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.
What type of arthritis is commonly seen in DGI?
Purulent gonococcal arthritis
This type of arthritis is characterized by abrupt monoarticular or oligoarticular inflammation.
What joints are most commonly affected by purulent gonococcal arthritis?
Knees, ankles, elbows, and wrists
These joints are frequently involved in cases of DGI.
What serious complications can arise from DGI?
Bacterial meningitis, infective endocarditis, perihepatitis due to PID
These complications highlight the potential severity of untreated DGI.
What diagnostic tests are recommended for all patients suspected of DGI?
Obtain NAAT and culture with antibiotic sensitivity testing from all sites of exposure
This ensures appropriate treatment based on the specific strain of N. gonorrhoeae.
What should be analyzed in patients with gonococcal arthritis?
Synovial fluid analysis
This helps determine the nature of the arthritis (purulent vs. nonpurulent).
What is the typical leukocyte count in purulent arthritis?
50,000–100,000 cells/mm3 with ↑ segmented neutrophils
This indicates a significant inflammatory response.
What initial management steps are recommended for all patients with DGI?
Evaluate for signs of sepsis and start management of sepsis if required
Early intervention is critical for patient safety.
What antibiotics should be initiated for patients with DGI?
Antibiotics for gonorrhea
Treatment should also cover potential chlamydia co-infection.
What is the purpose of prenatal screening for gonorrhea in pregnant individuals?
To prevent neonatal gonococcal infections
Early detection allows for timely treatment and reduces transmission risk.
What routine prophylaxis should be provided to newborns at birth?
Neonatal ophthalmic antibiotic prophylaxis
This is essential to prevent conjunctivitis due to gonococcal infection.
What type of antibiotic is Azithromycin?
Macrolide antibiotic
For which disease is Azithromycin recommended for treatment?
Cat scratch disease
What specific symptom of cat scratch disease does Azithromycin target?
Lymphadenitis
What bacterium is responsible for cat scratch disease?
Bartonella henselae
What is the typical course of illness for cat scratch disease without treatment?
Mild, self-limited course
What is one reason antibiotic therapy is recommended for cat scratch disease?
To prevent further dissemination and infection of other organs
Name two organs that can be infected by Bartonella henselae if untreated.
Liver, eyes
What effect does Azithromycin have on lymphadenopathy?
Decreases lymphadenopathy
What is one benefit of Azithromycin besides treating lymphadenopathy?
Shortens the duration of illness
What are the symptoms of eczema herpeticum?
Fever, malaise, lymphadenopathy, and rash
Eczema herpeticum is a cutaneous manifestation of herpes infection.
Which herpes viruses are usually associated with eczema herpeticum?
HSV-1 or HSV-2
Eczema herpeticum is a cutaneous manifestation of herpes infection.
What pre-existing skin condition is most often associated with eczema herpeticum?
Atopic dermatitis
Eczema herpeticum commonly occurs in patients with pre-existing skin conditions.
Why is eczema herpeticum considered a dermatological emergency?
The rash can disseminate rapidly
Immediate treatment is crucial to prevent complications.
What is the recommended treatment for eczema herpeticum?
Oral or IV acyclovir
Treatment should be initiated as soon as possible.
Fill in the blank: Eczema herpeticum is a cutaneous manifestation of _______.
[herpes infection]
True or False: Eczema herpeticum can occur without any pre-existing skin conditions.
False
It is associated with pre-existing skin conditions, most often atopic dermatitis.
What strains of HPV cause 90% of genital warts?
HPV strains 6 and 11
What is the appearance of lesions caused by HPV strains 6 and 11?
Cauliflower-like, with flat, papular, or pedunculated shape
Where are genital warts commonly found?
On the mucosa or along the epithelium of the anogenital tract
Are genital warts usually symptomatic?
Usually asymptomatic, but may be painful or pruritic in some cases
What application can turn a genital wart lesion white?
3–5% acetic acid
True or False: The application of acetic acid has high specificity for warts.
False
What are some risk factors for HPV?
- Multiple sexual partners
- Unprotected sexual intercourse
What disease is caused by the human herpesvirus 6?
Roseola infantum (exanthem subitum)
Primarily affects infants and young children.
What is a key symptom of Roseola infantum?
High fever
Fever lasts three to five days, known as ‘three-day fever’.
What follows the high fever in Roseola infantum?
Sudden appearance of a truncal rash
Rash may spread to the face and extremities.
What type of lymphadenopathy is often present in Roseola infantum?
Cervical, postauricular, and/or occipital lymphadenopathy
These are common signs accompanying the infection.
What complication may arise from the fever in Roseola infantum?
Febrile seizures
Most patients recover from these seizures without adverse outcomes.
What is the treatment approach for Roseola infantum?
Symptomatic treatment
The disease is self-limiting.
Fill in the blank: Roseola infantum is also known as _______.
exanthem subitum
True or False: Roseola infantum primarily affects adults.
False
It primarily affects infants and young children.
What is oral hairy leukoplakia?
A mucosal disease related to Epstein-Barr virus infection
In which group of individuals is oral hairy leukoplakia most common?
People with HIV
Can oral hairy leukoplakia occur in patients not infected with HIV?
Yes, it can occur in patients taking immunosuppressive medications
What are the characteristic features of oral hairy leukoplakia?
Painless, white, adherent plaques on lateral tongue surfaces
How is the diagnosis of oral hairy leukoplakia typically made?
Clinically, based on the appearance of symptoms and their resolution with antiretroviral therapy
True or False: Oral hairy leukoplakia has malignant potential.
False
What is the most typical cause of a white, corrugated, adherent plaque on the lateral surface of the tongue in a person with HIV?
Oral hairy leukoplakia
What is the treatment for perianal streptococcal dermatitis?
Oral amoxicillin therapy
Amoxicillin is preferred due to its oral emulsion form, particularly for pediatric patients.
What bacteria causes perianal streptococcal dermatitis?
Group A Beta-hemolytic streptococci (GAS)
GAS is the bacterial agent responsible for this condition.
What are the characteristic symptoms of perianal streptococcal dermatitis?
Well-demarcated perianal rash, pseudoexudate, crusting, superficial anal fissures
Affected individuals also experience pruritus, rectal pain during defecation, and blood-streaked stools.
What signs are usually absent in patients with perianal streptococcal dermatitis?
Signs of systemic infection (e.g., fever, abnormal vitals)
This is due to the superficial nature of the infection.
What is a common history associated with perianal dermatitis?
Intrafamilial spread or close contact with people with streptococcal infection
Examples include contact with individuals suffering from pharyngitis.
How is perianal streptococcal dermatitis primarily diagnosed?
Clinically, but can be confirmed with bacterial culture
Diagnosis relies on clinical evaluation and may involve laboratory confirmation.
Why are topical monotherapies ineffective for treating perianal streptococcal dermatitis?
Because deeper layers of the epidermis are infected
This suggests that topical treatments cannot reach the site of infection effectively.
Fill in the blank: Affected individuals typically present with ______ during defecation.
rectal pain
True or False: Penicillin is less effective than amoxicillin for treating GAS infections in pediatric patients.
False
While penicillin is effective, amoxicillin is preferred for its formulation.
