is commonly found, as the name suggests, in hot tubs and heated pools where the chlorine and pH levels are not appropriately regulated. With this type of skin infection, the symptoms appear a day or two after exposure to the bacteria. It presents as rash of red, round, itchy bumps, usually on the chest or groin.

It is more common in people with acne or dermatitis and in children, as a child’s skin is thinner than an adult’s.

A boil, or furuncle to give it its medical name, is a hard, painful, pus-filled lump and can appear anywhere on the body. They often go away on their own, but if you keep getting them then you should seek medical advice. People were certain medical conditions, for example HIV or diabetes, are more prone to boils. A group of boils clustered together is known as a carbuncle. These are less common and are more usually found in middle-aged men.

An abscess is a painful pus-filled lump that appears underneath the surface of the skin and can pop up anywhere on the body. If you have an abscess you may also be suffering from other signs of infection, such as localised pain, chills and a high temperature.

An abscess occurs when the immune system sends white blood cells to fight infection caused by bacteria entering the body. As the white blood cells attack the bacteria, some nearby tissue in the affected area dies. This results in a void that fills with pus, forming an abscess.

Skin abscesses most commonly occur on the hands, feet, underarms, trunk, buttocks and genitals. People with certain medical conditions, such as diabetes, an inflammatory condition or a weakened immune system, for example due to HIV or chemotherapy treatment, are more prone to abscesses, although they can happen to anyone.

There are several different causes of erythema multiforme, including mycoplasma bacteria, a type of bacteria that sometimes causes chest infections.

The main symptom is a red rash that starts on the hands or feet, spreading to the limbs, upper body and face. The rash starts as small red spots that become raised patches measuring several centimetres. A person with this particular skin infection will also often have a ‘bulls-eye’ rash, characterised by a dark red centre surrounded by pale pink and dark colour rings. The rash may result in mild itching or discomfort but fortunately the rash fades after two or four weeks. Sometimes the patches merge together, forming painful large red areas. Other symptoms may include a headache, temperature, aching joints, photosensitivity, swollen crusty lips, raw sores inside the mouth, sore red eyes, sores on the genitals and just feeling generally unwell.

Most people with erythema multiforme make a full recovery within a few weeks, but complications can include sepsis, skin damage, eye damage or organ damage. Erythema multitforme may also progress into cellulitis if left untreated.

Methicillin-resistant Staphylococcus aureus, known as MRSA, is a bacterial infection that is resistant to a number of antibiotics, hence it is often referred to as a ‘superbug’.

MRSA lives harmlessly in the nose, armpits, groin or buttocks of around 1 in 30 people. Virtually all of the people carrying MRSA will be unaware of its presence. Carrying it on the skin will not make you ill and it will go away on its own within hours, days, weeks or months. However it can cause an infection if it gets deeper into the body. Healthy people are generally not at risk of an MRSA infection, but people who are staying in hospital are at a heightened risk.

If MRSA gets into your skin, you may experience redness, swelling, pain and pus and the infection site may also feel hot to touch. If the infection gets further into the body, it can also cause aches, chills, a high temperature, dizziness and confusion.

It can be serious, but despite its reputation as a superbug, MRSA can be treated.