Types of Skin Infection
Skin has the largest surface area of all of the body organs and is the most exposed organ. Humans are natural hosts for many bacterial species that colonize the skin as normal flora. Skin infections are common and may be caused by bacteria, fungi or viruses. Bacterial skin infections are common and some are self-limited. Bacterial skin infections caused by corynebacteria include erythrasma, trichomycosis axillaris and pitted keratolysis. Bacteria such as some Staphylococcus species, Corynebacterium spp., Brevibacterium spp and Acinetobacter live on normal skin and cause no harm. Propionibacteria live in the hair follicles of adult skin and contribute to acne. Predisposing factors to infection include minor trauma, preexisting skin disease, poor hygiene, and, rarely, impaired host immunity. Bacterial skin infections include erythrasma and related diseases, impetigo, ecthyma, folliculitis, erysipelas and cellulitis. While there are certainly other bacterial skin infections, they are either uncommon or result from systemic illness.
Impetigo is a bacterial skin infection. It is often called school sores because it most often affects children. Impetigo may be caught from someone else with impetigo or boils, or appear out of the blue. It is quite contagious. Impetigo affects approximately 1% of children. Two clinical types of impetigo exist: nonbullous and bullous impetigo. The nonbullous type is more common and typically occurs on the face and extremities. Bullous impetigo, almost exclusively caused by S aureus, exhibits flaccid bullae with clear yellow fluid that rupture and leave a golden-yellow crust. The infection is carried in the fluid that oozes from the blisters. Rarely, impetigo may form deeper skin ulcers. Some bacteria invade normal skin or wounds (causing wound infection). Bacteria, like viruses, may also sometimes result in exanthems (rashes). The goal is to cure the infection and relieve the symptoms. A mild infection may be treated with a prescription antibacterial cream. More severe cases may require antibiotics, taken by mouth. Wash the skin several times a day, preferably with an antibacterial soap, to remove crusts and drainage. For most patients with impetigo, topical treatment is adequate, either with Polysporin bacitracin or mupirocin (Bactroban), applied three times a day for 7 to 10 days. Systemic therapy may be necessary for patients with extensive disease.
Ecthyma is a skin infection similar to impetigo. Staphylococcus bacteria causes this skin infection. EG may affect patients of any age, although it is commonly reported in infants and elderly patients due to underdeveloped and/or compromised immune systems. Infection may start at the site of an injury with preexisting tissue damage such as scratch, insect bites, dermatitis or excoriations. It occurs when the infection penetrates deep into the dermis, the skin’s second layer, causing painful, itchy sores that develop into pus- or fluid-filled ulcers with hard grayish yellow crusts. The ulcers may cause permanent scarring. Lymph nodes in the affected area may swell. Ecthyma lesion usually begins as a vesicle (small blister) or pustule on an inflamed area of skin. A hard crust that is harder and thicker than the crust of impetigo soon covers this. With difficulty, the crust can be removed to reveal an indurated ulcer that may be red, swollen and oozing with pus. Lesions may stay fixed in size and sometimes resolve spontaneously without treatment, or they may gradually enlarge to a sore of 0.5-3 cm in diameter. The main symptom of ecthyma is a small blister with a red border that may be filled with pus. After the blister goes away, a crusty ulcer appears. Placing a warm wet cloth over the area can help remove ulcer crusts. Drugs Topical mupirocin ointment is very effective. Penicillin should be adequate to treat Streptococci. Surgical Gently debride the crusts
Folliculitis is of skin infection. Folliculitis starts when hair follicles are damaged by friction from clothing, blockage of the follicle, or shaving. Folliculitis occurs when Staphylococcus bacteria. Most infections are superficial, and although they may itch, they’re seldom painful. A more extensive folliculitis of the sebaceous gland (the oily secreting glands) with some involvement of subcutaneous tissues is termed a furuncle (or boil). Tinea barbae is similar to barber’s itch, but the infection is caused by a fungus. Pseudofolliculitis barbae is a disorder occurring primarily in black men. If curly beard hairs are cut too short, they may curve back into the skin and cause inflammation. The signs and symptoms of folliculitis vary, depending on the type of infection. In superficial forms of the disorder, small pimples develop around one or more hair follicles. Anyone can develop folliculitis, but certain factors make you more susceptible to the condition. Medical conditions that reduce your resistance to infection, such as diabetes, chronic leukemia, organ transplantation and HIV/AIDS. Obesity — folliculitis is more common in people who are overweight. Hot moist compresses may promote drainage of extensive folliculitis. Treatment may include antibiotics applied to the skin (mupirocin) or taken by mouth (dicloxacillin), or antifungal medications to control the infection. Herpetic folliculitis responds to valacyclovir, famciclovir, or acyclovir.
Erysipelas is a bacterial infection of the skin. Erysipelas caused by Streptococcus pyogenes (bacteria). Erysipelas is also known as St. Anthony’s Fire. Bacterial inoculation into an area of skin trauma is the initial event in developing erysipelas. Erysipelas may affect both children and adults. The risk factors associated with this infection include a cut in the skin, skin ulcers, and problems with the drainage through the veins or lymph system. People with immune deficiency, diabetes, alcoholism, skin ulceration, fungal infections and impaired lymphatic drainage (e.g., after mastectomy, pelvic surgery, bypass grafting) are also at increased risk. In the past, the face was most commonly involved site of infection, yet now accounts for only up to 20% of cases. The legs are affected in up to 80% of cases. Symptoms and signs of erysipelas are usually abrupt in onset and often accompanied by general illness in the form of fevers, chills and shivering. Affected skin is distinguished from other forms of cellulitis by a well-defined, raised border. The affected skin is red, swollen and may be finely dimpled (like an orange skin). It may be blistered. Bleeding into the skin may cause purpura (purple patches). Treatment for adults is with antibiotics usually a penicillinase – resistant penicillin, cephalosporin, or erythromycin IV or oral depending on the sensitivity. For children less than 3 years old prompt treatment with IV cephalosporins i.e. ceftriaxone is indicated
Cellulitis is an infection of the skin. Cellulitis appears as a swollen, red area of skin that feels hot and tender, and it may spread rapidly. Cellulitis caused by infection with staphylococcus, streptococcus. Cellulitis may progress to serious illness by uncontrolled spread contiguously or via the lymphatic or circulatory systems. Symptoms and signs are usually localised to the affected area but patients can become generally unwell with fevers, chills and shakes. Cellulitis is most common on the lower legs and the arms or hands, although other areas of the body may sometimes be involved. If it involves the face (erysipelas), medical attention is urgent. People with fungal infections of the feet, who have skin cracks in the webspaces between the toes, may have cellulitis that keeps coming back, because the cracks in the skin offer an opening for bacteria. Cellulitis is also a common complication of obesity. Cellulitis is also extremely prevalent amongst dense populations sharing hygiene facilities and common living quarters. Military installations which require communal showers provide such an environment, as it is prevalent among many recruits going through boot camp. Most patients can be treated with oral antibiotics at home, usually for 5 to 10 days. Oral antibiotics used commonly are penicillin, flucloxacillin, cefuroxime or erythromycin. The usual intravenous antibiotics used are penicillin-based antibiotics (e.g. penicillin G or flucloxacillin) or cephalosporins (e.g. cefotaxime or cefazolin) for a few days. Bed rest and elevation of affected limbs is also recommended
Filed under: Skin Disorders