Transitions Derm Flashcards
Autosomal dominant eczema
Filaggrin mutation
Inverse psoriasis
- Likes intertrigonous areas
- No scale – very erythematous
-
In males, perineal inverse psoriasis will involve the scrotum
-
Important because tinea cruris never involves the scrotum
*
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Important because tinea cruris never involves the scrotum
Medication-induced psoriasis
- Beta blockers
- Antimalarials (hydroxychloroquine/chloroquine)
- Lithium
- Interferons
First-line for new-onset psoriasis
Still topical corticosteroids
BUT, we don’t want to keep patients on these forever. If the psoriasis persists, we should try some non-steroid alternatives
Non-steroidal psoriasis treatments
-
Calcipotrene (Vit D analog) or Calcitirol topical cream
- Induces terminal differentiation of keratinocytes
- Risk of hypercalcemia if too much is used, for obv. reasons
-
Tazarotene topical cream
- A newer generation Vit A analog
- Targets retinoid receptor
- Contraindicated in pregnancy, for obv. reasons
-
Topical calcineurin inhibitors (tacrolimus, pimecrolimus)
- Specifically for inverse psoriasis or facial psoriasis
When psoriasis plaques are too widely dispersed, it’s time for. . .
. . . phototherapy (narrow band UVB 3x/week for 3 months, UVA for thick plaques), low-dose methotrexate, acitretin, or cyclosporine.
Arthritis mutilans
End-stage psoriatic arthritis
Indication for systemic therapy: low-dose methotrexate, cyclosporine
Cyclosporine is not a ___ option.
Cyclosporine is not a long-term option. It is a temporizing measure
Recall that it is a calcineurin inhibitor, effectively inhibiting transcription of IL-2.
Long term consequences: Immunocompromise, hypertension, adverse effects on lipid profile, nephrotoxicity
Acitretin
Oral retinoid
Used for systemic treatment of psoriasis
Seborrheic dermatitis at a glance
Greasy, dry, red skin with a dandrufy scale
Often perioral, around the eyes, on the nose, in the ears, or bordering the hair
Possibly due to hypersensitivity against Malassezia furfur (this is why we treat w/ ketoconazole creams)
Shared histologic hallmarks of all forms of eczema
- Spongiosis
- Epidermal changes of scale
- Parakeratosis
90% of patients who are going to have atopic dermatitis have it by age ___.
90% of patients who are going to have atopic dermatitis have it by age 5
Assocaited findings with atopic dermatitis
- Hyperlinear palms and soles (lots of crease lines)
- Keratosis pilaris (perifollicular thickening and redness)
- Ichthyosis vulgaris (diamond-shaped, fish-like scales over skin on arms/legs, especially calves, also assc. w/ filaggrin mutation)
- White dermographism (white urticarial response to koebnerizing stimulus)
Lichen simplex chronicus
Skin change due to chronic itching/scratching
Why should patients with eczema not get the smallpox vaccine?
It may get disseminated over their plaques, which have decreased immune defense capabilities
This is the same reason plaque areas are susceptible to eczema herpeticum.
Grades of steroid creams
I to VI depending on strength, with group VI being most potent.
You should know:
- Group I: Betamethasone
- Group II: Desoximetasone
- Group VI: Dexamethasone or Hydrocortisone
Absorption into skin from ointment, lotion, and cream
In terms of potency/absorption:
Ointment > Cream > Lotion
That is becase ointment is the most oil based, lotion is the most water based, and cream is in-between. You absorb better topically from more oil-based media.
Purine synthesis blockers
Azathioprine
Mycophenolate mofetil
Can be used as oral medications for topical treatment resistant eczema
Patient with chronic lower extremity edema develops bronze coloration and skin cobblestoning of the lower extremity overlying edema. What is the likely diagnosis?
Stasis dermatitis
Unifying symptomatology of all forms of eczema
Xerotosis and pruritis
Contact dermatitis: Irritant vs allergic
- Irritant: Caustic exposure causing xerotic, pruritic rash
- Allergic: Immune-mediated process requiring previous asymptomatic exposure produces xerotic, pruritic rash – Type IV hypersensitivity (like poison ivy). Rash develops 3-4 days after secondary exposure.
Facial dermatitis is often . . .
. . . iatrogenic. Patients may be using face creams that they don’t know are acidic and leaving them on for too long, resulting in effective acid burns.
3 most common allergic dermatitis allergens
- Nickel sulfate
- Neomycin
- Balsam of Peru
Folliculitis
Infected hair follicles
Most commonly Staph. aureus
Advise to avoid touching. Treat w/ antibacterial topicals (often clindamycin) or soaps (benzylperoxide), if extensive w/ oral antibiotics
What is the major factor that determines whether impetigo will be typical “honey crusted” or bullous?
- Whether or not the bacteria have an enzyme that an cleave desmoglein-1
- Phage group 71 Staph aureus w/ exfoliative toxin A and B
- Same group causes staphylococcal scalded skin syndrome if the toxin (not bacetria!) becomes systemic (usually in infants)
Erysipelas
- Group A strep infection of the dermis
- Involves the lymphatics
- Usually preceded by minor trauma
- Most common on face, but can occur anywhere
- Usually assc. fever/chills/malaise
- Treat w/ systemic penicillins (like amoxicillin-clavulonate)
Ecthyma
- Caused by group A streptococci
- Starts as vesicles, these rupture to leave ulcers
- Usually involves shins/dorsal feet
- Treat with oral antibiotics and soaking regularly to remove crust
Ecthyma gangrenosum
- Looks similar to normal ecthyma, but may be raised (a papule) and is darker in coloration, indicating necrosis
- Pseudomonas proliferates within and occludes blood vessels, hence the necrosis
- Caused by pseudomonas rather than streptococci
- Treat w/ IV antibiotics covering pseudomonas
Skin lesions in gonococcemia are due to. . .
. . . immune complex formation, not the presence of the organism
So they will be culture negative.
A cluster of URI symptoms, meningitis, and diffuse polygonal purpuric rashes should make you think . . .
. . . Neisseria meningitidis
Hallmark feature of varicella
Vesicles in multiple stages of development,
for example, new vesicles w/ erythematous base next to skin with ruptured or healed vesicles.
If treating Herpes Zoster with acyclovir does not make patients feel better, why do we do it?
- Two reasons:
- It can slightly shorten the duration of the rash
- It reduces the risk of post-herpetic neuralgia
When should you refer a patient with Shingles to ophthalmology?
When there is involvement of the V1 dermatome
It may lead to keratoconjunctavitis, which can be vision threatening in severe cases
Treating molluscum contagiosum
- Really you don’t need to, it isn’t dangerous and it self resolves in just about anyone who is not immunocompromised
- But, it resolves slowly, months to years, and may be present in an inconvenient area (ie, genital molluscum)
- So, for these cases, and for immunocompromised individuals, you treat it as you would a wart: Removal w/ cryotherapy or something similar.
Which HPV strains are the major causes of cervical cancer?
- 16 and 18 together cause 70% of all cervical cancer
- Most of the rest are the 30’s: 31, 33, 35, 39 (all the odds but 7)
- 51 and 52 bring us to 99%
Majocchi’s granuloma
- Appears as dark reddish, perifolicular granulomas which coalesce into a plaque with defined borders
- Fungal infection of the hair follicles
- Usually self-inoclulated by shaving, and so tends to occur in areas where patients shave
- Requires oral antifungal therapy
Treatment regimen for scabies
- First, full body (neck down) self-applied permethrin cream to kill the mites that are present now
- Two weeks later, repeat to kill the mites that hatch in the meantime
Pathophysiology of acne
- Clogged duct may then be colonized by Propionobacterium acnes, resulting in inflammation and pus formation
Benzoyl peroxide
- Germicidal and comdeolytic agent
- Great for treating open, non-inflammed open comedones (unclogs)
- Will bleach fabric, may be irritating to skin, and may be a cause of allergic contact dermatitis
Salicylic acid for acne
- Beta hydroxy acid that dissolves better in oil
- Dissolves well in sebum and can be comedolytic (open comedones)
Azelaic acid for acne
- Antimicrobial and comedolytic (open comedones)
- Helps w/ post-inflammatory hypopigmentation
Closed vs open comedones
Treatment of choice for closed comedone acne
- Topical retinoids
- Comedolytic and help open up closed comedones
- Can be irritating to skin and are class X teratogens
- Slowly uptitrate dose or frequency to avoid skin irritation
Treating inflammatory acne
- Note: Erythromycin is primarily for pregnant women as a substitute for tetracyclines, which are contraindicated in pregnancy. It is usually used in combination with benzoyl peroxide since P. acnes develops rapid resistance to erythromycin alone.
Pseudofolliculitis barbae
- Common mimic of acne, but only occurs in areas w/ hair and if examined closely is a disease of frequent hair ingrowth
- Ingrown hairs stimulate a foreign body reaction, causing inflammatory papule formation
- Treatment is simply to stop shaving and instead use depilitory, vaniqa cream, or laser hair removal
Post-inflammatory hyperpigmentation
- In patients with hyperpigmented skin or those who tan easily, any inflammatory lesion will cause redistribution of melanin that may last for months
- Can be prevented by aggressive treatment of acne
Treatment for post-inflammatory hyperpigmentation
- Aggressive treatment of underlying acne with topical retinoids and azelaic acid
Nodulocystic acne
- Type of acne that often leads to scarring
- Dermal pockets of inflammation, but not true cysts
- If few lesions, intra-lesional steroid injection can prevent scarring
- If nonresponsive to topical treatment and systemic antibiotics, oral isotretinoin, OCP, or spironolactone (lower dose than diuretic, only used in women) are indicated
- Special requirements for isotretinoin in women, must be on OCP and produce negative pregnancy test
- Retinoids also increase epithelial turnover and can improve scarring
Why does the OCP itself work for acne?
- The estrogen/progesterone suppress testosterone production
- The increased levels of sex hormone binding globulin (SHBG) sequesters more testosteron
- Note that progestin-only OCPs are particularly effective since they have less androgen-receptor binding activity than estrogens
Rules for giving oral isotretinoin
- Pregnancy restrictions
- Limit # of courses to 2 15-20 week courses due to uncertain long-term effects (theoretical risk of bone cancer, but no data to back this up right now)
- Course dosage based on target cumulative dose, not simply mg/kg
Accutane lawsuits
- Teratogenicity
- Risk of increased depressive symptoms (however, this is balanced with reduction in suicidality by improvement in acne: acne increases risk of suicide by 80%)
- Increased risk of IBD, especially ulcerative colitis
Acne fulminans
- Most severe form of cystic acne – requires hospitalization, these people are SICK
- May also be associated with osteolytic bone disease
- Fever, arthralgias, hepatosplenomegaly
- Labs may show elevated ESR, proteinuria, circulating immune complexes, leukocytosis, and anemia
- Treat w/ corticosteroids, isotretinoin, antibiotics
Full approach to acne algorithm
Acne excoriee
- Produces scars that last longer than the acne will
- May indicate neuroticism or self-destructive tendency (Lesch-Nyhan?)
- May require psychiatric assessment
- Requires aggressive acne treatment, regardless of severity, so there is nothing to pick at
Epidermal inclusion cyst
- Walled cysts filled with sebbaceous material and dead keratinocytes
- Treatment requires surgical removal, as if it is simply lysed it will regrow. A surgeon must remove the walls of the cyst to prevent it from reforming.
Steroid acne
- Associated w/ Cushing syndrome and in patients using topical steroid creams
- Monomorphous mildly inflammatory papules and pustules with an absence of comedones
- Treatment is essentially the same as normal acne, but you can coucil the patient that if they reduce or stop steroids then their acne will also stop
When you see someone with acne primarily on the back, especially when it is particularly inflammatory, you should consider. . .
. . . occupational exposure in that area
For example, mechanics who lay on devices that slide under cars
Infantile acne
- Not serious, not concerning, self-limited and will go away
- Parents often ask about it, so reassure them
Systemic causes of ance
- Systemic corticosteroid treatment
- Cushing’s and Pseudo-Cushing’s (SSLC)
- Congenital Adrenal Hyperplasia
- Polycystic ovarian syndrome
- Other medications
What molecule do you measure if you suspect CAH?
17-hydroxyprogesterone
Features that distinguish rosacea from acne
- Typically presents on the central face, while acne is more lateral
- More common in adults
- Four major subtypes (vascular, papulopustular, sebaceous hyperplasia, ocular)
Vascular rosacea
- Flushing with persistent central facial erythema
- May present with or without telangiectasias
- May be aggravated by certain foods
- May treat telangiectasias with laser photocoagulation (a cure) or Mirvaso gel (0.33% brominidine, an alpha 2 agonist, must be applied every day, not curative)
Papulopustular rosacea
- Persistent facial
Sebaceous hyperplastic rosacea
- Thickening of skin and irregular surface nodularity and enlargement
- Classically involves the nose (sometimes rhinophyma), but may also occur on cheeks, chin, forehead, ears
Ocular rosacea
- Can occur w/ other manifestations or in isolation
- Persistent foreign body sensation in eyes with burning, itching, stinging, dryness, photosensitivity, blurred vision, telangiectasia of the sclera, or periorbital edema
- Usually treated w/ oral doxycycline
Predisposing factors to rosacea
- Pale skin (more photopenetration)
- Chronic sun exposure
- Increased density of Demodex folliculorum, a type of microscopic mite
- Especially w/ itchy pustular disease
- Remember, eosinophils cause itch and they are recruited for animal parasitic responses
Rhinophyma
- Consequence of advanced sebaceous hyperpllastic rosacea
Treatments for rosacea
- Very similar to acne, but we avoid salicylic acid and benzoyl peroxide
- Even isotretinoin works
- Lasers and topical bromididine for telangiectasias
Solar comedones
- Aka Maladie du Favreracouchot comdones
- Characteristically in this distribution: centrally in the face, under the eye in areas of sun exposure
- They are open comedones, but not due to acne – the pathophysiology is different
- Can be manually expressed or retinoids can be used for botherome lesions.
Why are blackheads black?
Because oxidized sebum is black. Blackheads are plug-like collections of oxidized sebum.
Hidradenitis
- Another form of follicular occlusion – this one favoring areas of high apocrine gland density (groin, axilla)
- Inflammation w/ some infection – often mixed gram + and -
- Treatments include
- Topical hibiclens/betadine wash or benzoyl peroxide
- Topical clindamycin or metronidazole
- Adalimumab (anti-TNF, for severe or persistent cases, highly effective)
Mupirocin
- Specifically and reversibly binds to bacterial isoleucyl transfer-RNA (tRNA) synthetase
- Topical antibiotic used in treatment of many Group A Strep and Staph aureus infections (impetigo, ecthyma, folliculitis)
Scrotal involvement of dermatologic lesions of the male groin
- Tinea cruris spares the scrotum
- Inverse psoriasis and candidal intertrigo involve the scrotum
- However, only candida will have satellite lesions
Treatment for candidal intertrigo
- Keep affected area dry
- Zinc oxide cream + clotrimazole OR zinc oxide cream + nystatin
- Nystatin is a poly-ene antifungal
Erythrasma
- Bacterial infection of the skin caused by Corynebacterium minutissimum
- Also commonly found in intertrigonous areas and can mimic candidal intertrigo as well as inverse psoriasis
- Will exhibit reddish fluorescence under Wood’s lamp
- Treat w/ topical clindamycin or benzoyl peroxide
Bed bugs
- Obligate parasites that feed on animal blood
- Mostly active during night
- Cause pruritic erythematous maculopapular lesions that are often grouped in a straight line
- Infestations can be recognized by fecal spots on the bedding and exoskeletons.
- The smell of rotting raspberries can be distinctive but is usually seen with a chronic infection
- Treat w/ antihistamines and removal of infestation (often heating the involved room to at least 113.0°F for 90 minutes)
Lice infestation / Pediculosis
- Pruritus, possibly with excoriation, usually localized to scalp or areas of body hair
- Identification of crawling lice in the scalp or hair establishes the diagnosis
- Treat w/ permethrin
Ddx for persistent pruritis of unknown origin
- Cholestasis (bile acid buildup)
- CKD
- Thyroid disease
- Infection (HIV)
- Polycythemia vera
- Malignancy
Why do skin changes in porphyria cutanea tarda and hemochromatosis look so similar?
Because the mechanism is the same!
Iron overload decreases the activity of uroporphyrinogen decarboxylase, the very enzyme that is absent or defective in PCT.
Don’t forget that half of the patients with PCT do not have the genetic form, but an acquired form from Hepatitis C virus
Ddx for erythema nodosum
- Idiopathic (50%)
- IBD
- Sarcoid
- Tuberculosis
- Streptococcal pharyngitis
Herpetic whitlow
- An infection of the dermal and subcutaneous tissue of the fingers caused by HSV-1 (and less commonly HSV-2).
- Often secondary to primary oral lesions.
- Most common in
- Kids who suck their fingers
- Dental assistants and dentists
- Usually self-limiting and resolves within 2–3 weeks
- Can treat w/ acyclovir to shorten the duration
History of competitive swimming, working as lifeguard, or swimming for exercise predispose to infection with. . .
. . . dermatophytes
Trichophyton rubrum especially. Tinea corporis, tinea pedis, tinea cruris, onchomycosis.
The dermatophytes
- Trichophyton
- Epidermophyton
- Microsporum
Imiquimod
TLR 7 agonist that may be given topically as a cream or ointment
Used topically to treat many dermatologic conditions, including actinic keratoses, superficial basal cell carcinomas, herpes simplex infections, and genital warts.
Usually second-line (ex, if herpes simplex is resistant to acyclovir)
Hereditary angioedema
- Caused by Autosomal dominant C1 deficiency
- Characterized by recurrent episodes of swelling without urticaria or pruritus that primarily affects the skin and mucosa of the gastrointestinal and upper respiratory tracts
- Episodes are usually self-limiting and resolve within 2–4 day
- Mechanism involves elevated levels of bradykinin
- Most common triggers are stress and trauma, especially from dental procedure
Marjolin ulcer
- A cutaneous squamous cell carcinoma that arises from chronic, nonhealing wounds
- Often appears above the malleolus or ankle in patients with ulcers from diabetic neuropathy
- Punch biopsy to confirm diagnosis
What are the two major organisms you want to cover for burn wounds?
What is a good regimen for this purpose?
- Staphylococcus aureus (including MRSA) and Pseudomonas aeruginosa
- Vancomycin and cefepime
Breslow depth
You decide a melanoma lesion is malignant.
So now what are you gonna do about it?
Surgical excision with 1-2 cm safety margins and sentinel lymph node study
Amelanotic melanoma
Gold standard treatment for basal cell carcinoma
Mohs micrographic surgery when high risk for recurrence and/or for tumors that involve cosmetically and/or functionally sensitive areas
Otherwise, often excisional biopsy is taken and that is basically it.
Malignant metastatic melanoma is the most common cause of ___ metastases in the US.
Malignant metastatic melanoma is the most common cause of gall baldder metastases in the US.
Best indicator of adequate hydration in the status of a burn and associated SIRS
Urinary output
Gives you an idea of kidney perfusion, and thereby overall organ perfusion
IV fluid volume should be titrated to maintain a urine output of 0.5 mL/kg/h in adults (1 mL/kg/h in children).
Lichen sclerosus
- A chronic inflammatory dermatosis that is characterized by pruritic, white plaques with epidermal atrophy and scarring.
- These may occur either anogenitally (common) or extragenitally.
- Genital lichen sclerosus is associated with an increased risk of squamous cell carcinoma and most commonly affects postmenopausal women.
- After ruling squamous cell carcinoma out w/ biopsy, can treat w/ topical steroids
First-line for mild rosacea
Topical metronidazole
Dimple sign
Positive when squeezing of a papule leads to an inward retraction of the surface
Helps to distinguish a pigmented dermatofibroma from a dysplastic nevus.
If the sign is positive, it is a dermatofibroma, and does not warrant concern unless it continues to grow. Treatment is usually not required. Excision can be considered for cosmetic reasons, symptomatic lesions, or those otherwise suspicious for malignancy.
Patient presents w/ acute cat bite. No immediate signs of infection.
How do you treat?
Administer oral amoxicillin-clavulanate
Following a deep puncture wound from a cat bite, antibiotic prophylaxis should be provided to prevent abscess formation and serious infections such as osteomyelitis, septic arthritis of nearby joints, infectious tenosynovitis, and bacteremia
Skin conditions and associated diseases
Epidermolysis bullosa
- Group of heritable disorders characterized by recurrent blistering in response to trauma
- Presents in infancy, while pemphigus/pemphigoid take a while to develop since they are autoimmune
- Diagnose w/ blister biopsy and fluoroscopic staining
Treating female pattern hair loss
- Usually post-menopause
- Characterized by “follicular miniaturization”
- First-line is minodixil
- Direct vasodilator that increases blood flow under scalp
Treatment for male vs female pattern hair loss
- Male: minodixil OR finasteride
- Female: minodixil
Dermatitis herpetiformis
Often goes with Celiac’s disease, especially when the patient comes in with diarrhea and weight loss! If you biopsy you will find little microabscesses with IgA anti-tissue transglutaminase in them.
Treat initially w/ dapsone initially, but long-term will require gluten-free diet
Sudden-onset severe psoriasis should make you think . . .
. . . HIV
Uses of dapsone
It is an antibiotic used to treat dermatitis herpetiformis (in patients w/ skin involvement in Celiac’s) and to treat leprosy
IT IS NOT A STEROID, IT IS JUST TERRIBLY NAMED
Impetigo bullous vs nonbullous
Five P’s of lichen planus
- Pruritic
- Pink
- Polygonal
- Papules
- Plaques
Lichen planus disease and drug associations
Hepatitis C
ACE inhibitors
Thiazide diuretics
Etiology and treatment of lichen planus
- Often occur at sites of trauma (Koebnerization)
- Etiology is unknown, but often Hepatitis C is present
- Self-limited (<2 years), but can shorten duration with topical corticosteroids
- If extensive, can use oral corticosteroids or phototherapy
Acute palmoplantar/dishidrotic eczema
- Episodic eczema of the palms and soles
- Very pruritic
- Treat w/ topical emollients or corticosteroids
Patient presents with intensely pruritic perivaginal lesion. What is the likely etiology?
Lichen sclerosus
This lesion shows the classical “cigarette paper” appearance
You think a patient has lichen sclerosus. What should you do?
Biopsy!!!
Lichen sclerosus is an autoimmune disease and the slew of growth factors is a risk factor for local squamous cell carcinoma.
They are also, of course, at higher indicence for other autoimmune diseases
If the ___ is involved, you can be confident that the lesion is lichen planus rather than lichen sclerosus
If the vagina is involved, you can be confident that the lesion is lichen planus rather than lichen sclerosus
Lichen slcerosus never affects the vagina in females, but lichen planus does in ~70% of cases
Patient presents with intensely pruritic vulva and dyspareunia. What is the likely diagnosis?
Erosive lichen planus, which is an early form of the disease before it evolves to the polygonal pinkish plaques
Can confirm w/ biopsy
Treatment of any of the three lichenoid disorders should begin with. . .
. . . low-dose topical corticosteroid
