Herpes infections usually show no symptoms; when symptoms do appear they typically resolve within two weeks. The main symptom of oral infection is inflammation of the mucosa of the cheek and gums—known as acute herpetic gingivostomatitis—which occurs within 5–10 days of infection. Other symptoms may also develop, including headache, nausea, dizziness and painful ulcers—sometimes confused with canker sores—fever, and sore throat.

Primary HSV infection in adolescents frequently manifests as severe pharyngitis with lesions developing on the cheek and gums. Some individuals develop difficulty in swallowing (dysphagia) and swollen lymph nodes (lymphadenopathy). Primary HSV infections in adults often results in pharyngitis similar to that observed in glandular fever (infectious mononucleosis), but gingivostomatitis is less likely.

Recurrent oral infection is more common with HSV-1 infections than with HSV-2. Symptoms typically progress in a series of eight stages:

1. Latent (weeks to months incident-free): The remission period; After initial infection, the viruses move to sensory nerve ganglia (trigeminal ganglion), where they reside as lifelong, latent viruses. Asymptomatic shedding of contagious virus particles can occur during this stage.

2. Prodromal (day 0–1): Symptoms often precede a recurrence. Symptoms typically begin with tingling (itching) and reddening of the skin around the infected site. This stage can last from a few days to a few hours preceding the physical manifestation of an infection and is the best time to start treatment.

3. Inflammation (day 1): Virus begins reproducing and infecting cells at the end of the nerve. The healthy cells react to the invasion with swelling and redness displayed as symptoms of infection.

4. Pre-sore (day 2–3): This stage is defined by the appearance of tiny, hard, inflamed papules and vesicles that may itch and are painfully sensitive to touch. In time, these fluid-filled blisters form a cluster on the lip (labial) tissue, the area between the lip and skin (vermilion border), and can occur on the nose, chin, and cheeks.

5. Open lesion (day 4): This is the most painful and contagious of the stages. All the tiny vesicles break open and merge to create one big, open, weeping ulcer. Fluids are slowly discharged from blood vessels and inflamed tissue. This watery discharge is teeming with active viral particles and is highly contagious. Depending on the severity, one may develop a fever and swollen lymph glands under the jaw.

6. Crusting (day 5–8): A honey/golden crust starts to form from the syrupy exudate. This yellowish or brown crust or scab is not made of active virus but from blood serum containing useful proteins such as immunoglobulins. This appears as the healing process begins. The sore is still painful at this stage, but, more painful, however, is the constant cracking of the scab as one moves or stretches their lips, as in smiling or eating. Virus-filled fluid will still ooze out of the sore through any cracks.

7. Healing (day 9–14): New skin begins to form underneath the scab as the virus retreats into latency. A series of scabs will form over the sore (called Meier Complex), each one smaller than the last. During this phase irritation, itching, and some pain are common.

8. Post-scab (12–14 days): A reddish area may linger at the site of viral infection as the destroyed cells are regenerated. Virus shedding can still occur during this stage.

The recurrent infection is thus often called "herpes simplex labialis". Rare reinfections occur inside the mouth ("intraoral HSV stomatitis") affecting the gums, alveolar ridge, hard palate, and the back of the tongue, possibly accompanied by "herpes labialis".

A lesion caused by herpes simplex can occur in the corner of the mouth and be mistaken for angular cheilitis of another cause. Sometimes termed "angular herpes simplex". A cold sore at the corner of the mouth behaves similarly to elsewhere on the lips. Rather than utilizing antifungal creams, angular herpes simplex is treated in the same way as a cold sore, with topical antiviral drugs.

The term "labia" means "lip". Herpes labialis does not refer to the labia of the genitals, though the origin of the word is the same. When the viral infection affects both face and mouth, the broader term "orofacial herpes" is used, whereas the term "herpetic stomatitis" is used to specifically describe infection of the mouth; "stomatitis" is derived from the Greek word stoma that means "mouth".

Neonatal herpes simplex is a HSV infection in an infant. It is a rare but serious condition, usually caused by vertical transmission of HSV-1 or -2) from mother to newborn. During immunodeficiency, herpes simplex can cause unusual lesions in the skin. One of the most striking is the appearance of clean linear erosions in skin creases, with the appearance of a knife cut. Herpetic sycosis is a recurrent or initial herpes simplex infection affecting primarily the hair follicles. Eczema herpeticum is an infection with herpesvirus in patients with chronic atopic dermatitis may result in spread of herpes simples throughout the eczematous areas.

Herpetic keratoconjunctivitis, a primary infection, typically presents as swelling of the conjunctiva and eyelids (blepharoconjunctivitis), accompanied by small white itchy lesions on the surface of the cornea.

Herpetic sycosis is a recurrent or initial herpes simplex infection affecting primarily the hair follicle.

In males, the lesions occur on the glans penis, shaft of the penis or other parts of the genital region, on the inner thigh, buttocks, or anus. In females, lesions appear on or near the pubis, clitoris or other parts of the vulva, buttocks or anus.

Other common symptoms include pain, itching, and burning. Less frequent, yet still common, symptoms include discharge from the penis or vagina, fever, headache, muscle pain (myalgia), swollen and enlarged lymph nodes and malaise. Women often experience additional symptoms that include painful urination (dysuria) and cervicitis. Herpetic proctitis (inflammation of the anus and rectum) is common for individuals participating in anal intercourse.

After 2–3 weeks, existing lesions progress into ulcers and then crust and heal, although lesions on mucosal surfaces may never form crusts. In rare cases, involvement of the sacral region of the spinal cord can cause acute urinary retention and one-sided symptoms and signs of myeloradiculitis (a combination of myelitis and radiculitis): pain, sensory loss, abnormal sensations (paresthesia) and rash. Historically, this has been termed Elsberg syndrome, although this entity is not clearly defined.

HSV infection causes several distinct medical disorders. Common infection of the skin or mucosa may affect the face and mouth (orofacial herpes), genitalia (genital herpes), or hands (herpetic whitlow). More serious disorders occur when the virus infects and damages the eye (herpes keratitis), or invades the central nervous system, damaging the brain (herpes encephalitis). People with immature or suppressed immune systems, such as newborns, transplant recipients, or people with AIDS, are prone to severe complications from HSV infections. HSV infection has also been associated with cognitive deficits of bipolar disorder, and Alzheimer's disease, although this is often dependent on the genetics of the infected person.

In all cases, HSV is never removed from the body by the immune system. Following a primary infection, the virus enters the nerves at the site of primary infection, migrates to the cell body of the neuron, and becomes latent in the ganglion. As a result of primary infection, the body produces antibodies to the particular type of HSV involved, preventing a subsequent infection of that type at a different site. In HSV-1-infected individuals, seroconversion after an oral infection prevents additional HSV-1 infections such as whitlow, genital herpes, and herpes of the eye. Prior HSV-1 seroconversion seems to reduce the symptoms of a later HSV-2 infection, although HSV-2 can still be contracted.

Many people infected with HSV-2 display no physical symptoms—individuals with no symptoms are described as asymptomatic or as having subclinical herpes.

A herpetic whitlow is a lesion (whitlow) on a finger or thumb caused by the herpes simplex virus. It is a painful infection that typically affects the fingers or thumbs. Occasionally infection occurs on the toes or on the nail cuticle. Herpes whitlow can be caused by infection by HSV-1 or HSV-2. HSV-1 whitlow is often contracted by health care workers that come in contact with the virus; it is most commonly contracted by dental workers and medical workers exposed to oral secretions. It is also often observed in thumb-sucking children with primary HSV-1 oral infection (autoinoculation) prior to seroconversion, and in adults aged 20 to 30 following contact with HSV-2-infected genitals. Symptoms of herpetic whitlow include swelling, reddening and tenderness of the skin of infected finger. This may be accompanied by fever and swollen lymph nodes. Small, clear vesicles initially form individually, then merge and become cloudy. Associated pain often seems large relative to the physical symptoms. The herpes whitlow lesion usually heals in two to three weeks. It may reside in axillary sensory ganglia to cause recurrent herpetic lesions on that arm or digits.

Herpes gladiatorum is one of the most infectious of herpes-caused diseases, and is transmissible by skin-to-skin contact. The disease was first described in the 1960s in the "New England Journal of Medicine". It is caused by contagious infection with human herpes simplex virus type 1 (HSV-1), which more commonly causes oral herpes (cold sores). Another strain, HSV-2 usually causes genital herpes, although the strains are very similar and either can cause herpes in any location.

While the disease is commonly passed through normal human contact, it is strongly associated with contact sports—outbreaks in sporting clubs being relatively common.

Other names for the disease are herpes rugbiorum or "scrumpox" (after rugby football), "wrestler's herpes" or "mat pox" (after wrestling). In one of the largest outbreaks ever among high-school wrestlers at a four-week intensive training camp, HSV was identified in 60 of 175 wrestlers. Lesions were on the head in 73 percent of the wrestlers, the extremities in 42 percent, and the trunk in 28 percent. Physical symptoms sometimes recur in the skin. Previous adolescent HSV-1 seroconversion would preclude most herpes gladiatorum, but being that stress and trauma are recognized triggers, such a person would be likely to infect others.

In children the primary source of infection is the orofacial area, and it is commonly inferred that the virus (in this case commonly HSV-1) is transferred by the cutting, chewing or sucking of fingernail or thumbnail.

In adults, it is more common for the primary source to be the genital region, with a corresponding preponderance of HSV-2. It is also seen in adult health care workers such as dentists because of increased exposure to the herpes virus.

Contact sports are also a potential source of infection with herpetic whitlows.

Neonatal herpes manifests itself in three forms: skin, eyes, and mouth herpes (SEM) sometimes referred to as "localized", disseminated herpes (DIS), and central nervous system herpes(CNS).

- SEM herpes is characterized by external lesions but no internal organ involvement. Lesions are likely to appear on trauma sites such as the attachment site of fetal scalp electrodes, forceps or vacuum extractors that are used during delivery, in the margin of the eyes, the nasopharynx, and in areas associated with trauma or surgery (including circumcision).

- DIS herpes affects internal organs, particularly the liver.

- CNS herpes is an infection of the nervous system and the brain that can lead to encephalitis. Infants with CNS herpes present with seizures, tremors, lethargy, and irritability, they feed poorly, have unstable temperatures, and their fontanelle (soft spot of the skull) may bulge.

CNS herpes is associated with highest morbidity, and DIS herpes has a higher mortality rate. These categories are not mutually exclusive and there is often overlap of two or more types. SEM herpes has the best prognosis of the three, however, if left untreated it may progress to disseminated or CNS herpes with its attendant increases in mortality and morbidity.

Death from neonatal HSV disease in the U.S. is currently decreasing; The current death rate is about 25%, down from as high as 85% in untreated cases just a few decades ago. Other complications from neonatal herpes include prematurity with approximately 50% of cases having a gestation of 38 weeks or less, and a concurrent sepsis in approximately one quarter of cases that further clouds speedy diagnosis.

Herpes gladiatorum is characterized by a rash with clusters of sometimes painful fluid-filled blisters, often on the neck, chest, face, stomach, and legs. The infection is often accompanied by lymphadenopathy (enlargement of the lymph nodes), fever, sore throat, and headache. Often, the accompanying symptoms are much more of an inconvenience than the actual skin blisters and rash.

Each blister contains infectious virus particles (virions). Close contact, particularly abrasive contact as found in contact sports, causes the infected blisters to burst and pass the infection along. Autoinoculation (self-infection) can occur through self-contact, leading to infection at multiple sites on the body.

Herpes gladiatorum symptoms may last up to a few weeks, and if they occur during the first outbreak, they can be more pronounced. In recurrences of the ailment, symptoms are milder, even if lesions still tend to occur. With recurrent infections scabs may form at 3 days yet the lesions are still considered infectious up til 6.4 days after starting oral antiviral medications. Healing takes place without leaving scars. It is possible that the condition evolves asymptomatically and sores are never present.

The condition varies from a mild, self-limited rash (E. multiforme minor) to a severe, life-threatening form known as erythema multiformer major (or erythema multiforme majus) that also involves mucous membranes.

Consensus classification:

- Erythema multiforme minor—typical targets or raised, edematous papules distributed

- Erythema multiforme major—typical targets or raised, edematous papules distributed acrally with involvement of one or more mucous membranes; epidermal detachment involves less than 10% of total body surface area (TBSiA)

- SJS/TEN—widespread blisters predominant on the trunk and face, presenting with erythematous or pruritic macules and one or more mucous membrane erosions; epidermal detachment is less than 10% TBSA for Stevens-Johnson syndrome and 30% or more for toxic epidermal necrolysis.

The mild form usually presents with mildly itchy (but itching can be very severe), pink-red blotches, symmetrically arranged and starting on the extremities. It often takes on the classical "target lesion" appearance, with a pink-red ring around a pale center. Resolution within 7–10 days is the norm.

Individuals with persistent (chronic) erythema multiforme will often have a lesion form at an injury site, e.g. a minor scratch or abrasion, within a week. Irritation or even pressure from clothing will cause the erythema sore to continue to expand along its margins for weeks or months, long after the original sore at the center heals.

Genital herpes can be spread by viral shedding prior to and following the visual signs of symptoms.

Erythema multiforme (EM) is a skin condition of unknown cause; it is a type of erythema possibly mediated by deposition of immune complexes (mostly IgM-bound complexes) in the superficial microvasculature of the skin and oral mucous membrane that usually follows an infection or drug exposure. It is an uncommon disorder, with peak incidence in the second and third decades of life. The disorder has various forms or presentations, which its name reflects ("multiforme", "", from "" + ""). Target lesions are a typical manifestation. Two types, one mild to moderate and one severe, are recognized (erythema multiforme minor and erythema multiforme major).

Neonatal herpes simplex is a rare but serious condition, usually caused by vertical transmission of herpes simplex virus from mother to newborn. Around 1 in every 3,500 babies in the United States contract the infection.

Primary infection most commonly manifests as blepharoconjunctivitis i.e. infection of lids and conjunctiva that heals without scarring. Lid vesicles and conjunctivitis are seen in primary infection. Corneal involvement is rarely seen in primary infection.

This classic herpetic lesion consists of a linear branching corneal ulcer (dendritic ulcer). During eye exam the defect is examined after staining with fluorescein dye. The underlying cornea has minimal inflammation.

Patients with epithelial keratitis complain of foreign-body sensation, light sensitivity, redness and blurred vision.

Focal or diffuse reduction in corneal sensation develops following recurrent epithelial keratitis.

In immune deficient patients or with the use of corticosteroids the ulcer may become large and in these cases it is called geographic ulcer.

Herpesviral meningitis is meningitis associated with herpes simplex virus (HSV).

HSV-2 is the most common cause of Mollaret's meningitis, a type of recurrent viral meningitis. This condition was first described in 1944 by French neurologist Pierre Mollaret. Recurrences usually last a few days or a few weeks, and resolve without treatment. They may recur weekly or monthly for approximately 5 years following primary infection.

Although DNA analysis techniques such as Polymerase chain reaction can be used to look for DNA of herpesviruses in spinal fluid or blood, the results may be negative, even in cases where other definitive symptoms exist.

Symptoms:

- With resolution of the herpes zoster eruption, pain that continues for three months or more is defined as postherpetic neuralgia.

- Pain is variable, from discomfort to very severe, and may be described as burning, stabbing, or gnawing.

Signs:

- Area of previous herpes zoster may show evidence of cutaneous scarring.

- Sensation may be altered over the areas involved, in the form of either hypersensitivity or decreased sensation.

- In rare cases, the patient might also experience muscle weakness, tremor, or paralysis if the nerves involved also control muscle movement.

There are many oral and maxillofacial pathologies which are not fully understood.

- Burning mouth syndrome (BMS) is a disorder where there is a burning sensation in the mouth that has no identifiable medical or dental cause. The disorder can affect anyone but tends to occur most often in middle aged women. BMS has been hypothesized to be linked to a variety of factors such as the menopause, dry mouth (xerostomia) and allergies. BMS usually lasts for several years before disappearing for unknown reasons. Other features of this disorder include anxiety, depression and social isolation. There is no cure for this disorder and treatment includes use of hydrating agents, pain medications, vitamin supplements or the usage of antidepressants.

- Aphthous stomatitis is a condition where ulcers (canker sores) appear on the inside of the mouth, lips and on tongue. Most small canker sores disappear within 10–14 days. Canker sores are most common in young and middle aged individuals. Sometimes individuals with allergies are more prone to these sores. Besides an awkward sensation, these sores can also cause pain or tingling or a burning sensation. Unlike herpes sores, canker sores are always found inside the mouth and are usually less painful. Good oral hygiene does help but sometime one may have to use a topical corticosteroid.

- Migratory stomatitis is a condition that involves the tongue and other oral mucosa. The common migratory glossitis (geographic tongue) affects the anterior two thirds of the dorsal and lateral tongue mucosa of 1% to 2.5% of the population, with one report of up to 12.7% of the population. The tongue is often fissured, especially. in elderly individuals. In the American population, a lower prevalence was reported among Mexican Americans (compared with Caucasians and African Americans) and cigarette smokers. When other oral mucosa, beside the dorsal and lateral tongue, are involved, the term migratory stomatitis (or ectopic geographic tongue) is preferred. In this condition, lesions infrequently involve also the ventral tongue and buccal or labial mucosa. They are rarely reported on the soft palate and floor of the mouth.

Also called smoker's palatal keratosis, this condition may occur in smokers, especially pipe smokers. The palate appears dry and cracked, and white from keratosis. The minor salivary glands appear as small, red and swollen bumps. It is not a premalignant condition, and the appearance reverses if the smoking is stopped.

The term "necrotizing ulcerative gingivostomatitis" is sometimes used as a synonym of the necrotizing periodontal disease more commonly termed necrotizing ulcerative gingivitis, or a more severe form (also termed necrotizing stomatitis). The term "necrotizing gingivostomatitis" is also sometimes used.

Aphthous stomatitis is a common condition characterized by the repeated formation of benign and non-contagious mouth ulcers (aphthae) in otherwise healthy individuals. The informal term canker sores is also used, mainly in North America, although this may also refer to any mouth ulcer.

The cause is not completely understood, but involves a T cell-mediated immune response triggered by a variety of factors. Different individuals have different triggers, which may include nutritional deficiencies, local trauma, stress, hormonal influences, allergies, or genetic predisposition.

These ulcers occur periodically and heal completely between attacks. In the majority of cases, the individual ulcers last about 7–10 days, and ulceration episodes occur 3–6 times per year. Most appear on the non-keratinizing epithelial surfaces in the mouth (i.e. anywhere except the attached gingiva, the hard palate and the dorsum of the tongue), although the more severe forms, which are less common, may also involve keratinizing epithelial surfaces. Symptoms range from a minor nuisance to interfering with eating and drinking. The severe forms may be debilitating, even causing weight loss due to malnutrition.

The condition is very common, affecting about 20% of the general population to some degree. The onset is often during childhood or adolescence, and the condition usually lasts for several years before gradually disappearing. There is no cure, and treatments aim to manage pain, reduce healing time and reduce the frequency of episodes of ulceration. The term is from meaning "mouth ulcer".

Many conditions affect the human integumentary system—the organ system covering the entire surface of the body and composed of skin, hair, nails, and related muscle and glands. The major function of this system is as a barrier against the external environment. The skin weighs an average of four kilograms, covers an area of two square meters, and is made of three distinct layers: the epidermis, dermis, and subcutaneous tissue. The two main types of human skin are: glabrous skin, the hairless skin on the palms and soles (also referred to as the "palmoplantar" surfaces), and hair-bearing skin. Within the latter type, the hairs occur in structures called pilosebaceous units, each with hair follicle, sebaceous gland, and associated arrector pili muscle. In the embryo, the epidermis, hair, and glands form from the ectoderm, which is chemically influenced by the underlying mesoderm that forms the dermis and subcutaneous tissues.

The epidermis is the most superficial layer of skin, a squamous epithelium with several strata: the stratum corneum, stratum lucidum, stratum granulosum, stratum spinosum, and stratum basale. Nourishment is provided to these layers by diffusion from the dermis, since the epidermis is without direct blood supply. The epidermis contains four cell types: keratinocytes, melanocytes, Langerhans cells, and Merkel cells. Of these, keratinocytes are the major component, constituting roughly 95 percent of the epidermis. This stratified squamous epithelium is maintained by cell division within the stratum basale, in which differentiating cells slowly displace outwards through the stratum spinosum to the stratum corneum, where cells are continually shed from the surface. In normal skin, the rate of production equals the rate of loss; about two weeks are needed for a cell to migrate from the basal cell layer to the top of the granular cell layer, and an additional two weeks to cross the stratum corneum.

The dermis is the layer of skin between the epidermis and subcutaneous tissue, and comprises two sections, the papillary dermis and the reticular dermis. The superficial papillary dermis with the overlying rete ridges of the epidermis, between which the two layers interact through the basement membrane zone. Structural components of the dermis are collagen, elastic fibers, and ground substance. Within these components are the pilosebaceous units, arrector pili muscles, and the eccrine and apocrine glands. The dermis contains two vascular networks that run parallel to the skin surface—one superficial and one deep plexus—which are connected by vertical communicating vessels. The function of blood vessels within the dermis is fourfold: to supply nutrition, to regulate temperature, to modulate inflammation, and to participate in wound healing.

The subcutaneous tissue is a layer of fat between the dermis and underlying fascia. This tissue may be further divided into two components, the actual fatty layer, or panniculus adiposus, and a deeper vestigial layer of muscle, the panniculus carnosus. The main cellular component of this tissue is the adipocyte, or fat cell. The structure of this tissue is composed of septal (i.e. linear strands) and lobular compartments, which differ in microscopic appearance. Functionally, the subcutaneous fat insulates the body, absorbs trauma, and serves as a reserve energy source.

Conditions of the human integumentary system constitute a broad spectrum of diseases, also known as dermatoses, as well as many nonpathologic states (like, in certain circumstances, melanonychia and racquet nails). While only a small number of skin diseases account for most visits to the physician, thousands of skin conditions have been described. Classification of these conditions often presents many nosological challenges, since underlying etiologies and pathogenetics are often not known. Therefore, most current textbooks present a classification based on location (for example, conditions of the mucous membrane), morphology (chronic blistering conditions), etiology (skin conditions resulting from physical factors), and so on. Clinically, the diagnosis of any particular skin condition is made by gathering pertinent information regarding the presenting skin lesion(s), including the location (such as arms, head, legs), symptoms (pruritus, pain), duration (acute or chronic), arrangement (solitary, generalized, annular, linear), morphology (macules, papules, vesicles), and color (red, blue, brown, black, white, yellow). Diagnosis of many conditions often also requires a skin biopsy which yields histologic information that can be correlated with the clinical presentation and any laboratory data.

A cutaneous condition is any medical condition that affects the integumentary system—the organ system that encloses the body and includes skin, hair, nails, and related muscle and glands. The major function of this system is as a barrier against the external environment.

Conditions of the human integumentary system constitute a broad spectrum of diseases, also known as dermatoses, as well as many nonpathologic states (like, in certain circumstances, melanonychia and racquet nails). While only a small number of skin diseases account for most visits to the physician, thousands of skin conditions have been described. Classification of these conditions often presents many nosological challenges, since underlying causes and pathogenetics are often not known. Therefore, most current textbooks present a classification based on location (for example, conditions of the mucous membrane), morphology (chronic blistering conditions), cause (skin conditions resulting from physical factors), and so on.

Clinically, the diagnosis of any particular skin condition is made by gathering pertinent information regarding the presenting skin lesion(s), including the location (such as arms, head, legs), symptoms (pruritus, pain), duration (acute or chronic), arrangement (solitary, generalized, annular, linear), morphology (macules, papules, vesicles), and color (red, blue, brown, black, white, yellow). The diagnosis of many conditions often also requires a skin biopsy which yields histologic information that can be correlated with the clinical presentation and any laboratory data. The introduction of cutaneous ultrasound has allowed the detection of cutaneous tumors, inflammatory processes, nail disorders and hair diseases.