What does herpes look like?

You've noticed a sore patch or a few small blisters, and you're scrolling through photos trying to decide whether it's herpes. It's hard to judge on a phone screen, and it's one of the most common reasons people come to see us.

Herpes looks different at each stage. First there's a patch of tingling or itchy skin, then a cluster of small blisters, then shallow ulcers, then a crust as it heals. It can appear on the genitals, anus, mouth or lips, because both HSV-1 and HSV-2 can infect any of these sites.

If you have a sore now, the clearest next step is a herpes test while it's still visible. A PCR swab of the sore is £120.63, with results within 3 working days. You can walk in seven days a week at 117a Harley Street.

What are the first signs of herpes?

The first sign is often tingling, itching or a burning feeling on the skin, sometimes a day or two before anything is visible. That's the virus travelling along the nerve to the skin surface. Some people also feel generally unwell, with aching or swollen glands in the groin, before any mark appears. This early stage is easy to dismiss as irritation. It's usually the next stage, when small blisters form, that makes people look more closely.

What do the blisters and sores actually look like?

The blisters are small, filled with fluid and usually appear in a cluster rather than as a single spot. They sit on a reddened base of skin, on the shaft or head of the penis, the vulva, the anus, the mouth or the lips. Within a day or two they break open and leave shallow, often painful ulcers. These can weep or sting, particularly when urine passes over them. Then they dry out and form a crust while the skin heals underneath. In a first episode, the whole cycle from first blister to healed skin can take up to 3 to 4 weeks.

Does a first outbreak look different from a repeat one?

Yes. A first episode is usually more extensive and more uncomfortable than any outbreak that follows. Along with the sores, it can bring flu-like symptoms: fever, headache, muscle aches and tender, swollen lymph nodes in the groin. Recurrences tend to involve fewer blisters in roughly the same area, and they heal faster with milder discomfort. Many people feel the same tingling before each recurrence. If a doctor has prescribed treatment in advance, that warning sign is the moment to start it.

Does herpes look the same on the penis, vulva, anus and mouth?

The pattern of tingling, blistering, ulceration and crusting is the same wherever it occurs. What changes is the skin it appears on. On the penis, blisters and ulcers typically appear on the shaft, glans or foreskin. On the vulva they can affect the labia and the area around the vaginal opening. Swelling there can make the whole area feel sore rather than showing one clear lesion. Around the anus, sores can be mistaken for a fissure or piles. On the mouth and lips, herpes usually shows as a cold sore: a cluster of small blisters at the edge of the lip that crusts over within a few days.

What else can look like herpes?

Several other conditions cause marks or sores in the same area. That's why an examination and the right test tell you more than matching a description online.

A short summary of what tends to be confused with herpes, and how it's told apart.

Genital warts and molluscum tend to be painless bumps rather than blisters or ulcers. Folliculitis and ingrown hairs sit around hair follicles instead of forming a cluster of blisters. Thrush more often causes redness, itching and a white discharge than a defined sore. These can overlap, especially in early or mild cases, so an examination is more reliable than comparing photographs. A doctor who has seen many of them can usually tell them apart on sight, then confirm with the right test. Our herpes myths and facts page covers more of the common misconceptions. Whether you have an active blister to swab today (£120.63) or want to check for HSV-1 and HSV-2 antibodies on a blood sample (£103.75), our private herpes test in London returns results within 3 working days.

How is herpes tested and confirmed?

The most accurate way to confirm herpes is a swab taken directly from an open sore or blister while it's still there, because this tests for the virus itself. A blood test looks for antibodies your immune system has made after an infection. It can show that you've been exposed to HSV-1 or HSV-2 at some point. What it can't tell you is where the infection is, when you caught it, or whether the sore in front of you is herpes. If there's no sore to swab and you'd like a blood test after a possible exposure, it's generally more reliable from around 12 weeks afterwards. By then, antibodies have had time to develop.

Getting tested at our Harley Street clinic

Come in as soon as you can after a sore appears, ideally while it's still fluid-filled and before it crusts over. That's when the sample holds the most virus. The PCR swab is £120.63. The blood antibody test is £103.75 and needs no preparation. Both come back within 3 working days, and both are available as a walk-in appointment seven days a week at 117a Harley Street. Every visit is confidential, and you can read how private STI testing in London works before you come.

If you'd like to check for more than this one symptom, the Silver package includes HSV I and II alongside chlamydia, gonorrhoea, HIV, syphilis, Mycoplasma genitalium, Ureaplasma and Gardnerella.

Book a herpes test at 117a Harley Street, seven days a week.

References

• Genital herpes, NHS
• Genital herpes, NICE Clinical Knowledge Summaries
• UK national guideline for the management of genital herpes, British Association for Sexual Health and HIV (BASHH)
• Syphilis, NHS
• Genital warts, NHS