Can Valtrex cause acne? Investigating the Link Between Valacyclovir and Skin Side Effects

October 11, 2025 •

4 min read

According to clinical data, acne is listed as a common side effect of Valtrex (valacyclovir), affecting 1% to 10% of users. This raises the question: Can Valtrex cause acne? Understanding this potential link is crucial for patients experiencing new skin issues while on this antiviral medication.

Quick Summary

Valtrex (valacyclovir) can cause acne, though its occurrence varies. Clinical data indicates it is a known, though not frequent, side effect, often appearing alongside other skin issues like rashes. This article explores the likelihood, mechanisms, and management of drug-induced acne from valacyclovir.

Key Points

Possible Side Effect: Acne is a documented, though less common, side effect of Valtrex (valacyclovir) affecting 1-10% of users, as reported in clinical data.
Not True Acne Vulgaris: The skin condition is typically a drug-induced, acneiform eruption, which can be distinguished from common acne by its uniform appearance and lack of typical comedones.
Consult a Doctor: If you develop an acne-like rash, you should speak with your healthcare provider to confirm the cause and discuss management options.
Differentiate from Outbreaks: It's important to distinguish drug-induced skin issues from the blisters associated with a herpes outbreak or from a true allergic reaction.
Management is Possible: Depending on severity, drug-induced acne can be managed with topical treatments or by adjusting the medication, all under medical supervision.
Never Stop Abruptly: Do not stop taking Valtrex without a doctor's consultation, as this can increase the risk of the virus becoming resistant.

What is Valtrex (Valacyclovir)?

Valtrex is the brand name for the antiviral drug valacyclovir hydrochloride. It is primarily used to treat infections caused by certain herpes viruses, which include herpes simplex virus (HSV) and varicella zoster virus (VZV). In the body, valacyclovir is converted into acyclovir, the active antiviral agent that works by slowing the growth and spread of the herpes virus. It is prescribed for conditions such as cold sores, genital herpes, shingles, and chickenpox. Valtrex helps manage outbreaks, reduce the severity of symptoms, and can be used as a suppressive therapy for frequent outbreaks.

The Link Between Valtrex and Acne

The short answer to "Can Valtrex cause acne?" is yes, it can, but it is not one of the most common or severe side effects. Clinical data from post-marketing reports and indications lists acne as a side effect, and it has been reported to occur in 1% to 10% of users. This places acne in the "common" category, though it is less frequently reported than other side effects like headache, nausea, or stomach pain. The acne caused by valacyclovir is a form of drug-induced acne, which can differ from typical acne vulgaris in its appearance and underlying cause. It is often described as an "acneiform eruption," meaning it has the appearance of acne but may lack some of the typical features like comedones (blackheads and whiteheads). Instead, it often presents as monomorphic (uniform in appearance) papules and pustules.

Potential Mechanisms of Drug-Induced Acne

Unlike typical acne, which is driven by factors like hormones, bacteria, and excess sebum, drug-induced acne is a direct consequence of a medication's effect on the body. While the exact mechanism for valacyclovir is not definitively proven in the search results, the broader understanding of drug-induced acne provides some insight. Some drugs can cause acneiform eruptions by:

Altering skin flora: Some medications can disrupt the balance of microorganisms on the skin, potentially leading to folliculitis.
Causing follicular inflammation: Certain drugs can trigger inflammation within the hair follicles, leading to the formation of papules and pustules.
Immune system changes: Medications can influence the immune response, leading to skin reactions that manifest as acne-like lesions.

Allergic vs. Acneiform Reactions

It's important to distinguish between a drug-induced acneiform eruption and a true allergic reaction. An allergic reaction to valacyclovir may present with hives, itching, or a widespread rash that appears suddenly. In contrast, an acneiform eruption is a more localized rash that specifically affects the hair follicles and has the appearance of acne. If you experience swelling of the face, tongue, or throat, or have difficulty breathing, this could indicate a serious allergic reaction and requires immediate medical attention.

Differentiating Drug-Induced Acne from Other Skin Issues

When a person starts taking a new medication, especially for a condition that already affects the skin, it can be challenging to pinpoint the cause of a new rash. Here is a guide to help distinguish between drug-induced acne and other possibilities.

Is it the herpes outbreak or the medication?

For individuals taking Valtrex to treat a herpes outbreak, it is crucial to differentiate the drug's side effects from the disease itself. A herpes outbreak presents as small, painful blisters, which is distinctly different from the pustules and papules of drug-induced acne. As the herpes sores heal, they will scab over and eventually fade, a progression not seen with drug-induced acne.

What to Do If You Experience Acne While Taking Valtrex

If you believe Valtrex is causing acne, the first and most important step is to talk to your healthcare provider. Do not stop taking the medication without consulting a doctor, especially since abruptly stopping can increase the risk of the virus becoming resistant. Your doctor can help determine if the acne is related to the medication and discuss the best course of action. Treatment may involve stopping the drug if the side effect is severe, switching to an alternative, or simply managing the acne with standard treatments while continuing the antiviral therapy. Standard acne treatments, such as topical medications, may be effective for drug-induced acne.

Valtrex and Acne: A Comparison


Feature	Drug-Induced Acne (from Valtrex)	Typical Acne Vulgaris
Onset	Usually begins shortly after starting the medication.	Develops gradually, often related to puberty or hormonal changes.
Appearance	Often monomorphic (uniform) papules and pustules.	Polymorphic, with a mix of comedones, papules, pustules, and cysts.
Location	Can appear anywhere, but may be concentrated on the trunk.	Typically affects the face, chest, and back.
Cause	A direct reaction to a medication.	A multifactorial process involving hormones, bacteria (P. acnes), and genetics.
Resolution	Often resolves after stopping the offending medication.	Requires ongoing treatment and management, may recur.

Common Valtrex Side Effects (Beyond Acne)

While acne is a reported side effect, it's essential to be aware of other potential adverse effects. A list of common side effects includes:

Headache
Nausea and stomach pain
Tiredness or fatigue
Depression
Dizziness
Rash and itching (pruritus)
Photosensitivity (increased sensitivity to sunlight)

Serious side effects are rare but require immediate medical attention. These can include allergic reactions, kidney injury, confusion, and hallucinations.

Conclusion

In conclusion, can Valtrex cause acne? Yes, it is a documented side effect, affecting a small percentage of users and manifesting as a drug-induced acneiform eruption. While not a typical acne vulgaris, it can be a frustrating skin condition. Patients who notice an acne-like rash after starting valacyclovir should consult their doctor to determine the cause and appropriate management strategy, which may include stopping the medication or using topical treatments. Remember that the antiviral benefits of Valtrex for treating or suppressing herpes infections often outweigh the risk of minor side effects like acne. Always seek professional medical advice for personalized guidance regarding your treatment and side effects.

For more detailed patient information on valacyclovir, visit the MedlinePlus Drug Information.

Frequently Asked Questions

According to clinical reports, acne is considered a common side effect of Valtrex (valacyclovir), occurring in 1% to 10% of patients.

No, it is typically different. The rash is an 'acneiform eruption,' which means it looks like acne but is not caused by the same factors as typical acne vulgaris and often presents with more uniform bumps.

An allergic reaction can involve widespread hives, itching, and potentially serious symptoms like swelling or trouble breathing. An acneiform eruption is more localized to hair follicles and looks like small, uniform bumps or pustules.

You should contact your healthcare provider. They can help determine if the medication is the cause and suggest appropriate management strategies without having you stop your treatment abruptly.

There is no conclusive data suggesting that long-term suppressive therapy with Valtrex increases the risk of acne more than short-term use. If you experience this side effect, discuss it with your doctor.

Yes, other skin-related side effects can include a general rash, itching (pruritus), and increased sensitivity to sunlight (photosensitivity).

If the acne is drug-induced, it is likely to resolve after discontinuing the medication. However, you should only stop taking Valtrex under the guidance of a healthcare professional.