Herpes-like sores: Common causes and how to identify them

Overview

Sores that look like herpes but are not can be confusing and concerning, especially since herpes is one of the most well-known viral infections affecting the skin. However, several conditions can mimic the appearance of herpes, leading to misdiagnosis or unnecessary worry. It’s important to understand that while herpes typically presents with painful blisters, other skin issues like allergic reactions, canker sores, or bacterial infections can also cause similar lesions. In this article, we’ll explore what can be mistaken for herpes, helping you better identify the underlying causes and seek appropriate treatment.

What does herpes look like?

Herpes typically appears as small, painful blisters or sores on the skin. These blisters are filled with clear fluid and usually form in clusters on the mouth (oral herpes) or genitals (genital herpes). The sores may burst, leading to shallow, painful ulcers that scab over as they heal. Common symptoms accompanying herpes outbreaks include itching, burning, tingling, and redness in the affected area before the blisters form. After the initial outbreak, the virus can remain dormant and cause recurring episodes.

What can be mistaken for herpes?

Several conditions can mimic the appearance of herpes, leading to possible misdiagnosis. Below is a comprehensive list of conditions that can be mistaken for herpes:

Aphthous ulcers (Canker sores):

Aphthous ulcers are small, painful lesions that occur inside the mouth, on the gums, or inside the cheeks. They are not caused by a virus like herpes but are related to factors such as stress, minor injuries, or immune responses. Unlike herpes, canker sores do not form on the lips or skin outside the mouth and are not contagious. Aphthous ulcers tend to heal on their own within 1-2 weeks and don’t typically present with blisters, which is a hallmark of herpes.

Allergic contact dermatitis:

This condition results from an allergic reaction to substances like soaps, cosmetics, or plants (e.g., poison ivy). It leads to red, itchy, blistering rashes that may be mistaken for herpes. However, allergic contact dermatitis typically appears where the allergen made contact with the skin and lacks the viral characteristics of herpes. The sores are not painful or preceded by the itching, tingling, or burning sensation commonly experienced with a herpes outbreak.

Impetigo:

Impetigo is a bacterial infection that results in red sores or blisters, usually around the nose and mouth in children. These sores burst and develop a honey-colored crust, which is a key feature differentiating it from herpes, where sores tend to form clear, fluid-filled blisters that eventually scab over. Impetigo is caused by Staphylococcus or Streptococcus bacteria and can be treated with antibiotics, unlike herpes, which is viral and requires antiviral medications.

Eczema (Atopic dermatitis):

Eczema is a chronic inflammatory skin condition that leads to red, itchy patches, and when infected, it can form blisters that resemble herpes sores. However, eczema is usually distributed symmetrically on both sides of the body, and it lacks the clustering of blisters seen in herpes infections. Eczema is also non-contagious, whereas herpes is caused by a virus and can spread through contact.

Hand, foot, and mouth disease (HFMD): 

HFMD is a viral infection, often affecting children, caused by coxsackievirus. It produces painful blisters in the mouth and a rash on the hands and feet. While these symptoms might be mistaken for herpes, HFMD affects larger areas of the body and is typically accompanied by a fever. The distribution of sores is different, as herpes typically localizes to specific areas (lips, genitals) and is not associated with widespread rashes on the limbs.

Varicella (Chickenpox): 

Chickenpox causes itchy, blister-like rashes all over the body. While chickenpox blisters can resemble herpes lesions, the systemic nature of chickenpox, affecting large areas of the skin, helps differentiate it from herpes, which tends to be more localized. Chickenpox primarily occurs in children and is less common in vaccinated populations, whereas herpes can reoccur throughout life as cold sores or genital outbreaks.

Shingles (Herpes zoster): 

Shingles is caused by the reactivation of the varicella-zoster virus (the virus that causes chickenpox), and its blisters closely resemble those of herpes simplex. Shingles presents as painful, clustered blisters on one side of the body, typically along a single nerve path (dermatome). While both conditions involve painful blisters, shingles usually only occurs in older or immunocompromised individuals, whereas herpes simplex can affect people of all ages.

Syphilis:

Syphilis, a sexually transmitted infection caused by Treponema pallidum, produces painless ulcers (chancres) during its primary stage, which may be confused with herpes sores. However, syphilis sores tend to be larger, more ulcerative, and less painful compared to herpes blisters, which are small, painful, and fluid-filled. Additionally, syphilis chancres are typically solitary, whereas herpes usually appears as multiple blisters.

Scabies:

Scabies is caused by tiny mites that burrow into the skin, leading to intense itching and red, pimple-like rashes. Blisters may form in severe infestations, mimicking herpes lesions. However, scabies usually causes widespread itching and affects areas like the wrists, elbows, and between fingers, unlike the localized outbreaks of herpes. The presence of visible burrows under the skin also helps distinguish scabies from herpes.

Molluscum contagiosum:

This viral infection causes small, dome-shaped bumps with a central dimple. While they can appear on the genitals or face, resembling herpes in location, molluscum lesions are typically firm and painless, unlike the painful, fluid-filled blisters of herpes. Molluscum spreads through direct contact or contaminated objects, similar to herpes, but its appearance is quite distinct.

Folliculitis:

Folliculitis is an inflammation of hair follicles, often caused by bacterial or fungal infections. It results in small, pus-filled bumps, which may resemble herpes blisters. However, folliculitis is usually found around hair follicles and is often itchy rather than painful, whereas herpes blisters are painful and usually not associated with hair follicles.

Psoriasis:

Psoriasis is an autoimmune condition that causes red, scaly plaques on the skin, sometimes forming pustules that can mimic herpes sores. Genital psoriasis can resemble herpes outbreaks, but psoriasis plaques are typically thicker, scaly, and less fluid-filled compared to herpes blisters. Psoriasis is not contagious, unlike herpes, and is often associated with other autoimmune symptoms such as joint pain.

Erythema multiforme:

This hypersensitivity reaction can cause red, target-like lesions on the skin, which can sometimes be confused with herpes sores. While erythema multiforme may indeed be triggered by a herpes simplex infection, the lesions are typically larger and more generalized, affecting the limbs and trunk rather than being localized to one area as with herpes.

Lichen planus:

Lichen planus is an inflammatory condition that causes purple, flat-topped bumps on the skin or mucous membranes. While it can affect the genital region, it is typically itchy rather than painful and lacks the blistering and ulceration seen in herpes outbreaks. The lesions in lichen planus are also more chronic, while herpes sores tend to heal after a few weeks.

Pemphigus vulgaris:

Pemphigus vulgaris is an autoimmune disease that causes painful blisters and erosions on the skin and mucous membranes. The blisters in pemphigus can look similar to herpes but are more widespread and tend to be less localized. Pemphigus is also associated with more systemic symptoms, whereas herpes outbreaks are usually localized and more likely to recur in the same spots.

Chancroid:

Chancroid, caused by Haemophilus ducreyi, results in painful genital ulcers that can be mistaken for herpes lesions. However, chancroid ulcers are generally more irregular in shape and deeper than herpes sores. Chancroid also tends to be more prevalent in certain geographic regions and populations.

Behçet’s disease:

This rare inflammatory condition causes recurrent oral and genital ulcers that can resemble herpes lesions. However, Behçet’s ulcers are typically deeper and more persistent than herpes sores, and the disease also involves systemic symptoms such as joint pain, eye inflammation, and vascular problems, which are absent in herpes.

Drug reactions (SJS/TEN):

Severe drug reactions like Stevens-Johnson Syndrome (SJS) or Toxic Epidermal Necrolysis (TEN) can cause blistering skin eruptions that might be mistaken for herpes. However, drug reactions tend to be more widespread, involve the mucous membranes, and are accompanied by other symptoms like fever and malaise. In contrast, herpes usually presents as localized clusters of blisters.

Genital warts (caused by HPV):

Genital warts, caused by the human papillomavirus (HPV), appear as fleshy growths on the genital area. While warts may coexist with herpes lesions, they are usually firm, painless, and non-fluid-filled, in contrast to herpes, which produces painful, fluid-filled blisters.

Friction or trauma-related blisters:

Physical trauma or friction (e.g., from tight clothing or sexual activity) can cause blisters that resemble herpes sores. However, trauma blisters are usually larger, less painful, and are not accompanied by the systemic viral symptoms (e.g., fever, fatigue) or tingling sensation that typically precedes a herpes outbreak.

Each of these conditions has distinct causes and treatments, and a proper medical diagnosis is required to differentiate them from herpes.

Condition	Cause	Symptoms	How to Differentiate from Herpes	Picture
Aphthous Ulcers (Canker Sores)	Immune response, stress, minor injuries	Small, painful lesions inside the mouth, not contagious	No blisters occur inside the mouth, not on lips or skin outside
Allergic Contact Dermatitis	Allergic reaction to substances (e.g., soaps)	Red, itchy, blistering rash where allergen made contact	Not viral, lacks tingling or burning sensation before the outbreak
Impetigo	Bacterial infection (Staph/Strep)	Red sores around the nose and mouth, honey-colored crust	Bacterial, forms crust instead of fluid-filled blisters
Eczema	Chronic inflammatory condition	Red, itchy patches can blister in severe cases	Symmetrical patches, not contagious, lack clustered blisters
Hand, Foot, and Mouth Disease	Viral infection (Coxsackievirus)	Painful blisters in mouth, rash on hands and feet, fever	Affects larger areas, fever present, not localized to mouth or genitals
Shingles (Herpes Zoster)	Reactivation of varicella-zoster virus	Painful blisters along nerve path, usually on one side of the body	Localized to one side, affects older adults or immunocompromised individuals
Syphilis	Bacterial infection (Treponema pallidum)	Painless, larger ulcers (chancres)	Solitary ulcers, painless, no fluid-filled blisters
Scabies	Mite infestation	Intense itching, small red bumps or blisters, burrows in the skin	Generalized itching, visible burrows, not viral
Molluscum Contagiosum	Viral infection	Dome-shaped bumps with a central dimple, painless	Firm, painless, not fluid-filled like herpes blisters
Folliculitis	Inflammation of hair follicles	Small, pus-filled bumps around hair follicles, itching	Linked to hair follicles, not painful, lacks viral symptoms like tingling
Psoriasis	Autoimmune condition	Red, scaly plaques, sometimes pustules	Thick, scaly plaques, not fluid-filled, not contagious

When to consult a doctor?

You should consult a doctor under the following circumstances if you suspect you have herpes or another condition that mimics it:

• First appearance of painful blisters, sores, or ulcers; severe pain disrupting daily activities; uncertainty about whether it’s herpes or another condition.
• Frequent recurrences (more than 6 times a year); outbreaks becoming more painful or severe.
• Sores spreading beyond the genital or oral regions; symptoms lasting longer than 2-4 weeks; systemic symptoms like fever, swollen lymph nodes, or muscle aches.
• Active genital herpes outbreak while pregnant; discuss antiviral therapy during the last trimester to prevent transmission during delivery.
• Difficulty urinating due to sores; herpes sores near or in the eyes (medical emergency); signs of secondary bacterial infection (e.g., redness, swelling, pus).
• A weak immune system (e.g., HIV, cancer treatment) increases the risk of serious outbreaks.
• Emotional distress, anxiety, or relationship concerns related to herpes.

FAQs about sores that look like herpes, but are not