Skin infections can be caused by bacteria, viruses or fungi. Different organisms produce different signs and symptoms when infecting our skin.
A viral skin infection that involves the outer layer of skin, producing tiny white bumps. The centre of the bump may have a depression filled with white material. Molluscum is contagious. The bumps can appear anywhere, including the face. Usually it causes no harm.
Warts are caused by a virus, the human papillomavirus that infects the outer layer of skin.
Shingles are painful, blistering rashs caused by the same virus that causes chickenpox, known as the varicella zoster virus. After a person has had chickenpox, the virus remains dormant in some of the nerves linked to either the spinal cord or the nerves of the head and neck region. If the virus becomes active again, it multiplies and moves along the nerve fibres to the area of skin supplied by those nerves. Shingles then appear in this area.
Herpes simplex is an infection of the skin with the herpes simplex virus. There are two types of herpes virus, called herpes simplex type 1 and herpes simplex type 2. Herpes infection is caught from another person through contact with mouth, eye, or genital secretions or through direct contact with an active lesion. Herpes simplex type 1 usually infects the mouth or eye, and herpes simplex type 2 usually infects the genital area. After the virus infects the person, whether it shows on the skin or not, it goes to local sensory nerves and lies hidden (dormant) until reactivation (recurrence of the herpes infection). Reactivation can occur after a few weeks or even years, when the virus travels to the skin supplied by the nerve and appears as a blister or rash on the skin.
Impetigo is a bacterial infection of the skin, commonly caused by Staphylococcus or Streptococcus. Impetigo is more likely to develop in skin with poor barrier function such as eczema. It may also develop in people with poor skin hygiene or from contact with someone with infected skin.
A boil, or furuncle, is an abscess (infection) of the skin that starts in the deep part of the hair follicle. The infection is usually caused by a bacterium called Staphylococcus aureus. The bacteria causing the boil can occasionally spread from one part of the body to another and from one person to another by skin-to-skin contact and contaminated clothing and towels. Boils are more common in patients with diabetes and those who are overweight. Boils may be single or multiple.
Erysipelas and Cellulitis
Erysipelas is a superficial infection, affecting the upper layers of the skin, while cellulitis affects the deeper tissues. They can overlap, so it is not always possible to make a definite diagnosis between the two. Bacteria (germs) get though a break in the skin. This break can be very small, such as from a scratch, insect bite or injection, or from another skin disease such as athlete’s foot, eczema or a leg ulcer. Erysipelas is usually caused by bacteria called streptococci. Cellulitis is also often caused by streptococci, but many other bacteria may be involved, such as staphylococci.
A fungal infection of the skin folds such as underarms, inframammary area (in women), groin and diaper area in infants. The candida fungus thrives in a warm and moist environment.
Pityriasis Versicolor is a superficial fungal infection of the skin. The condition is often aggravated by excessive sweating. This is caused by the increase in number of the Malassezia fungus which is a skin commensal and causes the rash known as Pityriasis versicolor. This happens most often in warm moist climates. Most people with this condition are perfectly well and healthy. The rash clears with treatment though the pale areas will take a few months to get back to their normal colour. Pityriasis versicolor does not leave scars. Often, the rash does come back.
Ringworm is a common term for superficial fungal infection of the skin which appears as scaly, red, rounded patches with a tendency to form rings. It is known as tinea corporis when it affects the body, and tinea cruris when it affects the groin. Tinea capitis, or ringworm of the scalp, affects mainly children and can cause hair loss. Ringworm of the feet is also known as tinea pedis and is one of the most common fungal infections of the skin. The skin on the soles and toewebs becomes very scaly and peels. It is itchy and occasionally small blisters may appear. The infection can also affect the toenails.
Scabies is an itchy skin condition that can present as red bumps, particularly the hands, skin folds, genitalia and buttocks. The condition is caused by the scabies mite, which is not visible to the naked eye, and can only be seen with the help of a microscope. It is transmitted from humans and often occurs within families. It is easily transmitted during close contact because people with scabies do not have itch or itchy bumps in the first few weeks of infection.