Infectious diseases of the skin

Skin diseases caused by defined pathogens in different resistance states of the organism.

A distinction is made between:

• Primary infection: initial infection, i.e. the first contact of an organism with a pathogen.
• Secondary infection: transmission of pathogens, which occurs after the initial infection in addition and with other pathogens. The course of such a disease is usually more severe and shows a variety of symptoms.
• Superinfection: A preceding infection (e.g. viral infection) provides the basis for another (e.g. bacterial infection).
• Double infection: Refers to a simultaneous infection with two different pathogens.

Differentiation according to the origin of the pathogens:

• Endogenous infections occur when the immune system is weakened by the body's own, normally completely harmless flora in the form of a pathogen invasion, e.g. on the skin or from the stomach, intestines and lungs into the patient's own body (like a wound infection by one's own coliform bacteria).
• Exogenous infections are caused by infectious agents from the environment.
• Nosocomial infections are acquired in a hospital, doctor's office, or other medical facility.
• Iatrogenic infections are caused by unintentional introduction of pathogens to the staff themselves or to the patient when a physician or other health care professional is performing medical procedures. See also MRSA, ESBL.
• Opportunistic infections are caused by pathogens to which there is natural immunity under normal immune system function

According to the diseases and pathogens relevant to the dermatologist, the following classification can be made:

• Viruses:
  • Herpes viruses, human: Herpes simplex virus infections
  • Papillomaviruses, human: Papillomavirus infections
  • Measles viruses: Measles
  • Rubella viruses: Rubella
  • Coxsackieviruses: Coxsackie virus infection
  • Poxviruses: Poxvirus infections
  • parvoviruses: parvovirus infections: erythema infectiosum; glove-sock syndrome
  • Retroviruses: HIV infection; HTLV infection (human T-cell lymphotropic virus); T-cell leukemia/lymphoma, adult (HTLV-I+)
  • Haemorrhagic fever viruses: Viral haemorrhagic fever infections
  • Hepatitis viruses: liver disease, skin lesions
  • Coronaviruses: severe systemic diseases (see below COVID-19 infections, skin lesions)
• Fungi:
  • yeasts: yeast infections
  • Dermatophytes: Dermatophyte infections (see below Tinea)
  • moulds: mould infections; mycetoma
  • Fungi as causative agents of systemic mycoses: systemic mycoses.
• Bacteria:
  • Bacteria, gram-positive: staphylococci/streptococci:
    • Pyoderma
    • Erysipelas (cellulitis)
    • Shock syndrome, toxic: shock syndrome, toxic: shock syndrome, toxic, staphylogenic/streptogenic; staphylococcal scalded skin syndrome (SSSS).
  • Staphylococci/Streptococci + mixed infections:
    • Abscesses and phlegmons
    • Fasciitis, necrotizing
    • Ecthyma
    • Hidradenitis suppurativa
  • Corynebacteria:
    • Corynebacterial infections
    • Erysipeloid
    • Anthrax of the skin
  • Bacteria, gram-negative:
    • Pseudomonas infections
    • Gonorrhoea
    • Ulcus molle (chancroid)
    • Granuloma inguinale
    • Tularemia
    • Bartonelloses: Bartonella infections
    • Ehrlichioses
    • Rat bite disease
    • Plague
  • Spirochetes:
    • Borrelia: Lyme disease
    • Treponemas: Treponematoses
  • Mycoplasma: Mycoplasma infections
  • Chlamydia: Chlamydial infections
  • Rickettsiae: Rickettsioses
  • Mycobacteria:
    • Tuberculosis
    • Non-tuberculous mycobacterioses
    • Leprosy
  • Actinomycetes:
    • Actinomycosis
    • Nocardiosis
• Ectoparasites: Epizoonoses
• Protozoa: protozoan infections
• Worms (helminths): worm infections.