What Causes Blisters on a Child’s Body?

Blisters on a child’s body can come from a wide range of causes, from everyday friction and common viral infections to rarer autoimmune conditions and genetic disorders. The most frequent culprits in otherwise healthy children are viral illnesses like chickenpox and hand, foot, and mouth disease, followed by bacterial skin infections such as impetigo. But because blistering can also signal something more serious, knowing the patterns and accompanying symptoms matters for deciding when a child needs prompt medical attention.

Viral Infections Are the Most Common Cause

If your child breaks out in blisters, a virus is the most likely explanation. Several childhood viruses cause fluid-filled skin lesions, and each tends to produce a recognizable pattern.

Chickenpox (varicella) remains one of the classic blistering illnesses of childhood, even though vaccination has dramatically reduced how often it occurs. The varicella-zoster virus spreads through airborne droplets and direct contact with the fluid inside blisters.¹ The rash typically starts on the trunk, then spreads outward. Individual spots progress quickly from flat red marks to raised bumps to small blisters that crust over within a day or two. A hallmark of chickenpox is that lesions at different stages appear at the same time, so you see a mix of fresh blisters, older crusted ones, and flat red spots all together. In most children the illness resolves on its own, though the itching can be intense. Widespread vaccination since the 1970s has cut pediatric chickenpox cases substantially, though breakthrough infections in vaccinated children still occur and tend to be milder.²

Hand, foot, and mouth disease (HFMD) is extremely common in children under five. The illness produces small blisters on the hands, feet, and inside the mouth, and sometimes on the buttocks, knees, and around the lips.³ It tends to pop up in small outbreaks during summer and autumn. The viruses most responsible are coxsackievirus A16 and enterovirus A71, though more recent surveillance shows coxsackievirus A6 and A10 are becoming increasingly common causes.⁴ Most cases clear up within a week without treatment, but the mouth sores can make eating and drinking painful enough to cause dehydration. Rare complications include brain inflammation and other neurological problems, particularly with enterovirus A71.⁵

Eczema herpeticum is less common but worth knowing about, especially if your child has eczema or another condition that disrupts the skin barrier. This happens when the herpes simplex virus (the same virus family behind cold sores) spreads across skin already damaged by eczema. The blisters look distinctive: small, dome-shaped, uniform in size, and clustered together. They tend to rupture and leave tiny punched-out ulcers, often on the face, neck, and upper trunk. Children may also develop fever and swollen lymph nodes.⁶ Eczema herpeticum is considered a medical emergency because the infection can spread to the eyes or, rarely, to internal organs. Early treatment with antiviral medication like acyclovir is critical.⁷

Bacterial Skin Infections

Bacteria, particularly Staphylococcus aureus, can cause blistering that looks alarming but is usually treatable with antibiotics once recognized.

Bullous impetigo is the blistering form of impetigo, a common skin infection in young children. Instead of the honey-colored crusts associated with typical impetigo, bullous impetigo produces fragile, fluid-filled blisters that pop easily and leave behind raw, moist patches. The blisters form because specific strains of S. aureus release exfoliative toxins that act like molecular scissors, severing a key adhesion protein called desmoglein 1 that holds superficial skin cells together.⁸ The result is a clean split in the outermost layer of skin, which fills with fluid.

At the severe end of the same spectrum sits staphylococcal scalded skin syndrome (SSSS), where those same toxins enter the bloodstream and cause widespread peeling across large areas of the body. In SSSS, the child’s skin becomes red, tender, and sheets of it may slough off with gentle pressure. It looks frightening and requires hospital care, but the toxins target only the very surface layer of skin, so healing without scarring is typical once the infection is treated.⁹

Friction, Burns, and Other Physical Causes

Not every blister involves an infection. Physical forces acting on the skin are a straightforward and common cause of blistering in active children.

Friction blisters happen when repeated rubbing separates layers within the skin’s outer tissue. The gap fills with fluid that resembles plasma but has a lower protein concentration.¹⁰ Ill-fitting shoes are the classic trigger in children, but blisters can also form on hands from gripping playground equipment, sports gear, or tools. Heat, moisture, and soft skin all make friction blisters more likely, which is why children who are active in warm weather are especially prone. These blisters are harmless on their own, though a popped blister can become a doorway for infection if not kept clean.

Burns, whether from hot liquids, contact with a hot surface, or sunburn, produce blisters when the injury goes deep enough to damage the layer just below the skin surface. Sunburn blisters deserve special mention in children because their skin is thinner and more susceptible to ultraviolet damage than adult skin. A severe sunburn with blistering is a second-degree burn and should be treated accordingly: cool compresses, pain relief, and medical evaluation if the area is large.

When Plants and Sunlight Combine

One blistering pattern that catches parents off guard is phytophotodermatitis, sometimes called “lime disease” (not to be confused with Lyme disease from tick bites). It happens when a child’s skin contacts the juice of certain plants and is then exposed to sunlight. Common culprits include limes, lemons, celery, wild parsnip, and figs.¹¹ The plant juice contains compounds called furocoumarins, which are activated by ultraviolet light and cause a burn-like skin reaction. The result is streaky redness and blistering that follows the pattern of wherever the juice dripped or was smeared.

This pattern often puzzles parents and sometimes raises concerns about possible abuse, because the marks can look like deliberate burns. It was documented as common enough in Southern California to be called endemic “lime” disease in a pediatric case series.¹² The key clue is the distribution: the blisters and dark marks follow drip lines or handprint-shaped patches, and the child typically has a history of outdoor play involving citrus fruit or garden plants. The blisters heal on their own, though the brownish discoloration left behind can persist for weeks or months.

Drug Reactions That Cause Blistering

Certain medications can trigger blistering reactions in children, and though these are rare, they can be life-threatening. The most serious are Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN), which sit on a spectrum of the same condition differentiated by how much skin is involved. When less than about a tenth of the body surface peels, it is classified as SJS; when more than about a third is affected, it is TEN.¹³

SJS and TEN typically begin with fever, malaise, and painful mouth sores before the skin starts to blister and slough. The mucous membranes of the eyes, mouth, and genitals are often involved. In children, antibiotics (particularly sulfonamides), anti-seizure medications, and nonsteroidal anti-inflammatory drugs are the most commonly implicated medications, though infections alone can also trigger the reaction.¹⁴ Because these conditions carry serious risks of scarring, eye damage, and organ complications, any child developing widespread blisters alongside mucous membrane involvement and recent medication use should be evaluated urgently.¹⁵

Researchers have suggested grouping the medication-triggered forms under a single term, drug-induced epidermal necrolysis, to emphasize that SJS and TEN are a continuum rather than separate diseases.¹⁶ The practical implication for parents is that the early signs (fever, sore mouth, eye redness, skin tenderness) should never be ignored in a child who recently started a new medication.

Erythema Multiforme and Look-Alikes

Erythema multiforme (EM) is an inflammatory skin reaction that produces distinctive “target” lesions: concentric rings of color that resemble a bullseye. In some cases the center of the target blisters. EM in children is commonly triggered by infections rather than drugs, and one of the most notable triggers is Mycoplasma pneumoniae, a bacterium that causes a type of walking pneumonia. One study found that about six in ten children with the more severe, mucosal-involving form of EM tested positive for M. pneumoniae, and these children were older at presentation and more likely to have atypical targets with central blistering.¹⁷

EM is often confused with SJS, but the two are distinct conditions with different causes and outcomes. EM lesions are fixed (they do not come and go like hives), tend to appear on the extremities, and usually resolve without lasting damage. SJS, by contrast, involves much more extensive mucous membrane involvement and widespread blistering with skin detachment.¹⁸ If your child has target-shaped spots that are not spreading rapidly and the mucous membranes look relatively uninvolved, EM is the more likely diagnosis, but a pediatrician should make that call.

Autoimmune Blistering Diseases in Children

Autoimmune blistering conditions are uncommon in children, but one in particular stands out: linear IgA bullous dermatosis (LABD), also called chronic bullous disease of childhood (CBDC). In this condition, the child’s immune system produces IgA antibodies that attack proteins anchoring the outer skin to the layers beneath, causing large, tense blisters. A distinctive clinical sign is the “cluster of jewels” pattern, where new blisters form in a ring around a healing central blister.¹⁹

The antibodies target fragments of a structural protein called BP180 at the junction between the skin’s outer and deeper layers.²⁰ The condition can involve mucous membranes, and when it does, complications are more likely to be severe. In one single-center study, all five children with mucous membrane involvement required hospitalization.¹⁹ The disease typically lasts several years and then remits on its own, but children may need dapsone or other immune-suppressing medications to control flares in the meantime.

Genetic Conditions That Cause Blistering From Birth

Some children are born with skin that blisters at the slightest touch due to inherited mutations affecting the structural proteins that hold skin layers together.

Epidermolysis bullosa (EB) is a group of rare inherited disorders where the skin is extremely fragile. There are four main subtypes, and all can present with widespread blisters at birth, making them difficult to distinguish from one another on appearance alone.²¹ The underlying problem is mutations that impair either the adhesion within the outermost skin layer or the anchoring of that layer to the tissue beneath it.²² Everyday handling, diaper changes, and clothing friction can all trigger blistering. Milder forms may produce blisters mainly on the hands and feet, while severe forms affect large areas of the body and the mucous membranes. There is no cure for EB at present, though gene therapy research is active. Management centers on preventing skin trauma, meticulous wound care, and monitoring for complications such as infection and scarring.

Incontinentia pigmenti (IP) is another genetic condition that can present with blistering in newborns. It is X-linked, meaning it predominantly affects girls (boys with the mutation rarely survive to birth). In a study of 40 patients, blisters and redness appeared as early as the first day of life in roughly seven out of ten cases, and skin lesions were present before two weeks of age in nine out of ten.²³ The blisters in IP tend to follow a linear pattern along the limbs, which is different from the scattered distribution of most infectious blisters. IP progresses through distinct phases: blistering gives way to warty raised lesions, then streaky brown pigmentation, and finally pale, hairless patches. Beyond the skin, IP can affect the teeth, eyes, and central nervous system, so a thorough evaluation is needed if the diagnosis is suspected.²⁴ The blistering phase of IP can mimic a herpes infection in newborns, which sometimes leads to unnecessary antiviral treatment before the correct diagnosis is made.²⁵

Scabies and Bullous Scabies

Scabies is a skin infestation caused by a tiny mite that burrows into the outer layer of the skin, causing intense itching and a bumpy rash. In most cases the rash consists of small red papules and fine burrow tracks, especially between fingers, on wrists, and in skin folds. But there is a less common variant called bullous scabies, where tense blisters form that can resemble autoimmune blistering diseases. The exact reason some people develop blisters rather than the typical rash is not fully understood, but it may involve a secondary staph infection or the body producing autoantibodies in response to enzymes released by the mites.²⁶ Bullous scabies is more frequently reported in older adults, but it can occur in children. The danger here is misdiagnosis: if the blisters are treated as an autoimmune condition while the underlying mite infestation is missed, the rash will persist or worsen.

When a Child Creates Their Own Blisters

This is an uncomfortable topic, but it is one that dermatologists and pediatricians encounter: self-inflicted skin injury, sometimes called dermatitis artefacta. In a retrospective review of 44 pediatric patients with self-inflicted skin lesions, blisters accounted for about 16% of cases, making them the third most common form after excoriations and ulcers.²⁷ Children may produce blisters by rubbing, applying chemical irritants, or using heat. The lesions tend to appear in locations the child can easily reach, and their shapes often look oddly geometric or do not match any recognizable disease pattern.

Self-inflicted blistering is more often a sign of underlying psychological distress than deliberate deception. The child may not fully understand or be able to articulate what they are doing or why. Approaching the situation with curiosity rather than accusation is important, as is involving a mental health professional alongside dermatological care.

Practical Clues for Parents

With so many possible causes, a few practical observations can help you and your child’s doctor narrow things down quickly:

• Distribution: Blisters limited to hands, feet, and mouth point toward HFMD. A trunk-first pattern suggests chickenpox. Linear streaks on areas exposed to plants and sun suggest phytophotodermatitis. A ring of blisters around a healing center (“cluster of jewels”) is suggestive of LABD.
• Age at onset: Blisters present from birth or the first days of life raise the possibility of genetic conditions like EB or IP. Blistering illnesses that appear in toddlers and preschoolers are most often viral.
• Mucous membrane involvement: Sores inside the mouth, on the eyes, or in the genital area alongside skin blisters raise the urgency. HFMD causes mouth sores but the child is otherwise well. SJS/TEN involves extensive mucosal damage and the child appears systemically unwell.
• Recent medications: A new drug started within the past few weeks before widespread blistering should be flagged immediately as a possible trigger for SJS/TEN.
• Itching pattern: Severe itching that worsens at night, especially between fingers or in skin folds, is a hallmark of scabies and should prompt a careful look for burrow tracks.

No list replaces a medical evaluation, and blistering over large areas of a child’s body, blisters accompanied by high fever, or any involvement of the eyes always warrants urgent medical attention. But having a sense of the landscape can help you describe what you are seeing more effectively to the doctor and understand the questions they ask in return.

How Vaccination Has Changed the Picture

The landscape of childhood blistering illnesses has shifted meaningfully over the past few decades, largely because of vaccines. The varicella vaccine, developed in Japan in the 1970s and adopted widely in other countries from the 1990s onward, has substantially reduced the incidence of chickenpox in children.² Global burden data show that the age-standardized incidence rate of varicella-herpes zoster has fallen sharply in people under 20, while it has climbed in adults over 50.²⁸ The practical result for parents is that chickenpox, once an almost-universal childhood experience, is now something many pediatricians rarely see in their fully vaccinated patients. When they do see blisters, the differential has shifted toward other causes: HFMD, impetigo, allergic reactions, and the rarer autoimmune or genetic conditions now make up a proportionally larger share of what walks into the clinic.