Dermatology study group
A 36-year-old woman presents to her primary care physician due to intense pruritic lesions affecting her
ankles and wrists. She reports that this has never happened before. Medical history is significant for
prior hospitalization for sepsis secondary to methicillin-resistant staphylococcus aureus (MRSA) in the
setting of intravenous drug use. Her only medication is methadone and she does not have any allergies.
On physical examination, there are polygonal violaceous papules affecting the ankles and volar surfaces
of the wrists. Upon closer inspection of the lesions there are Wickham's striae.
What is the most likely diagnosis? and what can be done to diagnosis? - (correct Answer) - Lichen planus
Skin biopsy may be needed to confirm clinical findings
A 49-year-old woman with chronic hepatitis C infection develops a very itchy rash on her forearms,
calves, and buccal mucosa. On exam, multiple polygonal, purple papules are found on the skin. The
buccal mucosa shows a lacy, reticulated pattern. She has taken antihistamines with some relief of
pruritis.
What is the most likely diagnosis? and what can be done to diagnosis? - (correct Answer) - Lichen planus
Skin biopsy may be needed to confirm clinical findings
A 42-year-old man presents with itchy and rough rash along his elbows, knees, and scalp. While he was
previously treated for this disease in childhood, he has been off treatment for years. Physical exam
reveals 2-7 cm pink plaques with overlying silvery scales. When the scale is scratched off, there is
pinpoint bleeding. He is started on an intensive topical therapy regimen with corticosteroids and vitamin
D analog
What is the most likely diagnosis? and what can be done to diagnosis? - (correct Answer) - psoriasis;
there is no confirmatory test for psoriasis the diagnosis is made clinically
A 44-year-old man presents to his family physician with complaints of dry and scaly lesions on his
bilateral elbows. He reports that these lesions developed in his 20's and have been growing in size since
that time. He also reports similar lesions on the anterior portion of his knees. The lesions itch and they
bleed when he scratches them. He denies any additional past medical history. Additional findings include
pitting of the fingernails. Which of the following medications may worsen or exacerbate this patient's
condition?
A. Losartan
B. Oxycodone
,C.Procainamide
D. Propanolol
E. Infliximab - (correct Answer) - D. Beta-blockers (such as propranolol) can exacerbate psoriasis.
Losartan is an angiotensin receptor blocker (ARB) used for the treatment of hypertension. It is not known
to worsen psoriasis. ACE-inhibitors, however, do have an association with worsening psoriasis.
Oxycodone is a narcotic analgesic. It is not known to affect the severity or course of psoriasis.
Procainamide is an anti-arrhythmic medication and does not have an effect on psoriasis. Quinidine,
however, has been implicated in worsening some cases of psoriasis
Infliximab is a TNF-alpha inhibitor indicated for the treatment of chronic and severe psoriasis. When
given for other medical conditions in patients who do not have psoriasis, it can occasionally cause
psoriasis-like lesions to appear
Medications that can exacerbate psoriasis include beta-blockers (such as propranolol), NSAIDs, ACE-
inhibitors, anti-malarial drugs, and lithium.
A 25-year-old woman with no prior medical history presents with complaints of a new skin rash where
she wore her new bracelet. She was in her usual state of health until one month ago when she began
developing an itchy rash on her lower abdomen. The patient works as a fitness instructor. Her family
history is notable for a father with psoriasis and a brother with atopic dermatitis. Physical exam is
notable for an otherwise healthy-appearing female.
Which of the following is the mechanism underlying this patient's skin findings?
A. IgE-mediated hypersensitivity
B. Immune complex-mediated hypersensitivity
C. T-cell-mediated hypersensitivity
D. Fungal infection
E. Deficiency of filaggrin - (correct Answer) - C. In a patient with localized, itchy, scaly plaques of the
abdomen, an allergic contact dermatitis should be suspected (e.g., nickel).
, This is caused by T-cell-mediated cellular damage (type IV hypersensitivity reaction)
A.IgE-mediated (type I) hypersensitivity reactions are characterized by mast cell and basophil release of
histamine and other vasoactive compounds after exposure to an allergen. Examples of type I
hypersensitivity reactions include allergic rhinoconjunctivitis, asthma, and anaphylaxis.
Immune-complex-mediated (type III) hypersensitivity reactions are characterized by deposition of
antigen-antibody immune complexes that result in fixation and activation of complement. Examples
include serum sickness, systemic lupus erythematosus, and rheumatoid arthritis
Fungal infections such as tinea corporis can also present with circular, scaly patches, but typically have a
central clearing and an edge of advancing scale. The anatomic location of the rash in this patient (in an
area of likely contact to metals) further makes allergic contact dermatitis more likely
Deficiency of filaggrin, an epidermal protein that acts to link keratin fibers in epithelial cells, is associated
with disorders of dry skin including atopic dermatitis. Atopic dermatitis can present with itchy, scaly
plaques but are typically localized in the flexural areas in adults.
A 40-year-old man with history of HIV infection presents to the clinic with a red, flaky, oily rash around
his scalp, face, nose, and ears. He has tried low-dose topical steroids, which have not helped. He would
like stronger therapy for his rash.
What medication would be appropriate for this condition? - (correct Answer) - This condition is
Seborrheic Dermatitis
Since he has HIV and is immunocomproised and you've tried low-dose topical steriod, you could then try
a
topical antifungals (e.g., ketoconazole or selenium sulfide)
if he still has systemic therapies for severe or resistant disease:
- oral antifungals (e.g., ketoconazole)
- oral steroids
A 20-year-old student presents to the school's health clinic complaining of a scaly rash on his trunk. He
recalls having a mild fever and headaches a few weeks prior, but did not think much of it. The lesions do
not itch. He loves to play tennis and spends a lot of time outdoors and wear proper attire during
A 36-year-old woman presents to her primary care physician due to intense pruritic lesions affecting her
ankles and wrists. She reports that this has never happened before. Medical history is significant for
prior hospitalization for sepsis secondary to methicillin-resistant staphylococcus aureus (MRSA) in the
setting of intravenous drug use. Her only medication is methadone and she does not have any allergies.
On physical examination, there are polygonal violaceous papules affecting the ankles and volar surfaces
of the wrists. Upon closer inspection of the lesions there are Wickham's striae.
What is the most likely diagnosis? and what can be done to diagnosis? - (correct Answer) - Lichen planus
Skin biopsy may be needed to confirm clinical findings
A 49-year-old woman with chronic hepatitis C infection develops a very itchy rash on her forearms,
calves, and buccal mucosa. On exam, multiple polygonal, purple papules are found on the skin. The
buccal mucosa shows a lacy, reticulated pattern. She has taken antihistamines with some relief of
pruritis.
What is the most likely diagnosis? and what can be done to diagnosis? - (correct Answer) - Lichen planus
Skin biopsy may be needed to confirm clinical findings
A 42-year-old man presents with itchy and rough rash along his elbows, knees, and scalp. While he was
previously treated for this disease in childhood, he has been off treatment for years. Physical exam
reveals 2-7 cm pink plaques with overlying silvery scales. When the scale is scratched off, there is
pinpoint bleeding. He is started on an intensive topical therapy regimen with corticosteroids and vitamin
D analog
What is the most likely diagnosis? and what can be done to diagnosis? - (correct Answer) - psoriasis;
there is no confirmatory test for psoriasis the diagnosis is made clinically
A 44-year-old man presents to his family physician with complaints of dry and scaly lesions on his
bilateral elbows. He reports that these lesions developed in his 20's and have been growing in size since
that time. He also reports similar lesions on the anterior portion of his knees. The lesions itch and they
bleed when he scratches them. He denies any additional past medical history. Additional findings include
pitting of the fingernails. Which of the following medications may worsen or exacerbate this patient's
condition?
A. Losartan
B. Oxycodone
,C.Procainamide
D. Propanolol
E. Infliximab - (correct Answer) - D. Beta-blockers (such as propranolol) can exacerbate psoriasis.
Losartan is an angiotensin receptor blocker (ARB) used for the treatment of hypertension. It is not known
to worsen psoriasis. ACE-inhibitors, however, do have an association with worsening psoriasis.
Oxycodone is a narcotic analgesic. It is not known to affect the severity or course of psoriasis.
Procainamide is an anti-arrhythmic medication and does not have an effect on psoriasis. Quinidine,
however, has been implicated in worsening some cases of psoriasis
Infliximab is a TNF-alpha inhibitor indicated for the treatment of chronic and severe psoriasis. When
given for other medical conditions in patients who do not have psoriasis, it can occasionally cause
psoriasis-like lesions to appear
Medications that can exacerbate psoriasis include beta-blockers (such as propranolol), NSAIDs, ACE-
inhibitors, anti-malarial drugs, and lithium.
A 25-year-old woman with no prior medical history presents with complaints of a new skin rash where
she wore her new bracelet. She was in her usual state of health until one month ago when she began
developing an itchy rash on her lower abdomen. The patient works as a fitness instructor. Her family
history is notable for a father with psoriasis and a brother with atopic dermatitis. Physical exam is
notable for an otherwise healthy-appearing female.
Which of the following is the mechanism underlying this patient's skin findings?
A. IgE-mediated hypersensitivity
B. Immune complex-mediated hypersensitivity
C. T-cell-mediated hypersensitivity
D. Fungal infection
E. Deficiency of filaggrin - (correct Answer) - C. In a patient with localized, itchy, scaly plaques of the
abdomen, an allergic contact dermatitis should be suspected (e.g., nickel).
, This is caused by T-cell-mediated cellular damage (type IV hypersensitivity reaction)
A.IgE-mediated (type I) hypersensitivity reactions are characterized by mast cell and basophil release of
histamine and other vasoactive compounds after exposure to an allergen. Examples of type I
hypersensitivity reactions include allergic rhinoconjunctivitis, asthma, and anaphylaxis.
Immune-complex-mediated (type III) hypersensitivity reactions are characterized by deposition of
antigen-antibody immune complexes that result in fixation and activation of complement. Examples
include serum sickness, systemic lupus erythematosus, and rheumatoid arthritis
Fungal infections such as tinea corporis can also present with circular, scaly patches, but typically have a
central clearing and an edge of advancing scale. The anatomic location of the rash in this patient (in an
area of likely contact to metals) further makes allergic contact dermatitis more likely
Deficiency of filaggrin, an epidermal protein that acts to link keratin fibers in epithelial cells, is associated
with disorders of dry skin including atopic dermatitis. Atopic dermatitis can present with itchy, scaly
plaques but are typically localized in the flexural areas in adults.
A 40-year-old man with history of HIV infection presents to the clinic with a red, flaky, oily rash around
his scalp, face, nose, and ears. He has tried low-dose topical steroids, which have not helped. He would
like stronger therapy for his rash.
What medication would be appropriate for this condition? - (correct Answer) - This condition is
Seborrheic Dermatitis
Since he has HIV and is immunocomproised and you've tried low-dose topical steriod, you could then try
a
topical antifungals (e.g., ketoconazole or selenium sulfide)
if he still has systemic therapies for severe or resistant disease:
- oral antifungals (e.g., ketoconazole)
- oral steroids
A 20-year-old student presents to the school's health clinic complaining of a scaly rash on his trunk. He
recalls having a mild fever and headaches a few weeks prior, but did not think much of it. The lesions do
not itch. He loves to play tennis and spends a lot of time outdoors and wear proper attire during
