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A 10-year-old girl is seen in dermatology for evaluation of dry skin. She reports few if any symptoms but expresses frustration at her inability to curb the problem; she’s tried several different moisturizers to no avail.
Additional history-taking reveals that she’s had patches of dry skin since age 4; these have appeared and disappeared on her arms, legs, and neck. None has ever been problematic enough to require medical attention.
But recently, a dry patch manifested on the patient’s forearm that her primary care provider diagnosed as fungal infection. Unfortunately, the prescribed antifungal creams (terbinafine and clotrimazole) had no positive impact on the situation.
The patient and her mother deny any family history of skin disease.
EXAMINATION
The scaly, annular plaque on the patient’s extensor left forearm is distinctly salmon-pink, with a tenacious white scale. Elsewhere, there are scaly areas in both post-auricular sulci. There are no significant changes to the skin on the patient’s knees, elbows, or scalp. Several tiny pits are observed on her fingernails.
What is the diagnosis?
DISCUSSION
It would be difficult to imagine a more clear-cut case of psoriasis: not only manifesting with a classic plaque on the left extensor forearm but also with corroboratory stigmata behind the ears and classic fingernail pits. Then why, you might ask, was the diagnosis missed?
Psoriasis has a classic look: annular borders, salmon-pink color, and thick, tenacious scale. Distribution matters, since the condition tends to manifest in specific areas, particularly the extensor portions of extremities. It’s helpful to know that psoriasis affects almost 3% of the white population in the United States, meaning that you will see it with considerable frequency. It would also help if you knew the diagnosis can be corroborated by identification of other, lesser known features.
But if you’re unaware of these facts, you won’t look for these things—and if you don’t look specifically for them, you won’t see them. Then, to add insult to injury, when you consult your bag of “diseases that present with annular borders and scaly surfaces,” you’ll find one item in your differential: fungal infection. When antifungal medications don’t work, you’ll find yourself stuck, because you simply don’t have any other diagnoses to consider.
I’ve known internists who have practiced for more than 25 years and still make this diagnostic mistake. So it’s not a matter of lack of intelligence. They simply do not invest the time to expand their knowledge of dermatologic conditions.
My job was to break the news to the patient and her mother about the diagnosis and, perhaps more importantly, her prognosis. The only good news is that the patient is living in the golden age of psoriasis treatment; if her condition flares, and even if she eventually develops psoriatic arthritis (as do almost 25% of psoriasis patients), we have terrific treatment for it.
I prescribed topical fluocinonide 0.05% ointment (for bid application) to address her plaque and scheduled a follow-up visit for one month later. Before she left, though, I had to address her most pressing question: “Why did my doctor say this was a fungal infection?” Good question indeed.
TAKE-HOME LEARNING POINTS
• Psoriasis is quite commonly seen in primary care, since it affects almost 3% of the white population.
• Psoriasis is the quintessential papulosquamous disorder, manifesting with salmon-pink scaly patches on extensor extremities, behind ears, and/or in scalp.
• The diagnosis may be corroborated by identification of pits in the fingernails (25% of cases).
• Confirmation of the diagnosis can be made by punch biopsy, which usually shows characteristic changes.
• The overarching learning point: Your differential for “round and scaly” needs more than one item in it.
A 10-year-old girl is seen in dermatology for evaluation of dry skin. She reports few if any symptoms but expresses frustration at her inability to curb the problem; she’s tried several different moisturizers to no avail.
Additional history-taking reveals that she’s had patches of dry skin since age 4; these have appeared and disappeared on her arms, legs, and neck. None has ever been problematic enough to require medical attention.
But recently, a dry patch manifested on the patient’s forearm that her primary care provider diagnosed as fungal infection. Unfortunately, the prescribed antifungal creams (terbinafine and clotrimazole) had no positive impact on the situation.
The patient and her mother deny any family history of skin disease.
EXAMINATION
The scaly, annular plaque on the patient’s extensor left forearm is distinctly salmon-pink, with a tenacious white scale. Elsewhere, there are scaly areas in both post-auricular sulci. There are no significant changes to the skin on the patient’s knees, elbows, or scalp. Several tiny pits are observed on her fingernails.
What is the diagnosis?
DISCUSSION
It would be difficult to imagine a more clear-cut case of psoriasis: not only manifesting with a classic plaque on the left extensor forearm but also with corroboratory stigmata behind the ears and classic fingernail pits. Then why, you might ask, was the diagnosis missed?
Psoriasis has a classic look: annular borders, salmon-pink color, and thick, tenacious scale. Distribution matters, since the condition tends to manifest in specific areas, particularly the extensor portions of extremities. It’s helpful to know that psoriasis affects almost 3% of the white population in the United States, meaning that you will see it with considerable frequency. It would also help if you knew the diagnosis can be corroborated by identification of other, lesser known features.
But if you’re unaware of these facts, you won’t look for these things—and if you don’t look specifically for them, you won’t see them. Then, to add insult to injury, when you consult your bag of “diseases that present with annular borders and scaly surfaces,” you’ll find one item in your differential: fungal infection. When antifungal medications don’t work, you’ll find yourself stuck, because you simply don’t have any other diagnoses to consider.
I’ve known internists who have practiced for more than 25 years and still make this diagnostic mistake. So it’s not a matter of lack of intelligence. They simply do not invest the time to expand their knowledge of dermatologic conditions.
My job was to break the news to the patient and her mother about the diagnosis and, perhaps more importantly, her prognosis. The only good news is that the patient is living in the golden age of psoriasis treatment; if her condition flares, and even if she eventually develops psoriatic arthritis (as do almost 25% of psoriasis patients), we have terrific treatment for it.
I prescribed topical fluocinonide 0.05% ointment (for bid application) to address her plaque and scheduled a follow-up visit for one month later. Before she left, though, I had to address her most pressing question: “Why did my doctor say this was a fungal infection?” Good question indeed.
TAKE-HOME LEARNING POINTS
• Psoriasis is quite commonly seen in primary care, since it affects almost 3% of the white population.
• Psoriasis is the quintessential papulosquamous disorder, manifesting with salmon-pink scaly patches on extensor extremities, behind ears, and/or in scalp.
• The diagnosis may be corroborated by identification of pits in the fingernails (25% of cases).
• Confirmation of the diagnosis can be made by punch biopsy, which usually shows characteristic changes.
• The overarching learning point: Your differential for “round and scaly” needs more than one item in it.
A 10-year-old girl is seen in dermatology for evaluation of dry skin. She reports few if any symptoms but expresses frustration at her inability to curb the problem; she’s tried several different moisturizers to no avail.
Additional history-taking reveals that she’s had patches of dry skin since age 4; these have appeared and disappeared on her arms, legs, and neck. None has ever been problematic enough to require medical attention.
But recently, a dry patch manifested on the patient’s forearm that her primary care provider diagnosed as fungal infection. Unfortunately, the prescribed antifungal creams (terbinafine and clotrimazole) had no positive impact on the situation.
The patient and her mother deny any family history of skin disease.
EXAMINATION
The scaly, annular plaque on the patient’s extensor left forearm is distinctly salmon-pink, with a tenacious white scale. Elsewhere, there are scaly areas in both post-auricular sulci. There are no significant changes to the skin on the patient’s knees, elbows, or scalp. Several tiny pits are observed on her fingernails.
What is the diagnosis?
DISCUSSION
It would be difficult to imagine a more clear-cut case of psoriasis: not only manifesting with a classic plaque on the left extensor forearm but also with corroboratory stigmata behind the ears and classic fingernail pits. Then why, you might ask, was the diagnosis missed?
Psoriasis has a classic look: annular borders, salmon-pink color, and thick, tenacious scale. Distribution matters, since the condition tends to manifest in specific areas, particularly the extensor portions of extremities. It’s helpful to know that psoriasis affects almost 3% of the white population in the United States, meaning that you will see it with considerable frequency. It would also help if you knew the diagnosis can be corroborated by identification of other, lesser known features.
But if you’re unaware of these facts, you won’t look for these things—and if you don’t look specifically for them, you won’t see them. Then, to add insult to injury, when you consult your bag of “diseases that present with annular borders and scaly surfaces,” you’ll find one item in your differential: fungal infection. When antifungal medications don’t work, you’ll find yourself stuck, because you simply don’t have any other diagnoses to consider.
I’ve known internists who have practiced for more than 25 years and still make this diagnostic mistake. So it’s not a matter of lack of intelligence. They simply do not invest the time to expand their knowledge of dermatologic conditions.
My job was to break the news to the patient and her mother about the diagnosis and, perhaps more importantly, her prognosis. The only good news is that the patient is living in the golden age of psoriasis treatment; if her condition flares, and even if she eventually develops psoriatic arthritis (as do almost 25% of psoriasis patients), we have terrific treatment for it.
I prescribed topical fluocinonide 0.05% ointment (for bid application) to address her plaque and scheduled a follow-up visit for one month later. Before she left, though, I had to address her most pressing question: “Why did my doctor say this was a fungal infection?” Good question indeed.
TAKE-HOME LEARNING POINTS
• Psoriasis is quite commonly seen in primary care, since it affects almost 3% of the white population.
• Psoriasis is the quintessential papulosquamous disorder, manifesting with salmon-pink scaly patches on extensor extremities, behind ears, and/or in scalp.
• The diagnosis may be corroborated by identification of pits in the fingernails (25% of cases).
• Confirmation of the diagnosis can be made by punch biopsy, which usually shows characteristic changes.
• The overarching learning point: Your differential for “round and scaly” needs more than one item in it.
