“AIDS Bumps”: How a Dermatologist Tells Them Apart From Mosquito Bites, Folliculitis and Other Itchy Rashes

The term “AIDS bumps” is something patients say among themselves, but it is not a medical diagnosis, and the misunderstandings that come with it cause far more distress than they should.

Let me begin with the two most important facts in this article.

First, no bump or rash can diagnose HIV infection by itself. In practice, most rashes that people fear are “AIDS bumps” turn out to be insect bites, folliculitis or ordinary eczema. The only thing that can answer this question is a blood test.

Second, if a test does show infection, it no longer means what people believed twenty years ago. Today’s antiretroviral medicines can suppress the virus to undetectable levels, people who take them consistently have a life expectancy close to that of the general population, and once the virus is suppressed to undetectable levels it is not transmitted sexually. The itchy bumps this article is about improve in most cases as the immune system recovers.

This article is written from a dermatologist’s point of view, that of differential diagnosis: what the bumps in front of you could be, and what to do next.

What Is Medically Called an “AIDS Bump”?

What people commonly call “AIDS bumps” usually refers to a condition doctors call pruritic papular eruption of HIV (PPE).

It is a common skin condition in people with untreated HIV, and in many cases it is the first symptom that brings a patient to the hospital, before they know they are infected.

The key point is that PPE is a reaction of the skin, not the virus acting directly on the skin. The skin of a person whose immune system is out of balance reacts to small triggers such as insect bite saliva too strongly and for too long. What clears in 2-3 days in most people can last for weeks and itch intensely in this group.

Besides PPE, the term “AIDS bumps” is also used loosely for two entirely different things: the rash of early infection and opportunistic skin diseases at very low immunity. These are separated in the sections below.

What Do “AIDS Bumps” (PPE) Look Like?

Appearance Small firm raised bumps about 2-5 millimetres across, which may be skin-coloured, red or darker than the surrounding skin. They feel quite firm, and they are not clear blisters or pus-filled pimples.

Distribution The bumps appear singly and are spread apart, not merging into patches, and they usually appear fairly symmetrically on both sides of the body.

Scratch marks This is the most telling feature. Because the itch is severe and chronic, the skin often shows scratch marks from fingernails, dried blood crusts on top of the bumps, and above all many dark marks at different stages mixed together, old and new, which shows that it has been going on for a long time.

Chronic course The bumps do not all appear at once and then clear. New ones keep appearing while older ones turn into dark marks, so bumps of different ages are seen together on the same skin.

Where Do “AIDS Bumps” Appear?

This is a very useful question for telling conditions apart, because PPE has a clear pattern of location.

• Outer arms and legs, especially the forearms and shins, are the most common sites.

• Back and shoulders, in the areas the hands can reach.

• Face and neck are affected, but less often than the arms and legs.

• Front of the trunk is affected occasionally.

Sites where it is usually not found, which helps rule it out when lesions are there, are the palms, soles, finger webs, around the navel and the genitals. If itchy bumps are clustered in the finger webs, inner wrists, waist and genitals, always think of scabies first.

Another clue is that PPE usually leaves the middle of the back, which the hands cannot reach, relatively clear, which suggests that part of the lesions come from repeated scratching rather than from the disease alone.

Are “AIDS Bumps” Itchy?

Yes, and usually unusually itchy, so much so that the itch is often what patients complain about before they mention how the bumps look.

Level of itch Severe enough to disturb sleep. Many patients say they wake in the night scratching and find blood on the sheets or crusts under their nails in the morning.

Distinctive feature Oral antihistamines, which normally work well for hives, often work only partly for PPE. This is a valuable clinical clue, because the itch does not come mainly from histamine.

Urgency Chronic itching all over the body that has not improved after 2-4 weeks of treatment is a reason to see a dermatologist, whatever the cause turns out to be.

When Do “AIDS Bumps” Appear, and at What Stage of Infection?

It is important to be clear that rashes in HIV are not of one kind, and each kind occurs at a completely different time.

Early stage after infection (2-6 weeks) A rash called acute retroviral syndrome rash appears. It is a small, flat, red rash spread across the trunk, appearing all at once, usually not itchy or only mildly itchy, and accompanied by fever, sore throat, body aches and swollen lymph nodes. It looks very much like influenza or dengue fever. This kind of rash clears on its own within 1-2 weeks.

Latent stage (many years) The skin is usually normal and there are no symptoms at all. This is the longest stage, and it is the reason the skin cannot tell you anything.

Stage when immunity begins to decline This is when PPE appears. It is usually linked to a falling CD4 count, and the lower the CD4, the more numerous the bumps and the more severe the itch.

Stage of severe immune deficiency Other opportunistic skin diseases begin to appear, which are covered in the section on skin conditions that act as warning signs.

So the answer to “When do AIDS bumps appear?” is not immediately after a risk. Chronic itchy bumps like PPE develop months to years later, not in the first week.

Why Does an Imbalanced Immune System Cause Itchy Bumps?

The most widely accepted mechanism is that the immune system tilts too far toward the type of response that deals with allergy and parasites. Eosinophil white blood cells increase and levels of the antibody IgE rise.

As a result, triggers that most people barely notice, especially insect bite saliva, set off a strong and prolonged inflammatory reaction.

Observations that support this explanation are that PPE is common in tropical regions where insects are plentiful, and that its sites match the areas not covered by clothing, which are the easiest for insects to reach.

How to Tell It Apart From Mosquito Bites and Other Insect Bites

This is the pair people confuse most, and frankly both often start with an insect bite. What differs is how the skin reacts afterwards.

Duration Mosquito bite bumps in most people go down clearly within 2-3 days. PPE bumps last for weeks to months and leave a dark mark almost every time.

Firmness A fresh mosquito bite is soft and swollen with fluid, and it flattens when pressed. A long-standing PPE bump feels hard, like a pebble under the skin.

Number and continuity Mosquito bites tend to come in episodes, a few bumps at a time. PPE has new bumps appearing constantly, with no period when the skin is clear.

Response to treatment Mosquito bites clear on their own and respond well to a mild topical steroid. PPE is often resistant to symptomatic treatment and returns as soon as treatment stops.

When to see a doctor When “mosquito bites” last more than two weeks, leave a dark mark every time, and new bumps keep appearing for months.

How to Tell It Apart From Folliculitis

Appearance Folliculitis shows as pustules or red bumps with a hair in the centre of each one. Looking closely, you can see a hair emerging from the top of the bump. PPE bumps are firm and not necessarily related to hair follicles.

Cause Common folliculitis is caused by bacteria or yeast and is related to sweat, friction and damp clothing.

Location Folliculitis favours the back, chest, upper arms and buttocks. PPE is mainly on the outer arms and legs.

An important exception One type of folliculitis, eosinophilic folliculitis, occurs only in people with low immunity. It appears as very itchy bumps on the face, neck and upper trunk above the nipple line, which is clearly different from the sites of PPE. It responds poorly to ordinary antibiotics and is a sign that further testing is needed.

When to see a doctor When folliculitis does not respond to standard treatment, or is concentrated on the face and upper trunk with severe itching.

How to Tell It Apart From Scabies

Appearance Scabies causes small red bumps together with short, wavy tracks under the skin, which are the tunnels the mite digs.

Location Very distinctive and almost the opposite of PPE: finger webs, inner wrists, armpits, around the navel, waist and genitals. In adults it usually spares the face and scalp.

The most important clue is that people in the household are itching too. Scabies spreads through close contact and shared bedding. If several people at home start itching at the same time, think of scabies first.

Urgency Scabies can be cured with a cream or tablets, but everyone in the household must be treated at the same time and bedding washed in hot water, otherwise it keeps passing back and forth.

How to Tell It Apart From Hives and Atopic Eczema

Hives The typical feature is flat, raised, swollen welts that move around. Each welt lasts no more than 24 hours and then disappears completely without leaving a mark. The clearest difference from PPE is that hives leave no dark marks and respond well to antihistamines.

Atopic eczema appears as dry, scaly patches in the skin folds: inner elbows, backs of the knees and around the neck. There is usually a history from childhood and often other allergic conditions. It forms patches, not scattered single bumps.

A caution A person who already has atopic eczema may find it flares unusually severely when the immune system changes, to the point that medicines that used to work no longer control it. That change itself should be investigated for a cause.

How to Tell It Apart From Chronic Itchy Bumps (Prurigo Nodularis)

Appearance Bumps or nodules clearly larger than PPE, about 0.5-3 centimetres, with a thickened, hard surface that is often scratched open in the centre.

Cause An itch-scratch cycle, where scratching makes the itch worse, that has gone on for months to years. It is not specific to any one disease but occurs with many chronic itch conditions, including kidney disease, liver disease, thyroid disease and immune deficiency.

Clinical significance When nodules like this are found in a young person with no underlying disease, looking for a hidden cause, including a screening blood test, is advisable.

Other Skin Conditions That May Signal an Impaired Immune System

This section is something general articles often skip, even though in practice the skin is the organ that gives the earliest warning, and a dermatologist is often the first to see it.

• Severe or unusually treatment-resistant seborrhoeic dermatitis, a red, scaly, greasy rash beside the nose, on the eyebrows and along the hairline, that has spread widely and is not controlled by standard treatment.

• Shingles in a person under 50, especially if it involves more than one nerve band or keeps coming back.

• Many molluscum contagiosum bumps in an adult, especially on the face and unusually large. This condition is uncommon in healthy adults.

• Oral thrush with no explanation, in someone who is not using an inhaled steroid or antibiotics and does not have diabetes.

• New or suddenly severe psoriasis in a person who has had it well controlled all along.

• A white patch with a ridged edge on the side of the tongue that cannot be scraped off, called oral hairy leukoplakia.

• Dark purple patches or nodules on the skin or in the mouth, which may be Kaposi sarcoma lesions and need a biopsy.

Having any of the above does not mean infection. Each has other possible causes. What it says is “this needs further evaluation”, not “a diagnosis has been made”.

How Many Days Do “AIDS Bumps” Last? Do They Go Away on Their Own?

The straight answer is that they do not go away on their own as long as the underlying cause is still there.

Each individual bump takes several weeks to flatten, and once flat it leaves a dark mark that stays for several more months. The problem is that while old bumps are subsiding, new ones appear to replace them, so overall it looks as if it never clears.

What really changes this picture is treating the underlying cause. Once antiretroviral medicines are started and immunity begins to recover, most patients see the itch decrease within 1-3 months and the bumps gradually disappear, leaving only dark marks that fade with time.

One thing to know is that in the early period after starting antiretroviral medicines, some patients have skin symptoms that get worse temporarily before improving. This happens because the recovering immune system reacts to what was left behind. It is not a sign that the medicine is not working, and the patient should consult their doctor rather than stop the medicine on their own.

Treating the Itch While Waiting for Results and for Treatment of the Cause

Treatment has two layers that must be done together.

Layer one is treating the cause. Antiretroviral medicines are what actually ends this skin problem. Everything else is only supportive.

Layer two is controlling symptoms, which is under the care of a dermatologist.

• Topical steroids The strength and duration must be set by a doctor according to the site of the lesions, because using too strong a steroid for too long causes permanent skin thinning and visible tiny blood vessels.

• Oral antihistamines They have limited effect on this type of itch, but the drowsy types may help with sleep in the short term.

• Basic skin care Bathe in room-temperature water, not hot, use a mild soap, and apply moisturiser all over while the skin is still damp. This genuinely reduces itch and can be done right away.

• Insect bite prevention This is the most overlooked part, even though it goes directly to the root of PPE. Use insect repellent, sleep under a net or in a screened room, and wear long sleeves at dusk.

• Medical phototherapy This is an option for cases that do not respond to treatment. It must be done in a medical facility under a doctor’s supervision.

• Keeping nails short It sounds minor, but it greatly reduces damage from scratching during sleep.

What not to do Do not buy strong steroid creams and apply them yourself continuously for months, do not apply antibiotic cream without an indication, and do not scrub the skin with herbs or strong disinfectants, which strip the skin’s protective barrier and make the itch worse.

Dark Marks and Scars After the Bumps Subside

This is what patients worry about most once the itch has improved.

Post-inflammatory dark marks are caused by pigment dropping into deeper layers after the skin is inflamed. They can fade on their own, but this takes several months to a year. Applying sunscreen every day helps most, because sunlight darkens the marks and makes them fade more slowly.

True scars form when scratching goes deep into the dermis and may appear as pits or raised marks. Unlike dark marks, they do not fade on their own over time and need specific treatment.

The right order is always to get the itch under control first. Treating marks while still scratching every night is wasted effort.

Can the Skin Tell Whether You Are Infected?

No, and this is the most important sentence in this article.

There are three reasons.

First, every feature described above can occur in people who are not infected. Chronic itchy insect bites, folliculitis, scabies and atopic eczema all look so alike that even doctors need a history and further tests.

Second, many people with HIV have no skin symptoms at all, especially in the latent stage that lasts for years. Normal skin therefore does not rule out infection in the slightest.

Third, comparing photos from the internet with your own skin can give the wrong answer in both directions. It makes some people panic unnecessarily and falsely reassures others so that they do not get tested.

The only thing that can answer this question is a blood test, which takes just a few minutes.

When to Get Tested, and What Is the Window Period?

The window period is the time after infection when a test does not yet show a result, because the body has not yet made enough antibodies.

• Current-generation tests that detect both antigen and antibody can usually detect infection from about 2-4 weeks after exposure.

• A repeat test at 3 months is considered a reliable confirmation in almost every case.

• Standard self-test kits can be used for screening, but a positive result must always be confirmed at a medical facility.

Testing rights in Thailand Every Thai person with an ID card is entitled to a free HIV test twice a year at public hospitals and health-insurance service units, with no referral needed and with confidential results.

If there was a risk within the last 72 hours, post-exposure prophylaxis medicine exists that must be started as soon as possible. In this case go to an emergency room immediately and do not wait to watch the skin.

When Should You See a Dermatologist?

• Chronic itchy bumps lasting more than 2-4 weeks that do not respond to over-the-counter creams.

• Itching so bad that it disturbs sleep for several nights in a row.

• New bumps keep appearing, with many dark marks accumulating across the arms and legs.

• Accompanying symptoms such as unintentional weight loss, persistent fever, night sweats or swollen lymph nodes.

• Lesions that are deep sores, have pus, are spreading quickly, or are dark purple patches that do not fade.

• Bumps or a rash that appeared after starting a new medicine, which could be a drug rash needing urgent evaluation.

Seeing a dermatologist about itchy bumps does not require you to mention any risk if you are not ready. The doctor will assess from the lesions and take a history according to standard practice, and any test is done only with the patient’s consent.

A Short Summary for Anyone Worried Right Now

• The term “AIDS bumps” is not the name of a disease. It mostly refers to pruritic papular eruption (PPE), an over-sensitive skin reaction to insect bites.

• The key features are small firm bumps, severe itch, on the outer arms and legs, chronic, and leaving many dark marks.

• Much more common look-alikes are insect bites, folliculitis, scabies, hives and atopic eczema, all of which are treatable.

• No rash can confirm or rule out infection. A blood test is the only answer, and it is free twice a year.

• If the result is positive, today’s antiretroviral medicines allow a normal life, and most skin symptoms improve as a result.

Frequently Asked Questions

When do “AIDS bumps” appear?

There are two different cases. A rash that appears early is the rash of early infection, about 2-6 weeks after exposure: small flat red patches across the trunk, all appearing at once, usually not itchy, with fever and sore throat, and clearing on its own within 1-2 weeks. The chronic itchy bumps people call “AIDS bumps” are a different thing. They usually appear months to years after infection, when immunity begins to decline, so they are not something that appears within a few days of a risk, and bumps that appear soon after a risk more often have another cause.

What do early “AIDS bumps” look like?

The rash of the early stage is actually not the hard itchy bumps many people imagine. It is a flat or slightly raised red rash a few millimetres in size, spread over the trunk, upper arms and thighs, appearing all at once within a day or two, usually not itchy or only slightly, and almost everyone has whole-body symptoms with it: fever, sore throat, aches, swollen lymph nodes, and in some people mouth sores. Overall it looks so much like an ordinary viral fever that it cannot be told apart by eye. If you have a rash like this with a fever after a risk within the past month, see a doctor for testing.

Where do “AIDS bumps” appear?

Chronic itchy PPE bumps appear mainly on the outer arms and legs, especially the forearms and shins, then the back, shoulders and face. They usually appear fairly symmetrically on both sides and usually spare the middle of the back that the hands cannot reach. Sites where they are usually not found, which helps tell conditions apart, are the palms, soles, finger webs, around the navel and the genitals. If itchy bumps are clustered in the finger webs and around the waist, especially when people at home are itching too, think of scabies first, because it is far more common and not difficult to cure.

Are “AIDS bumps” itchy?

Yes, and usually more severely than expected, to the point of disturbing sleep and causing scratching into sores without realising it during sleep. A useful clue is that oral antihistamines, which work well for hives, often work only partly for these bumps, because the itch does not come mainly from histamine. However, severe itch does not point to any single disease, since scabies, atopic eczema and the itch of kidney or liver disease can also be severe, so the location, chronic course and a physical examination must be considered together.

How many days do “AIDS bumps” take to clear?

Each bump takes several weeks to go down and leaves a dark mark for several more months, but overall it often looks as if it never clears, because new bumps keep appearing to replace the old ones. What really ends it is treating the underlying cause. Once antiretroviral medicines are started and immunity recovers, most patients’ itch improves within 1 to 3 months. In the meantime, controlling symptoms with topical medicine as prescribed by a doctor, applying moisturiser, and being serious about preventing insect bites can reduce new bumps more than most people expect.

Can I compare photos myself to see whether it is “AIDS bumps”?

Not recommended, and this method can give the wrong answer in both directions. Chronic itchy insect bites, folliculitis, scabies and atopic eczema look very similar in photos, so even doctors need a history and a physical examination. More importantly, many people with HIV have no skin symptoms at all throughout the many years of the latent stage, so normal-looking skin does not mean you are safe. If you are worried, a blood test takes just a few minutes, Thai people are entitled to a free test twice a year, and the result is confidential, which gives a far more certain answer than comparing photos.

The information in this article is for general understanding and is not a diagnosis or individual treatment. Assessment of skin lesions and any testing should be done by a doctor.

Written by Dr. Patara Voravutinon, Dermatologist · Last reviewed 6 September 2026