Understanding What Are the Side Effects of Acetazolamide on the Skin?

October 10, 2025 •

3 min read

Up to 50% of patients taking acetazolamide may experience paresthesia, a common skin side effect involving numbness and tingling. Beyond this frequent sensory change, understanding what are the side effects of acetazolamide on the skin is critical, as reactions can range from increased sun sensitivity to rare but life-threatening severe allergic reactions.

Quick Summary

Acetazolamide can cause a variety of skin effects, most commonly paresthesia (tingling) and increased sun sensitivity (photosensitivity). While less frequent, severe reactions such as Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN) have been reported and require immediate medical attention.

Key Points

Paresthesia is a very common side effect: Up to 50% of patients experience tingling or numbness, often in the extremities, due to electrolyte changes.
Photosensitivity increases sunburn risk: Acetazolamide can make your skin more sensitive to sunlight, requiring increased use of sunscreen and protective clothing.
Severe cutaneous reactions (SCARs) are rare but serious: Life-threatening conditions like Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN) can occur, presenting with flu-like symptoms and severe blistering.
Sulfa allergy increases reaction risk: As a sulfonamide, acetazolamide carries a higher risk of allergic reactions, including rashes and hives, for individuals with a history of sulfa allergies.
Genetic factors play a role in severe reactions: Some Asian populations, particularly those with the HLA-B59 genetic marker, may have an increased risk of developing SJS/TEN.
Report severe symptoms immediately: If a fever, rash, or blistering occurs, stop the medication and seek emergency medical attention.

Common Skin Side Effects: Paresthesia and Photosensitivity

For many patients, the most notable skin-related effect of acetazolamide is a change in sensation rather than a visible rash. As a sulfonamide derivative and carbonic anhydrase inhibitor, the drug's impact on electrolyte balance and pH levels can affect nerve function.

Paresthesia: Tingling and Numbness

Paresthesia is one of the most frequently reported side effects of acetazolamide, with studies indicating it may occur in up to half of patients. This condition is characterized by abnormal skin sensations, which can include:

Tingling or a "pins and needles" sensation
Burning feelings
Numbness
Sensations commonly localized to the hands, feet, and area around the mouth

This effect is dose-dependent and typically not a health threat, often resolving with a dosage reduction. Paresthesia is thought to occur due to electrolyte disturbances affecting the nervous system.

Photosensitivity: Increased Sun Sensitivity

Acetazolamide can make the skin more sensitive to light from the sun, sunlamps, and tanning beds, a condition known as photosensitivity. This can result in severe sunburns, rashes, and blistering upon sun exposure.

To manage photosensitivity, patients should:

Avoid prolonged sun exposure
Wear protective clothing, such as long sleeves and hats
Apply broad-spectrum sunscreen with a high SPF

Allergic and Hypersensitivity Reactions

Because acetazolamide is a sulfonamide-based drug, it can trigger various allergic reactions, from mild to severe. Individuals with a history of sulfa allergies are often at an increased risk.

Mild to Moderate Allergic Reactions

Skin rash
Hives (urticaria)
Itching
Swelling of the face, lips, or tongue

Any sign of an allergic reaction should be reported to a healthcare provider. While milder cases can be managed, more severe symptoms, particularly swelling and breathing difficulties, require immediate medical attention.

Severe Cutaneous Adverse Reactions (SCARs)

SCARs are rare but life-threatening allergic reactions. Two of the most serious types reported in association with acetazolamide are Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN). These conditions involve widespread blistering and peeling of the skin and mucous membranes. SJS and TEN are often preceded by flu-like symptoms, including fever, sore throat, and body aches. Specific genetic predispositions, particularly the HLA-B59 marker in individuals of Japanese or Korean descent, have been linked to an increased risk of SJS/TEN when taking related medications.

Comparison of Acetazolamide Skin Side Effects


Characteristic	Paresthesia	Photosensitivity	Severe Cutaneous Adverse Reactions (SJS/TEN)
Incidence	Very Common (up to 50% of patients)	Infrequent to Rare (reported)	Very Rare (serious and potentially fatal)
Onset	Often early in treatment, may persist	Can develop after sun exposure	Weeks to months after starting medication
Mechanism	Electrolyte imbalances, effects on nerve function	Chemically induced increase in skin sensitivity to UV radiation	Idiosyncratic immune reaction, possibly linked to genetic markers (e.g., HLA-B59)
Symptoms	Tingling, numbness, burning, "pins and needles"	Severe sunburn, redness, swelling, blisters	Flu-like symptoms (fever, sore throat) followed by painful red or purple rash, blistering, and skin peeling
Management	Often resolves with dose adjustment	Sun avoidance, protective clothing, sunscreen	Immediate discontinuation of drug and emergency medical care

Less Common and Delayed Skin Issues

Other dermatologic reactions to acetazolamide may occur less frequently or develop over time.

General Skin Rash and Hives: Simple skin rashes or hives can occur as a form of general allergic reaction.
Erythema Multiforme: A rare but serious skin condition causing red, inflamed, target-like lesions on the skin.
Other Allergic Signs: Skin pain, sores in the mouth, and burning eyes can accompany other serious reactions.
Jaundice: In very rare cases, liver injury may occur, leading to yellowing of the skin or eyes.

These symptoms warrant prompt medical consultation, particularly if they appear alongside flu-like symptoms or other signs of systemic illness. For comprehensive information on potential side effects, consult with a healthcare professional or refer to reliable drug databases like the one on Drugs.com.

Conclusion

While acetazolamide is an effective medication for conditions like glaucoma and altitude sickness, it can cause a range of skin-related side effects. The most common are paresthesia and photosensitivity, which are generally manageable. However, it is essential to be aware of the signs of rare but severe allergic reactions, such as SJS and TEN, and to seek immediate medical help if these symptoms occur. Patients with a sulfa allergy or certain genetic markers should discuss their risks with their doctor before starting the medication. Open communication with your healthcare provider is key to safely managing any skin-related issues while on acetazolamide therapy.

Frequently Asked Questions

Paresthesia is very common, affecting up to 50% of patients taking acetazolamide. It is a frequent and often temporary sensory side effect that tends to resolve with dose reduction.

Photosensitivity is increased skin sensitivity to sunlight, sunlamps, and tanning beds. To manage it, you should avoid prolonged sun exposure, wear protective clothing, and use sunscreen with a high SPF.

Acetazolamide is a sulfonamide-based drug, which means individuals with a known sulfa allergy may be at a higher risk of developing an allergic reaction, such as a rash or hives.

Severe skin reactions often begin with fever and flu-like symptoms. A painful, spreading red or purple rash follows, which can blister and lead to skin peeling. Immediate medical help is required if these symptoms appear.

Common side effects like paresthesia can appear early in treatment, sometimes within days. Photosensitivity develops after sun exposure. Severe cutaneous reactions (SCARs), though rare, can develop weeks to months after starting the medication.

Yes, some patients may experience a general skin rash or hives as a less severe allergic reaction to the medication. Any new rash should be reported to your doctor.

Yes, though very rare, liver injury can occur, which may present as jaundice (yellowing of the skin or eyes). This is a serious side effect that requires immediate medical attention.