Chapter 19 - Derm Flashcards
1
Q
What term is used to describe a large macule, large papule, and large vesicle.
A
- a large macule is a patch
- a large papule is a plaque
- a large vesicle is a bulla
2
Q
What is the difference between a crusting and a scaling skin lesion?
A
- scaling is a desquamation of the stratum corneum
- crusting is dried exudate and debris
3
Q
How are most fungal skin infections diagnosed?
A
with a KOH prep to identify fungal hyphae
4
Q
Under what circumstances would a shave biopsy be preferred to a punch biopsy? What about the reverse?
A
- a shave biopsy is appropriate for an epidermal or superficial dermal lesion
- a punch biopsy is needed for a deeper lesion
5
Q
In what way do premature infants differ in their response to topical agents?
A
they have a thinner stratum corneum and thus absorb topical agents to a greater degree
6
Q
What is the difference between an ointment, cream, or lotion?
A
- ointments contain little or no water and have maximal water-retaining properties, great for very dry skin
- creams contain 20-50% water and are better for average dryness
- lotions contain more water than creams are are only useful for minimally dry skin
7
Q
How is thickened skin (hyperkeratosis) treated?
A
with keratolytics like salicylic acid, urea, alpha-hydroxy acids, and retinoic acid
8
Q
Which areas of the skin are most susceptible to the side effects of topical corticosteroids and why?
A
the face and groin are most susceptible because the epidermis in these areas is thinner; this is why you should only use low-potency corticosteroids in these areas
9
Q
What are the local side effects of topical corticosteroids?
A
- acne
- hirsutism
- folliculitis
- striae
- pigmentation changes
- atrophy
10
Q
Allergic Contact Dermatitis
A
- an inflammation of the epidermis and superficial dermis secondary to direct contact with a sensitizing substance
- it constitutes a direct T-cell mediated response and requires an earlier exposure for sensitization
- common causes include poison ivy, oak, or sumac; topical lotions, creams, soaps, and perfumes; and nickel
- presents as an erythematous papular/vesicular rash
- treated with topical corticosteroids and avoidance of the agent
11
Q
Primary Irritant Contact Dermatitis
A
- an inflammation of the epidermis and superficial dermis secondary to direct contact with a sensitizing substance
- caused by a caustic substance that irritates the skin in a dose-depdent manner and does not require a prior sensitization
- the classic example is diaper dermatitis, often with secondary C. albicans infection
- presents with erythematous papules without involvement of the inguinal creases; involvement of the inguinal creases, intense confluent erythema, or satellite lesions suggests candidal superinfection
- treated with moisturizers, barrier creams, and ointments containing zinc oxide in addition to frequent diaper changes
12
Q
Seborrheic Dermatitis
A
- believed to be a hypersensitivity to Pityrosporum ovale yeast
- an eruption of greasy, red scales and crusts in areas with high numbers of sebaceous glands, such as the scalp, face, chest, or groin
- infants are often affect by “cradle cap” in which it is limited to the scalp
- should be treated with topical low-dose corticosteroids; sulfur, zinc, or salicylic acid-based shampoos; and a topical anti fungal to eradicate P. ovale
13
Q
Pityriasis Rosea
A
- a hypersensitivity reaction to a virus
- it begins with a solitary, 2- to 5-cm scaly, erythematous lesion on the trunk of extremities, which is present for up to one month
- approximately 1-2 weeks later, there is an eruption of oval erythematous macules and papules in a Christmas tree distribution on the trunk, which can be pruritic
- treatment involves antihistamines
14
Q
Psoriasis
A
- an autosomal dominant disease caused by immune dysregulation and epidermal proliferation
- characterized by well-circumscribed, salmon-colored plaques with a silvery scale, classically on extensor surfaces and the scalp; may also present with pitting of nails and often arise at sites of recent trauma
- histology reveals acanthosis, parakeratosis, collections of neutrophils in the stratum corneum called Munro micro abscesses, and a thinning of epidermis above elongated dermal papillae
- because of this epidermal thinning, bleeding occurs when the scale is picked off, known as the Auspitz sign
- treat with corticosteroids, UV light + psoralen, or immune modulating therapy
15
Q
Miliaria Rubra (Heat Rash)
A
- caused by disrupted sweat ducts near the upper dermis, often secondary to occlusion or friction
- sweat on the skin then produces an inflammatory response and small, erythematous, pruritic papules and vesicles erupt, most often where the skin has been rubbed
- treat with avoidance of occlusive clothing
16
Q
What is erythema multiforme?
A
a collection of hypersensitivity reactions which all have a classic skin lesion described as a target lesion, which is fixed, dull red, and oval in shape with a dusky center
17
Q
Erythema Multiforme Minor
A
- a hypersensitivity reaction to HSV
- presents with symmetric target lesions, which are fixed, dull red, and oval in shape with a dusky center, in an acral distribution
- it often follows a prodrome and generally involves only one mucosal surface, most commonly the mouth
- treated with supportive care and acyclovir
18
Q
Erythema Multiforme Major
A
- a hypersensitivity reaction to M. pneumoniae or a drug
- presents with symmetric target lesions, which are fixed, dull red, and oval in shape with a dusky center, in an acral and truncal distribution
- it often follows a prodrome and involves at least two mucosal surfaces, usually the mouth and eyes
- treated with supportive care and a macrolide if M. pneumoniae is suspected
19
Q
Stevens-Johnson Syndrome
A
- a drug hypersensitivity with widespread, atypical, asymmetric target lesions, blisters, and necrosis
- often preceded by a prodrome and affects at least two mucosal surfaces
- treatment involves supportive care, ophthalmology consultation, and steroids, IVIG, or burn unit admission
20
Q
Toxic Epidermal Necrolysis
A
- a severe drug hypersensitivity with widespread epidermal necrosis and sloughing of the epidermis; Nikolsky sign is usually positive
- there is severe mucous membrane involvement and target lesions are usually absent
- mortality is high due to sepsis, dehydration, and electrolyte abnormalities
21
Q
Tinea Capitus
A
- a fungal infection of the hair
- most often by Trichophyton tonsurans, acquired via human interaction, or Microsporum canis from cats/dogs
- presents with areas with scales and pustules, patchy hair loss, kerions (large, red, boggy nodules), and occipital or posterior cervical lymphadenopathy
- diagnosed with KOH prep or woods light
- treated with 6 weeks of griseofulvin to treat the infection and selenium sulfide shampoo to reduce infectivity
22
Q
Tinea of the Skin
A
- includes tinea corporis, tinea pedis, and tinea curries
- caused by Trichophyton species and Microsporium canis
- presents with oval or circular scaly erythematous patches with partial central clearing
- diagnosed with KOH prep of skin scrapings
- treated with topical anti fungal medications
23
Q
What is tinea unguium?
A
also known as onychomycosis, it is a fungal infection of the nails, causing thickening and yellow discoloration, which requires systemic anti-fungals for treatment
24
Q
Tinea Versicolor
A
- a superficial fungal infection
- caused by Pityrosporum orbiculare, which invades the stratum corneum
- presents with fine, scaly oval macules which may be hypo- or hyper-pigmented and come more prominent with sun exposure
- diagnosed with KOH prep or Woods light examination
- treated with selenium sulfide or systemic antifungal medications
25
What is the difference between an exanthema and an enanthem?
- exanthems are skin rashes
| - enanthems are rashes of the oral mucosa
26
Erythema Infectiosum (Fifth Disease)
- caused by parvovirus B19, transmitted via respiratory secretions
- presents with a slapped-cheek, erythematous macular rash that gives way to a lacy, reticular rash on the trunk and extremities
- may cause asymptomatic anemia, aplastic crisis, or fetal hydrops
- treatment is supportive
27
Roseola Infantum
- caused by HHV-6 or HHV-7
- presents in children younger than 2 with 3-5 days of high fever, which resolves and gives way to a pink papular eruption on the trunk that fads in 1-2 days
28
Varicella
- an intensely pruritic erythematous macular rash that develops after a 7- to 21-day incubation period
- a central vesicle often develops on the macules, given them the appearance of "dew drops on rose petals"
- lesions crust over and are found to be of different ages
- treated with antipyretics, antibacterial soaps to prevent superinfection, antihistamines, and acyclovir for patients with severe complications or in a topical form for those with ophthalmic involvement
- may be complicated by superinfection, necrotizing fasciitis, scarring, Reye syndrome, pneumonia, encephalitis, acute cerebellar ataxia, hepatitis, or zoster
- congenital varicella is a syndrome of zigzag scarring of the skin, shortened or malformed extremities, CNS damage, and eye abnormalities
29
HSV Gingivostomatitis
- an HSV-1 infection that typically presents in young infants
- appears as grouped vesicles and ulcers on the lips and tongue (anterior oral cavity), often causing pain with swallowing; drooling and fever are common
- diagnosis is made by finding epidermal gian cells on Tzanck prep, DFA, or PCR
- the infection usually resolves after 1-2 weeks but can be treated with oral acyclovir
30
Neonatal HSV
- more often due to HSV-2 than HSV-1 and generally acquired during passage through the birth canal
- it presents in the first week of life and is a medical emergency
- may only have a few vesicles or may presents with sepsis, meningoencephalitis, hepatitis, shock, or death
- diagnosis is made by finding epidermal gian cells on Tzanck prep, DFA, or PCR
- requires treatment with acyclovir
31
Hand-Foot-Mouth Disease
- caused by coxsackievirus, usually A16
- presents with vesicles, papules, or pustules on the palms, soles, or fingertips and shallow erosions on the soft palate or tongue
- known as herpangina if only oral lesions are present
- treatment is supportive
32
Molluscum Contagiosum
- caused by poxvirus and often associated with HIV
- presents as small, asymptomatic, flesh-colored papules with central umbilication that may be present anywhere on skin with hair follicles
- lesions are contagious
- treatment requires only observation
33
Louse Infestation
- Pediculus humans causes head and body lice whereas Phthirus pubis causes pubic lice
- infection is associated with crowded living conditions and sharing hats, clothes, combs, or hairbrushes
- presents with itching and white, ovoid bodies attached to the hair shaft, which are eggs
- treat head lice with permethrin shampoo and a comb to remove the nits; treat body or pubic lice with gamma-benzene hexachloride lotion
34
Scabies
- caused by Sarcoptes scabiei
- presents as pruritic papules or vesicles, particularly in the interdigital spaces
- burrows may be visible on the skin and diagnosis should be confirmed with examination of a scraping
- treat with permethrin lotion or lindane; highly contagious so treat all household contacts
- itching may persist up to 30 days after treatment
35
Pityriasis Alba
- presents as dry, scaly, hypopigmented patches, usually on the cheeks
- treated with moisturizers and mild corticosteroids
36
What is vitiligo?
a complete loss of skin pigment in patchy areas due to autoimmune destruction of melanocytes
37
Oculocutaneous Albinism
- a genetic defect in melanin synthesis
| - patients present with white skin and hair, blue eyes, and often photophobia or nystagmus
38
Tuberous Sclerosis
- a neurocutaneous disorder due to a TSC1 mutation on chromosome 9 or TSC2 mutation on chromosome 16
- features follow the HAMARTOMASS acronym: Hamartomas in CNS/skin, Angiofibromas, Mitral regurgitation, Ash-leaf spots (hypo pigmented macules), cardiac Rhabdomyoma, (Tuberous sclerosis), autosomal dOminant, Mental retardation, renal Angiomyolipoma, Seizures or infantile spasms, and Shagreen patches (thickened skin with an orange-peel appearance)
- the number one cause of neonatal cardiac tumors
- also have an increased incidence of subependymal astrocytomas and ungal fibromas
39
Neurofibromatosis Type I
- an autosomal dominant neurocutaneous disorder arising from a mutation of the NF1 tumor suppressor gene on chromosome 17, which encodes a negative regulator of RAS called neurofibromin
- presents with cafe-au-lait spots, Lisch nodules (pigmented iris hamartomas), cutaneous neurofibromas, optic gliomas, and pheochromocytomas
- the neurofibromas are derived from neural crest cells
40
How do congenital and acquired nevi compare?
- congenital are detected in the first six months of life and carry a risk for malignancy
- acquired increase in size and number during puberty and after sunburn; most are junctional and have much lower risk of malignant transformation than congenital nevi
41
Alopecia Areata
- an autoimmune, lymphocyte-mediate injury to hair follicles
- presents acutely with complete hair loss in one to three sharply demarcated areas of the scalp without any inflammation
- alopecia totalis is the subsequent loss of all scalp hair whereas alopecia universalis is the loss of all body and scalp hair
- most patients have regrowth within 1 year without any intervention
42
Trichotillomania
- an obsessive-compulsive-related disorder with hair loss that occurs due to conscious or unconscious pulling or twisting of hair
- area of hair loss typically has irregular borders and hairs are broken off at different lengths, sometimes with perifollicular petechiae and involvement of the eyelashes or eyebrows
- may also be associated with trichophagia, formation of trichobezoars, and abdominal pain with obstruction
- treatment is with habit reversal training, a form of CBT
43
Traction Alopecia
- a form of traumatic alopecia caused by constant traction or friction as in tight hair braids, curlers, vigorous scalp massage, or constant rubbing
- presents as patchy areas of alopecia with thinned, small hairs, but few broken hairs as in trichotillomania
44
Telogen Effluvium
- a form of alopecia caused by an acutely stressful event
- the event converts hairs from a growing phase known as anagen to a resting phase known as telogen
- presents with generalized hair loss 2-3 months after the inciting event, which continues for 3-4 months and then spontaneous regrows
45
Acne Vulgaris
- a skin condition characterized by a progression or collection of comedones, pustules, and nodules
- comedones are colloquially referred to as white and black heads; they arise from androgen-induced upregulation of sebum production by sebaceous glands, which causes an excess of keratin, blocking follicles
- Propionibacterium acnes infection produces lipases, which break down the sebum and release pro-inflammatory fatty acids, resulting in pustule formation
- acne then becomes inflammatory and characterized by erythematous papules, pustules, nodules, and cysts
- treat with benzoylperoxide (an antimicrobial) and vitamin A derivatives, which reduce keratin production; antibiotics may be required for inflammatory acne
- systemic isotretinoin is highly effective but requires pregnancy testing and use of birth control due to the associated teratogenic risk
