Illustration of skin affected by lichenoid and pigmented drug eruption.

Acetazolamide and Skin Reactions: What You Need to Know

Soraya Malik in Health & Wellness December 2025 • 4 min read.

"A rare case highlights a potential link between acetazolamide, a common medication, and unique skin eruptions. Learn about symptoms, diagnosis, and implications."

Allergic and adverse reactions to sulfonamide medications are relatively common. While acetazolamide, a type of sulfonamide, is generally well-tolerated, it can occasionally lead to cutaneous adverse drug reactions (CADRs). These reactions can manifest in various ways, including maculopapular exanthemas, acute generalized exanthematous pustulosis (AGEP), and Stevens-Johnson syndrome.

This article reports a unique case of a lichenoid and pigmented drug eruption triggered by oral acetazolamide, confirmed through a lichenoid patch test. This is the first documented case of its kind, offering valuable insights into the potential dermatological side effects of this medication.

The case involves a 76-year-old patient who developed a pruriginous maculopapular rash after being prescribed oral acetazolamide to prevent vitreous loss during cataract surgery. The rash initially appeared in the large folds of the skin, specifically in the submammary, inguinal, and axillary areas, without any mucosal involvement.

Unusual Symptoms and Diagnosis

Illustration of skin affected by lichenoid and pigmented drug eruption.

The patient's condition evolved rapidly. Although pustules weren't initially observed, the skin lesions progressed to a fine desquamation, a characteristic sign observed during the healing phase of AGEP. Clinical examination revealed the patient was afebrile but presented with bilateral axillary lymphadenopathy and mild facial edema.

Laboratory investigations revealed hyperleukocytosis (elevated white blood cell count) and an increased eosinophil count, suggesting an allergic reaction. An initial skin biopsy revealed changes in the epidermis and a band-like infiltrate of lymphocytes in the upper dermis, consistent with a lichenoid pattern. However, eosinophils were absent in this initial biopsy.

Lichenoid Pattern: Characterized by a band-like infiltrate of lymphocytes in the upper dermis.
Hyperpigmentation: Development of hyperpigmented skin patches in previously affected areas.
Patch Test Confirmation: Positive patch tests for acetazolamide confirmed the diagnosis.

A follow-up examination two months later revealed hyperpigmented skin patches in the previously affected areas, extending to the face, upper and lower limbs, and abdomen. A subsequent skin biopsy of the pigmented lesions showed a more pronounced lichenoid pattern associated with dermal melanophages (cells that contain melanin). Drug patch tests were conducted, and all acetazolamide preparations tested positive, both on healthy skin and on the residual pigmented skin lesion. Interestingly, the patch tests also presented an hyperpigmented evolution.

Implications and Further Considerations

This case underscores the importance of considering acetazolamide as a potential cause of lichenoid and pigmented drug eruptions, even though such reactions are rare. The positive patch test results emphasize the value of patch testing in assessing drug imputability and confirming the diagnosis.

While the initial presentation resembled AGEP, the progression to hyperpigmented skin and the lichenoid pattern observed in biopsies differentiated it from typical AGEP cases. This highlights the importance of careful clinical and histopathological evaluation in diagnosing unusual drug reactions.

This case expands the spectrum of known cutaneous side effects associated with acetazolamide and emphasizes the need for clinicians to be aware of these potential reactions. Further research is needed to understand the underlying mechanisms and risk factors associated with acetazolamide-induced lichenoid and pigmented drug eruptions.

About this Article -

This article was crafted using a human-AI hybrid and collaborative approach. AI assisted our team with initial drafting, research insights, identifying key questions, and image generation. Our human editors guided topic selection, defined the angle, structured the content, ensured factual accuracy and relevance, refined the tone, and conducted thorough editing to deliver helpful, high-quality information.See our About page for more information.

This article is based on research published under:

DOI-LINK: 10.1016/j.jaip.2017.07.005, Alternate LINK

Title: A Case Of Lichenoid And Pigmented Drug Eruption To Acetazolamide Confirmed By A Lichenoid Patch Test

Subject: Immunology and Allergy

Journal: The Journal of Allergy and Clinical Immunology: In Practice

Publisher: Elsevier BV

Authors: Laure Dequidt, Brigitte Milpied, Annick Chauvel, Julien Seneschal, Alain Taieb, Anne-Sophie Darrigade

Published: 2018-01-01

Everything You Need To Know

What are the different types of skin reactions that can occur from taking acetazolamide?

Acetazolamide, while generally well-tolerated, can sometimes cause cutaneous adverse drug reactions (CADRs). These reactions can appear as maculopapular exanthemas, acute generalized exanthematous pustulosis (AGEP), or Stevens-Johnson syndrome. A rare reaction is a lichenoid and pigmented drug eruption, as highlighted by a unique case where a patient developed a pruriginous maculopapular rash that later showed hyperpigmentation. While the more common reactions are well-documented, the specific case of lichenoid and pigmented eruption is notable due to its rarity and diagnostic challenges.

How was the lichenoid and pigmented drug eruption from acetazolamide confirmed in the reported case?

The lichenoid and pigmented drug eruption was confirmed through several diagnostic steps. Initially, a skin biopsy revealed a lichenoid pattern with a band-like infiltrate of lymphocytes. Later, drug patch tests were conducted using various acetazolamide preparations, and all tests came back positive, both on healthy skin and on the residual pigmented skin lesion. The patch tests also showed an hyperpigmented evolution, further confirming the diagnosis. This multi-faceted approach, combining biopsy results and patch test confirmation, was crucial in establishing acetazolamide as the cause of the unusual skin reaction.

What is a lichenoid pattern in the context of skin reactions, and why is it important for diagnosis?

A lichenoid pattern is characterized by a band-like infiltrate of lymphocytes in the upper dermis of the skin. This pattern is significant because it indicates a specific type of inflammatory response often associated with certain drug reactions or skin conditions. In the case of acetazolamide-induced skin eruptions, identifying a lichenoid pattern in a skin biopsy is an important clue, though not definitive on its own. The presence of this pattern, combined with other clinical findings and positive patch tests, helps to confirm the diagnosis and differentiate it from other types of skin reactions. Further biopsy may reveal dermal melanophages too.

What should doctors consider regarding acetazolamide and potential skin reactions?

Doctors should be aware that acetazolamide, though generally well-tolerated, has the potential to cause rare lichenoid and pigmented drug eruptions, even if such reactions are uncommon. If a patient presents with a rash, particularly in skin folds or areas previously affected, and is taking acetazolamide, this medication should be considered as a possible cause. Performing drug patch tests can be valuable in confirming the diagnosis. Early recognition and appropriate management can help to prevent the progression of the skin reaction and improve patient outcomes.

What are melanophages, and what do they indicate in the context of pigmented skin lesions related to acetazolamide?

Melanophages are cells that contain melanin, which is the pigment responsible for skin color. In the context of pigmented skin lesions related to acetazolamide, the presence of dermal melanophages indicates that there has been pigmentary incontinence, where melanin is released from melanocytes (pigment-producing cells) and then engulfed by macrophages (immune cells). This finding, along with a lichenoid pattern, suggests a specific type of drug-induced reaction where the inflammation has led to pigmentary changes in the skin. The appearance of melanophages in a skin biopsy, especially in previously inflamed areas, supports the diagnosis of a pigmented drug eruption caused by acetazolamide.