Dermatology Flashcards
What is the causative organism of scabies?
What is the hallmark symptom?
Sarcoptes scabiei var. hominis
Intense pruritis, especially at night
What is the characteristic lesion seen in scabies?
What are the common sites of infestation in scabies?
Serpiginous burrows, typically found in intertriginous areas
Finger webs, wrists, axillae, waistline, and genital area
What is the first-line treatment for scabies?
Topical permethrin 5%
Give one dose, and then repeat in 1 week
What oral medication can be used to treat scabies, especially in cases of widespread infestation or crusted scabies?
Ivermectin
What type of hypersensitivity reaction is associated with the itching in scabies?
Type IV hypersensitivity reaction
A 32-year-old woman presents with intense itching on her hands and wrists that is worse at night. On physical exam, there are small erythematous papules and thin linear burrows between the fingers. What is the most likely diagnosis?
A. Contact dermatitis
B. Psoriasis
C. Scabies
D. Tinea corporis
Scabies
Scabies presents with intense nocturnal itching and characteristic burrows, particularly in intertriginous areas like the finger webs
A 6-year-old boy is diagnosed with scabies after presenting with severe itching and burrows on his hands and wrists. What is the best strategy for managing his household contacts?
A. Only treat family members who show symptoms
B. Treat all close contacts, regardless of symptoms
C. Observe close contacts for 2 weeks before treating
D. Perform skin scrapings on all close contacts
Treat all close contacts, regardless of symptoms
To prevent reinfestation, all close contacts should be treated simultaneously, even if they are asymptomatic
A 65-year-old man presents with left leg pain. He reports progressive erythema and pain of his left lower leg after cutting it while working on his car. His examination is notable for a 5 x 5 cm area of induration and erythema with yellow purulent drainage. The area is warm to touch and tender to palpation. Which of the following is the most appropriate medication for outpatient management of this patient’s condition?
A. Amoxicillin-clavulanate
B. Cephalexin
C. Doxycycline
D. Levofloxacin
Doxycycline
The treatment of cellulitis is based on whether or not there is associated purulence. Patients with purulent cellulitis should receive empiric coverage for MRSA. Oral antibiotics with MRSA coverage include doxycycline, trimethoprim-sulfamethoxazole, clindamycin, and linezolid.
What is the most common pathogen implicated in erysipelas?
Beta-hemolytic streptococci
Describe the degrees of burns?
1st degree (sunburn): Erythema of involved tissue, skin blanches with pressure, the skin may be tender
2nd degree (partial thickness): Skin is red and blistered. The skin is very tender
3rd degree (full thickness): Burned skin is tough and leathery. Skin is non-tender
4th degree: Into the bone and muscle
What body surface area of burns require fluid resusitation in kiddos?
What fluid replacement is most commonly used?
Greater than 10%
Lactated ringers (LR) = LR 3 ml x wt(kg) x % BSA
A 5-year-old child is brought to the emergency department with burns sustained from pulling a pot of boiling water off the stove. Upon examination, the child has erythema and blistering on both anterior lower extremities and the anterior trunk. Using the Rule of Nines, what is the estimated TBSA involvement?
A) 18%
B) 27%
C) 36%
D) 9%
B) 27%
According to the Rule of Nines, each lower extremity accounts for 18% of the TBSA, and the anterior trunk accounts for 18%. Therefore, the total TBSA involvement is 18% (lower extremity) + 18% (lower extremity) + 18% (anterior trunk) = 54%. However, because the burns are only on the anterior portion of the lower extremities and trunk, we take half of each, resulting in 27%.
A 10-year-old boy presents with partial-thickness burns on his right arm, covering approximately 10% of his TBSA. What is the most appropriate initial management for his burns?
A) Apply cold compresses
B) Administer intravenous fluids and cover the burns with a sterile dressing
C) Cover the burns with a sterile dressing only
D) Administer analgesics orally
Administer intravenous fluids and cover the burns with a sterile dressing
This is because the child has greater than 10% TBSA. In children with greater than 10% TBSA intravenous fluids should be given to prevent hypovolemic shock. The initial management of partial-thickness burns involves covering the burns with a sterile, non-adherent dressing to prevent infection and promote healing.
A 2-year-old girl sustains burns from hot bathwater. Upon examination, the burns are limited to her lower extremities and buttocks, with areas of erythema and blistering. What is the most appropriate classification of these burns?
A) Superficial burns (first-degree)
B) Partial-thickness burns (second degree)
C) Full-thickness burns (third degree)
D) Deep partial-thickness burns (fourth degree)
Partial-thickness burn (second degree)
Partial-thickness burns involve damage to the epidermis and part of the dermis, resulting in blistering and erythema. These burns are painful and can take several weeks to heal.
A 6-month-old infant is brought to the clinic with burns from spilled hot coffee. The burns are confined to the palms of both hands. Which of the following is true regarding burns to the palms?
A) They are classified as superficial burns
B) They are considered a minor burn injury
C) Palmar burns typically require surgical debridement
D) Burns to the palms are considered high risk due to the potential for functional impairment
Burns to the palms are considered high risk due to the potential for functional impairment
A 12-year-old girl sustains partial-thickness burns to her face and neck from a house fire. She is conscious and alert, but in pain. Which of the following is the most appropriate initial intervention?
A) Apply ice packs to the burns
B) Administer high-flow oxygen
C) Cover the burns with a clean, dry cloth
D) Initiate fluid resuscitation
Cover the burns with a clean, dry cloth
The immediate priority in managing burns to the face and neck is to cover them with a clean, dry cloth to prevent infection and reduce pain.
Although the patient is at risk for respiratory distress given location of burns high-flow oxygen should be avoided as this can lead to increased inflammation and put them at risk for airway compromise. Their vital signs should be monitored and if oxygen is needed it should be given via low-flow mask.
A 4-year-old boy presents with full-thickness burns on his left forearm and hand. The burned area appears white and leathery. What is the recommended treatment for full-thickness burns?
A) Topical antimicrobial ointment
B) Wet-to-dry dressings
C) Surgical debridement
D) Silver sulfadiazine cream
Surgical debridement
A 3-year-old toddler sustains electrical burns from inserting a metal object into an electrical socket. Which of the following is a potential complication of electrical burns?
A) Hypovolemic shock
B) Respiratory distress syndrome
C) Renal failure
D) Cardiac arrhythmias
Cardiac arrhythmias
What are common drugs that are known to cause drug eruptions?
- Penicillins such as amoxicillin, ampicillin
- Bactrim
- Allopurinol
- NSAIDs
- Calcium channel blockers
- Sulfonamides
- Anticonvulsants
A 6-year-old boy is brought to the emergency department with a history of taking amoxicillin for a recent upper respiratory tract infection. He developed a rash that started on his trunk and spread to his extremities. On examination, the rash consists of erythematous macules and papules with central clearing. There are no mucosal lesions, and the patient is otherwise well-appearing. What is the most likely diagnosis?
A. Erythema multiforme
B. Stevens-Johnson syndrome
C. Toxic epidermal necrolysis
D. Amoxicillin-induced rash
Amoxicillin-induced rash
Drug eruptions typically involve erythematous macules and papules on the trunk and extremeties. There is usually no mucosal involvement.
A 10-year-old boy is brought to the clinic by his parents due to a rash that developed after taking ibuprofen for a fever. The rash consists of well-demarcated erythematous patches with overlying tense bullae, mainly on his trunk and extremities. On examination, there are mucosal lesions, and positive Nikolai’s sign. What is the most likely diagnosis?
A. Toxic epidermal necrolysis
B. Stevens-Johnson syndrome
C. Bullous pemphigoid
D. Drug eruption
Stevens-Johnson Syndrome
Stevens-Johnson syndrome is a severe, life-threatening mucocutaneous reaction typically triggered by medications, including ibuprofen. It is characterized by the sudden onset of fever, target-like lesions (erythematous patches with overlying bullae), and mucous membrane involvement, which may include the oral, ocular, and genital mucosa. The presentation in this case aligns with the hallmark features of SJS, particularly the presence of bullae and the association with ibuprofen use.
What differentiates Stevens-Johnson Syndrome from a non-specific drug eruption?
Is Nikolsky sign present in SJS?
The presence of mucosal involvement, in a drug eruption there will be no mucosal involvement while in SJS mucosal involvement is present. This may include the oral, ocular, or genital mucosa.
SJS also will have erythematous patches with overlying bullae
Yes, but it is not specific as it can be seen in TEN or pemphigoid
What is Nikolsky Sign?
Nikolsky sign refers to the ability to induce blister formation or separation of the skin layers (epidermis) by applying lateral pressure or rubbing on apparently normal-appearing skin adjacent to a blister or erosion.
In a positive Nikolsky sign, the epidermis separates from the underlying dermis with minimal pressure, indicating a loss of cohesion between the skin layers. This sign is commonly seen in conditions associated with skin fragility, such as pemphigus vulgaris, toxic epidermal necrolysis (TEN), and some forms of erythema multiforme, including Stevens-Johnson syndrome (SJS).
What type of hypersensitivity is Stevens-Johnson Syndrome?
Type 4 hypersensitivity causing major keratoncyte apoptosis
