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ANSWER
The correct answer is koebnerization of pre-existing psoriasis (choice “c”).
DISCUSSION
Tattoos have been known to cause bacterial infection (choice “a”), but this was unlikely given the diffuse nature of the rash and the lack of pain or adenopathy. Allergic reactions to tattoo dyes (choice “b”) are certainly common, but usually red or yellow dyes—which were not used for this tattoo—provoke the worst reactions. Furthermore, itching would have been a more prominent feature of the patient's complaint. Had it been fungal infection (choice “d”), the steroid cream would have made it worse.
One possibility remained: the so-called isomorphic phenomenon (otherwise known as koebnerization). First described by Heinrich Koebner in the mid-19th century, koebnerization is characterized by the appearance of psoriasis in traumatized skin such as surgical wounds, abrasions, burns, or even tattoos. Several other conditions also exhibit this same linear response to trauma, including warts, molluscum, and lichen planus.
To test for this diagnosis, corroborative findings of psoriasis were sought and found in the patient’s nails. His history of rashes on the knees and elbows also contributed to establishing the diagnosis. Moreover, his complaint of arthritis was quite suggestive of psoriatic arthropathy, which afflicts about 25% of patients with psoriasis and has little to do with the severity of the skin disease itself. Once the diagnosis became more apparent, the patient recalled a family history of psoriasis. Had any question remained, a biopsy could remove doubt.
TREATMENT
For the patient, twice-daily application of a stronger steroid cream (augmented betamethasone) was prescribed. Though this quickly cleared the koebnerizing psoriasis, it is likely we haven’t seen the last of this disease.
ANSWER
The correct answer is koebnerization of pre-existing psoriasis (choice “c”).
DISCUSSION
Tattoos have been known to cause bacterial infection (choice “a”), but this was unlikely given the diffuse nature of the rash and the lack of pain or adenopathy. Allergic reactions to tattoo dyes (choice “b”) are certainly common, but usually red or yellow dyes—which were not used for this tattoo—provoke the worst reactions. Furthermore, itching would have been a more prominent feature of the patient's complaint. Had it been fungal infection (choice “d”), the steroid cream would have made it worse.
One possibility remained: the so-called isomorphic phenomenon (otherwise known as koebnerization). First described by Heinrich Koebner in the mid-19th century, koebnerization is characterized by the appearance of psoriasis in traumatized skin such as surgical wounds, abrasions, burns, or even tattoos. Several other conditions also exhibit this same linear response to trauma, including warts, molluscum, and lichen planus.
To test for this diagnosis, corroborative findings of psoriasis were sought and found in the patient’s nails. His history of rashes on the knees and elbows also contributed to establishing the diagnosis. Moreover, his complaint of arthritis was quite suggestive of psoriatic arthropathy, which afflicts about 25% of patients with psoriasis and has little to do with the severity of the skin disease itself. Once the diagnosis became more apparent, the patient recalled a family history of psoriasis. Had any question remained, a biopsy could remove doubt.
TREATMENT
For the patient, twice-daily application of a stronger steroid cream (augmented betamethasone) was prescribed. Though this quickly cleared the koebnerizing psoriasis, it is likely we haven’t seen the last of this disease.
ANSWER
The correct answer is koebnerization of pre-existing psoriasis (choice “c”).
DISCUSSION
Tattoos have been known to cause bacterial infection (choice “a”), but this was unlikely given the diffuse nature of the rash and the lack of pain or adenopathy. Allergic reactions to tattoo dyes (choice “b”) are certainly common, but usually red or yellow dyes—which were not used for this tattoo—provoke the worst reactions. Furthermore, itching would have been a more prominent feature of the patient's complaint. Had it been fungal infection (choice “d”), the steroid cream would have made it worse.
One possibility remained: the so-called isomorphic phenomenon (otherwise known as koebnerization). First described by Heinrich Koebner in the mid-19th century, koebnerization is characterized by the appearance of psoriasis in traumatized skin such as surgical wounds, abrasions, burns, or even tattoos. Several other conditions also exhibit this same linear response to trauma, including warts, molluscum, and lichen planus.
To test for this diagnosis, corroborative findings of psoriasis were sought and found in the patient’s nails. His history of rashes on the knees and elbows also contributed to establishing the diagnosis. Moreover, his complaint of arthritis was quite suggestive of psoriatic arthropathy, which afflicts about 25% of patients with psoriasis and has little to do with the severity of the skin disease itself. Once the diagnosis became more apparent, the patient recalled a family history of psoriasis. Had any question remained, a biopsy could remove doubt.
TREATMENT
For the patient, twice-daily application of a stronger steroid cream (augmented betamethasone) was prescribed. Though this quickly cleared the koebnerizing psoriasis, it is likely we haven’t seen the last of this disease.
Weeks ago, a 43-year-old man received a birthday tattoo of his choice: a geometric pattern etched in blue ink on his wrist. Unfortunately, a rash began to develop within the lines of the tattoo. The rash itches, but its appearance is of greater concern to the patient. He’s gotten some relief from topical creams, although the rash quickly returns with cessation of treatment.
Past medical history is notable for arthritis affecting his left elbow and right heel. He also has intermittent rashes that manifest on his elbows and knees, but these are partially relieved by a steroid cream (triamcinolone 0.1%).
His tattoo is located on the extensor right wrist. The affected areas show a brisk, red, inflammatory response, which—in several locations—is also scaly. There is no tenderness or induration on palpation of the rash and no palpable adenopathy in local nodal locations (epitrochlear and axillary). Elsewhere, 5 of his 10 fingernails demonstrate pitting; 2 show onycholysis and oil spotting. His scalp, knees, and elbows are free of any notable changes.
