Derma Flashcards
What are Group A streptococci (GASs)?
Bacteria, such as Streptococcus pyogenes, that are the most common cause of nonpurulent skin and soft tissue infections (SSTIs)
What types of infections are associated with Group A streptococci?
Erysipelas, nonpurulent cellulitis, lymphangitis
What is the usual point of entry for pathogens in erysipelas?
A minor skin lesion, such as insect bites, rhagades, athlete’s foot, ulcers, or blisters
How do pathogens spread in erysipelas?
Via lymphatic vessels, resulting in infection of the upper dermis
Which areas of the body are most commonly affected by erysipelas?
Lower limbs and face
What characteristic helps differentiate erysipelas from deep tissue infections?
Sharply demarcated erythema
How is cellulitis characterized in contrast to erysipelas?
Erythema with indistinct margins
Why can nonsevere erysipelas be treated with penicillin?
Because GASs typically do not produce penicillinase
What is the most common cause of other, mostly purulent SSTIs?
S. aureus
Fill in the blank: The infections caused by Group A streptococci are nonpurulent skin and soft tissue infections, such as _______.
erysipelas
True or False: Erysipelas is characterized by indistinct erythema.
False
What is the test of choice for diagnosing C. trachomatis and N. gonorrhoeae?
Nucleic acid amplification test (NAAT)
NAAT is preferred due to its rapid results and high sensitivity.
What are the advantages of using NAAT for diagnosing these infections?
Rapid results and high sensitivity
NAAT can also differentiate between C. trachomatis and N. gonorrhoeae infections.
What tests have been widely replaced by NAAT?
Cultures and Gram staining
NAAT’s effectiveness has led to its preference over traditional methods.
True or False: NAAT can differentiate between C. trachomatis and N. gonorrhoeae infections.
True
This capability is one of the key advantages of NAAT.
What is the occurrence rate of disseminated gonococcal infection (DGI) in individuals with gonorrhea?
< 2%
This indicates a relatively rare complication of gonorrhea.
Which demographic is traditionally more affected by DGI?
Individuals < 40 years of age and female individuals
This highlights the age and gender prevalence in DGI cases.
Who appears to be at increased risk for DGI?
Immunocompromised individuals
Their compromised immune systems may contribute to a higher incidence.
What is the primary etiology of DGI?
Hematogenous spread of N. gonorrhoeae from an untreated mucosal gonococcal infection
This emphasizes the importance of treating mucosal infections to prevent DGI.
What are the clinical features of DGI?
Gonococcal arthritis without symptoms of a localized mucosal infection
This can lead to misdiagnosis if not properly evaluated.
What characterizes the arthritis-dermatitis syndrome in DGI?
Polyarthralgias and dermatitis
Symptoms include migratory, asymmetric arthritis and various skin lesions.
What types of skin lesions are associated with DGI?
Vesicular, pustular, or maculopapular lesions, possibly with a necrotic or hemorrhagic center
These lesions are typically fewer than 10 and resolve quickly.
Where are the skin lesions from DGI typically distributed?
Acral surfaces, the trunk
Acral surfaces refer to the extensor surfaces of the hands and feet.
What additional manifestations may occur during the acute phase of DGI?
Fever and chills
These symptoms can indicate the severity of the infection.