18. Infection-related

Bullous impetigo Bullous impetigo after rupture of the bullae Specialty Infectious disease/dermatology Bullous impetigo is a bacterial skin infection caused by Staphylococcus aureus that results in the formation of large blisters called bullae, usually in areas with skin folds like the armpit, groin, between the fingers or toes, beneath the breast, and between the buttocks. It accounts for 30% of cases of impetigo,… read more »

Chlamydia Other names Chlamydia infection Pap smear showing C. trachomatis (H&E stain) Pronunciation /kləˈmɪdiə/, klə-MID-ee-yuh Specialty Infectious disease, gynecology, urology Symptoms None, vaginal discharge, discharge from the penis, burning with urination[1] Complications Pain in the testicles, pelvic inflammatory disease, infertility, ectopic pregnancy[1][2] Usual onset Few weeks following exposure[1] Causes Chlamydia trachomatis spread by sexual intercourse or childbirth[3] Diagnostic method Urine or swab of the cervix, vagina, or urethra[2]… read more »

Anthrax A skin lesion caused by anthrax; the characteristic black eschar Specialty Infectious disease Symptoms Skin form: small blister with surrounding swelling Inhalational form: fever, chest pain, shortness of breath Intestinal form: nausea, vomiting, diarrhea, abdominal pain Injection form: fever, abscess[1] Usual onset 1 day to 2 months post contact[1] Causes Bacillus anthracis[2] Risk factors Working with animals,… read more »

Ecthyma gangrenosum Specialty Infectious diseases Ecthyma gangrenosum is a type of skin lesion characterized by vesicles or blisters which rapidly evolve into pustules and necrotic ulcers with undermined tender erythematous border. “Ecthyma” means a pus forming infection of the skin with an ulcer, “gangrenosum” refers to the accompanying gangrene or necrosis. It is classically associated with Pseudomonas aeruginosa bacteremia, but it is not pathognomonic. [1] Pseudomonas aeruginosa is a gram negative,… read more »

Impetigo Other names School sores,[1] impetigo contagiosa A case of impetigo on the chin Pronunciation /ɪmpɪˈtaɪɡoʊ/ Specialty Dermatology, Infectious disease Symptoms Yellowish skin crusts, painful[2][3] Complications Cellulitis, poststreptococcal glomerulonephritis[3] Usual onset Young children[3] Duration Less than 3 weeks[3] Causes Staphylococcus aureus or Streptococcus pyogenes which spreads by direct contact[3] Risk factors Day care, crowding, poor nutrition, diabetes mellitus, contact sports, breaks in the skin[3][4] Prevention… read more »

Staphylococcal scalded skin syndrome Other names Pemphigus neonatorum, Ritter’s disease,[1] localized bullous impetigo An infant with Staphylococcal scalded skin syndrome Specialty Dermatology Staphylococcal scalded skin syndrome (SSSS) is a dermatological condition caused by Staphylococcus aureus. Signs and symptoms The disease presents with the widespread formation of fluid-filled blisters that are thin walled and easily ruptured, and the patient can be positive… read more »

Syphilis Electron micrograph of Treponema pallidum Specialty Infectious disease Symptoms Firm, painless, non-itchy skin ulcer[1] Causes Treponema pallidum usually spread by sex[1] Diagnostic method Blood tests, dark field microscopy of infected fluid[1][2] Differential diagnosis Many other diseases[1] Prevention Condoms, not having sex[1] Treatment Antibiotics[3] Frequency 45.4 million / 0.6% (2015)[4] Deaths 107,000 (2015)[5] Syphilis is a sexually transmitted infection caused by the bacterium Treponema pallidum subspecies pallidum.[3] The signs and… read more »

Lyme disease Other names Lyme borreliosis An adult deer tick (most cases of Lyme are caused by nymphal rather than adult ticks) Specialty Infectious disease Symptoms Expanding area of redness at the site of a tick bite, fever, headache, tiredness[1] Complications Facial nerve paralysis, arthritis, meningitis[1] Usual onset A week after a bite[1] Causes Borrelia spread by ticks[2] Diagnostic method Based on symptoms, tick exposure,… read more »

Not to be confused with cellulite. Cellulitis Skin cellulitis Specialty Infectious disease Symptoms Red, hot, painful area of skin, fever[1][2] Duration 7–10 days[2] Causes Bacteria[1] Risk factors Break in the skin, obesity, leg swelling, old age[1] Diagnostic method Based on symptoms[1][3] Differential diagnosis Deep vein thrombosis, stasis dermatitis, erysipelas, Lyme disease, necrotizing fasciitis[1][4][5] Treatment Elevation of the affected area[4] Medication Antibiotics such as cephalexin[1][6]… read more »

Folliculitis Folliculitis, single lesion Specialty Dermatology Folliculitis is the infection and inflammation of one or more hair follicles. The condition may occur anywhere on hair covered skin. The rash may appear as pimples that come to white tips on the face, chest, back, arms, legs, buttocks, or head.[1] Signs and symptoms Histopathology of folliculitis of unknown cause, with giant cells surrounding a hair follicle. rash (reddened… read more »