Pseudolymphoma in Adult
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Synopsis

Pseudolymphoma (cutaneous lymphoid hyperplasia) is a benign inflammatory response that histologically and often clinically mimics cutaneous lymphoma. Both T-cell and B-cell forms of pseudolymphoma may be seen. Pseudolymphoma is characterized by dense lymphoid infiltrates of the skin, which may be focal or diffuse.
Triggers include insect bites or stings, which cause local reactions, or anticonvulsant drugs, which can cause widespread eruptions. Other causes include a broad range of non-anticonvulsant drugs (antihypertensives, lipid lowering agents, and antidepressants, among others), tattoo dyes, trauma, vaccinations, contact dermatitis, folliculitis, and infections (such as varicella, molluscum contagiosum, human immunodeficiency virus [HIV], or Lyme disease). Pseudolymphoma may be seen after scabies infection, particularly in children. Medication-related reactions may include fever, lymphadenopathy, and an erythematous skin eruption. Malaise, arthralgia, hepatosplenomegaly, eosinophilia, and abnormal liver function tests can also be present in medication-related cases.
While pseudolymphoma may occur at any age, it is most commonly seen in early adulthood.
Triggers include insect bites or stings, which cause local reactions, or anticonvulsant drugs, which can cause widespread eruptions. Other causes include a broad range of non-anticonvulsant drugs (antihypertensives, lipid lowering agents, and antidepressants, among others), tattoo dyes, trauma, vaccinations, contact dermatitis, folliculitis, and infections (such as varicella, molluscum contagiosum, human immunodeficiency virus [HIV], or Lyme disease). Pseudolymphoma may be seen after scabies infection, particularly in children. Medication-related reactions may include fever, lymphadenopathy, and an erythematous skin eruption. Malaise, arthralgia, hepatosplenomegaly, eosinophilia, and abnormal liver function tests can also be present in medication-related cases.
While pseudolymphoma may occur at any age, it is most commonly seen in early adulthood.
Codes
ICD10CM:
L98.8 – Other specified disorders of the skin and subcutaneous tissue
SNOMEDCT:
19750001 – Pseudolymphoma
L98.8 – Other specified disorders of the skin and subcutaneous tissue
SNOMEDCT:
19750001 – Pseudolymphoma
Look For
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Diagnostic Pearls
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Differential Diagnosis & Pitfalls
- Insect bite – Can be multiple.
- Fixed drug reaction
- Mycosis fungoides
- Cutaneous B-cell lymphoma
- Non-Hodgkin lymphoma
- Lymphocytic infiltrate of Jessner
- Sarcoidosis
- Scar
- Nodular scabies / scabies (pediatric) – Extremely pruritic.
- Lymphomatoid papulosis – Some of the papules are crusted with necrotic centers.
- Lymphomatoid granulomatosis
- Actinic reticuloid (see chronic actinic dermatitis)
- Follicular mucinosis
- Tumid lupus
- Syphilis
- Sweet syndrome
Best Tests
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Management Pearls
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Therapy
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Drug Reaction Data
Below is a list of drugs with literature evidence indicating an adverse association with this diagnosis. The list is continually updated through ongoing research and new medication approvals. Click on Citations to sort by number of citations or click on Medication to sort the medications alphabetically.
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References
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Last Reviewed:02/06/2018
Last Updated:03/20/2023
Last Updated:03/20/2023