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For more than 2 years, this 36-year-old woman has had a slightly itchy rash that waxes and wanes on her posterior neck. She has consulted several primary care providers and received multiple diagnoses, the most consistent of which has been fungal infection. However, despite use of a variety of antifungal creams (nystatin, clotrimazole, and combination clotrimazole/betamethasone), a 1-month course of oral terbinafine, and OTC tolnaftate, no improvement has occurred.
The patient asserts that she is otherwise in good health, with no joint pain or fever and no history of recent health crises. Family history is free of dermatologic complaints except for psoriasis in her father.
EXAMINATION
A pink plaque with white, fairly adherent scale covers most of the patient’s posterior neck/upper midline back. When a 3-mm section of scaling is peeled away, 2 tiny dots of pinpoint bleeding are immediately noted.
The rest of her scalp is free of any such changes, as are her elbows and knees. But a similar rash is seen in the upper intergluteal area, and 3 of 10 fingernails are mildly pitted.
What’s the diagnosis?
DISCUSSION
Psoriasis vulgaris (common psoriasis) affects around 3% of the white population in this country. That incidence almost doubles in northern Europe and Scandinavia.
Psoriasis is so common that you should expect to see it regularly; the important question is not “Will you see it?” but rather “Will you know it when you see it?” Sometimes the various clinical elements of psoriasis must be sought, and those dots connected, as this case demonstrates effectively.
For one thing, the nape of the neck is commonly affected, especially in women. It is pure speculation, but one imagines that the heat and sweat associated with longer hair might contribute to this predilection.
The pink color, whitish scale, and pinpoint bleeding (termed the Auspitz sign) all corroborate the diagnosis, as does the positive family history and nail pitting. The intergluteal involvement was the icing on the cake; this is seen in only 2 common conditions: psoriasis and seborrhea.
The lesson? Even though psoriasis is supposed to appear on elbows, knees, and other extensor surfaces, sometimes it breaks the rules. The posterior neck was the primary area of involvement in this case, but sometimes psoriasis is completely confined to the scalp or the palms. And, of course, there are different types of psoriasis, some of which bear scant resemblance to psoriasis vulgaris. That’s where biopsies and/or referrals prove to be useful.
It is true that this patient’s rash could have had a fungal origin. When in doubt, however, a punch or shave biopsy would most likely settle the matter, since the histologic picture is usually pathognomic.
TAKE-HOME LEARNING POINTS
- Psoriasis is often be easy to diagnose—but just as often, it takes a bit of detective work.
- This “investigation” consists of looking for and asking about findings that could corroborate the diagnosis.
- The morphology of the neck lesion, as well as the Auspitz sign, nail pitting, intergluteal involvement, and family history in this case all served quite well to establish the diagnosis of psoriasis.
- It is helpful to remember how utterly common psoriasis is, affecting around 10,000,000 Americans.
For more than 2 years, this 36-year-old woman has had a slightly itchy rash that waxes and wanes on her posterior neck. She has consulted several primary care providers and received multiple diagnoses, the most consistent of which has been fungal infection. However, despite use of a variety of antifungal creams (nystatin, clotrimazole, and combination clotrimazole/betamethasone), a 1-month course of oral terbinafine, and OTC tolnaftate, no improvement has occurred.
The patient asserts that she is otherwise in good health, with no joint pain or fever and no history of recent health crises. Family history is free of dermatologic complaints except for psoriasis in her father.
EXAMINATION
A pink plaque with white, fairly adherent scale covers most of the patient’s posterior neck/upper midline back. When a 3-mm section of scaling is peeled away, 2 tiny dots of pinpoint bleeding are immediately noted.
The rest of her scalp is free of any such changes, as are her elbows and knees. But a similar rash is seen in the upper intergluteal area, and 3 of 10 fingernails are mildly pitted.
What’s the diagnosis?
DISCUSSION
Psoriasis vulgaris (common psoriasis) affects around 3% of the white population in this country. That incidence almost doubles in northern Europe and Scandinavia.
Psoriasis is so common that you should expect to see it regularly; the important question is not “Will you see it?” but rather “Will you know it when you see it?” Sometimes the various clinical elements of psoriasis must be sought, and those dots connected, as this case demonstrates effectively.
For one thing, the nape of the neck is commonly affected, especially in women. It is pure speculation, but one imagines that the heat and sweat associated with longer hair might contribute to this predilection.
The pink color, whitish scale, and pinpoint bleeding (termed the Auspitz sign) all corroborate the diagnosis, as does the positive family history and nail pitting. The intergluteal involvement was the icing on the cake; this is seen in only 2 common conditions: psoriasis and seborrhea.
The lesson? Even though psoriasis is supposed to appear on elbows, knees, and other extensor surfaces, sometimes it breaks the rules. The posterior neck was the primary area of involvement in this case, but sometimes psoriasis is completely confined to the scalp or the palms. And, of course, there are different types of psoriasis, some of which bear scant resemblance to psoriasis vulgaris. That’s where biopsies and/or referrals prove to be useful.
It is true that this patient’s rash could have had a fungal origin. When in doubt, however, a punch or shave biopsy would most likely settle the matter, since the histologic picture is usually pathognomic.
TAKE-HOME LEARNING POINTS
- Psoriasis is often be easy to diagnose—but just as often, it takes a bit of detective work.
- This “investigation” consists of looking for and asking about findings that could corroborate the diagnosis.
- The morphology of the neck lesion, as well as the Auspitz sign, nail pitting, intergluteal involvement, and family history in this case all served quite well to establish the diagnosis of psoriasis.
- It is helpful to remember how utterly common psoriasis is, affecting around 10,000,000 Americans.
For more than 2 years, this 36-year-old woman has had a slightly itchy rash that waxes and wanes on her posterior neck. She has consulted several primary care providers and received multiple diagnoses, the most consistent of which has been fungal infection. However, despite use of a variety of antifungal creams (nystatin, clotrimazole, and combination clotrimazole/betamethasone), a 1-month course of oral terbinafine, and OTC tolnaftate, no improvement has occurred.
The patient asserts that she is otherwise in good health, with no joint pain or fever and no history of recent health crises. Family history is free of dermatologic complaints except for psoriasis in her father.
EXAMINATION
A pink plaque with white, fairly adherent scale covers most of the patient’s posterior neck/upper midline back. When a 3-mm section of scaling is peeled away, 2 tiny dots of pinpoint bleeding are immediately noted.
The rest of her scalp is free of any such changes, as are her elbows and knees. But a similar rash is seen in the upper intergluteal area, and 3 of 10 fingernails are mildly pitted.
What’s the diagnosis?
DISCUSSION
Psoriasis vulgaris (common psoriasis) affects around 3% of the white population in this country. That incidence almost doubles in northern Europe and Scandinavia.
Psoriasis is so common that you should expect to see it regularly; the important question is not “Will you see it?” but rather “Will you know it when you see it?” Sometimes the various clinical elements of psoriasis must be sought, and those dots connected, as this case demonstrates effectively.
For one thing, the nape of the neck is commonly affected, especially in women. It is pure speculation, but one imagines that the heat and sweat associated with longer hair might contribute to this predilection.
The pink color, whitish scale, and pinpoint bleeding (termed the Auspitz sign) all corroborate the diagnosis, as does the positive family history and nail pitting. The intergluteal involvement was the icing on the cake; this is seen in only 2 common conditions: psoriasis and seborrhea.
The lesson? Even though psoriasis is supposed to appear on elbows, knees, and other extensor surfaces, sometimes it breaks the rules. The posterior neck was the primary area of involvement in this case, but sometimes psoriasis is completely confined to the scalp or the palms. And, of course, there are different types of psoriasis, some of which bear scant resemblance to psoriasis vulgaris. That’s where biopsies and/or referrals prove to be useful.
It is true that this patient’s rash could have had a fungal origin. When in doubt, however, a punch or shave biopsy would most likely settle the matter, since the histologic picture is usually pathognomic.
TAKE-HOME LEARNING POINTS
- Psoriasis is often be easy to diagnose—but just as often, it takes a bit of detective work.
- This “investigation” consists of looking for and asking about findings that could corroborate the diagnosis.
- The morphology of the neck lesion, as well as the Auspitz sign, nail pitting, intergluteal involvement, and family history in this case all served quite well to establish the diagnosis of psoriasis.
- It is helpful to remember how utterly common psoriasis is, affecting around 10,000,000 Americans.
