Alphabetical List of Common Rashes and Their Causes

All rashes are different. They have different presentations, causes, and treatments.

Clinicians diagnose rashes based on pattern recognition. If the type of rash is obvious, or the clinician is experienced, pattern recognition works well when diagnosing a rash.

Before we look at an alphabetical list of different types of rashes, we need to define some common terms used to describe these lesions. We’ll use some of these terms in the alphabetical list of rashes, so you may want to refer back to the list as you peruse this article.

Basic Definitions

The term dermatitis is used to describe a simple rash. Here are some other common terms used to describe rashes:

• Bulla (plural bullae): A fluid-filled sac that is greater than 1 cm in diameter.
• Comedone: A plug made of skin oils and keratinous material found in a follicle. An open comedone is black (“blackhead”) and a closed comedone is white (“whitehead”).
  
• Lichenification: Thick or leathery appearance to the skin.
  
• Macule: A flat lesion that is less than 1 cm in diameter.
• Nodule: Solid, elevated lesion between 1 cm and 5 cm in diameter.
• Papule: A solid “bump” that is less than 1 cm in diameter.
• Papulosquamous: A lesion consisting of papules and plaques with superficial scaling.
  
• Patch: A flat lesion that is greater than 1 cm in diameter.
• Petechia: A pinpoint purple or red spot caused by bleeding under the skin.
• Plaque: A raised lesion that resembles a plateau and is greater than 1 cm in diameter. Often, a plaque is made up of a convergence of smaller papules.
  
• Purpura: Purple spots on the skin caused by bleeding under the skin.
  
• Pustule: An elevated blister of any size filled with pus.
  
• Vesicle: A fluid-filled sac that is less than 1 cm in diameter.
• Wheal: An inflamed plaque or papule accompanied by swelling and itchiness.

Acne Vulgaris

Clinical presentation: Pustules, papules, comedones, nodules on face, chest, and back

Principal age group(s): Adolescents

Cause: Associated with hormone changes of puberty. Severe acne runs in families. Finding a link to food is an active area of interest.

Course: Acne typically goes away during adulthood, but resultant scarring and pitting from acute acne can be lifelong.

Acne vulgaris, or “acne,” is so common that mild cases have been termed “physiologic,” and mild acne is not a disease or illness per se.

Here are the steps in acne formation:

1. Overgrowth of follicles (comedones)
2. Excess sebum production
3. Inflammation
4. Infection with the bacteria Propionibacterium acnes

Acne often requires treatment by a physician to minimize discomfort and reduce the risk of long-term scarring. Acne should be treated early and is often treated using various medications. Cleansing is also important. Common treatment options include retinoid combinations applied to the skin, antibiotics, and benzoyl peroxide. Proactive, which is a popular over-the-counter treatment, contains benzoyl peroxide and salicylic acid and is advertised to cleanse, tone, hydrate, and protect the skin from the sun.

Atopic Dermatitis (Atopic Eczema)

Clinical presentation: Itchy papules, lichenification, rash on face and arms

Principal age group(s): Infants, young children

Cause: Associated with allergies

Course: Chronic and relapsing, some children outgrow it

Atopic dermatitis is an itchy skin condition that runs in families. Mild cases of atopic dermatitis can be treated with topical steroids (glucocorticoids), available over-the-counter. More severe cases may be treated with tacrolimus and pimecrolimus, which are immunomodulators prescribed by a physician. People who have atopic dermatitis should avoid allergens that trigger the conditions, such as detergents and animal dander.

Bullous Pemphigoid

Clinical presentation: Bullae

Principal age group(s): Elderly people

Cause: Autoimmune

Course: Waxes or wanes, remission in many

Bullous pemphigoid is a rare, inflammatory autoimmune disease that results in blistering of the skin and mucous membranes in older adults. Treatment of bullous pemphigoid is complex and requires input from various specialists, including dermatologists, ophthalmologists, and primary care physicians. More severe cases may require treatment with systemic corticosteroids.

Dermatitis Herpetiformis

Clinical presentation: Papules and vesicles on the extensor surfaces of the arms and legs

Principal age group(s): People between 30 and 40 years old

Course: Long term but can go into remission; remission is defined as lasting two-plus years

Dermatitis herpetiformis is an itchy rash that appears in a symmetrical pattern over the extensor surfaces of the body. The bumps and blisters of this condition resemble infection with the herpes virus. It is more common in men and usually affects people of Northern European descent. Symptoms of dermatitis herpetiformis usually clear after the consumption of a gluten-free diet.

Erythema Multiforme

Clinical presentation: Target lesions

Principal age group(s): Young adults

Cause: Allergic reaction

Course: Transient, one to two weeks

Erythema multiforme is a short-lasting inflammatory skin condition. The rash appears as red welts and affects the eyes, mouth, and other mucosal surfaces. The rash of erythema multiforme takes the form of concentric circles or target lesions.

This condition is a type of allergic reaction and can appear secondary to herpes infection, fungal infections, streptococcal infection, or tuberculosis. Erythema multiforme can also result from chemicals or medications, such as NSAIDs, allopurinol, and certain antibiotics. Finally, erythema multiforme can accompany inflammatory bowel disease and lupus.

There are two types of erythema multiforme. Erythema multiforme minor results in mild illness that affects only the skin and sometimes causes mouth sores. Erythema multiforme major starts with systemic symptoms that affect the entire body, such as achiness in the joints and fevers. Sores may be more serious and affect the genitals, airways, gut, or eyes.

These other symptoms can also accompany the rash in erythema multiforme major:

• Fever
• Malaise
• Achiness
• Itchy skin
• Achy joints

Typically, erythema multiforme goes away on its own without treatment. Certain treatments can be administered including steroids, antihistamines, antibiotics, moist compresses, and pain medicines. It’s important to keep lesions clean and maintain good personal hygiene to limit the risk of secondary infection.

Erythema Nodosum

Clinical presentation: Poorly circumscribed, painful, reddened plaques usually found at the level of the shins, calves, arms, and thighs; over weeks, the plaques flatten out and take on the appearance of bruises

Principal age group(s): All ages

Cause: In about half the cases, the cause is unknown. Other causes include infections and medications, such as antibiotics. Erythema nodosum can also occur during pregnancy, leukemia, sarcoidosis, and rheumatic fever.

Course: Uncomfortable, typically resolves after six weeks

Erythema nodosum is a form of panniculitis, or inflammation of the layer of fat underneath the skin. The skin lesions first begin as flat, firm, inflamed lumps, about one inch in diameter. These painful lumps may become purplish after a few days. After several weeks, the lesions become brownish, flat patches.

In addition to skin lesions, erythema nodosum can also cause more general symptoms, including fever, general malaise, achiness, and swelling. Treatment depends on the underlying cause and can include either treatment of the underlying infection or disease or discontinuation of a drug. Other treatments include steroids, NSAIDs, warm or cold compresses, or pain medicines.

Folliculitis

Clinical presentation: Infected pustules mostly affecting the face, buttocks, extremities, and trunk

Principal age group(s): All ages

Cause: Bacterial, viral, or fungal

Course: Typically resolves

Folliculitis is an inflammation of the hair follicle. It can be either on the surface and affect only the upper hair follicle, or it can run deep and inflammation can affect the entire depth of the follicle. Deeper infection can lead to boils. Folliculitis can be of bacterial, viral, or fungal origin.

Additionally, folliculitis can be caused by noninfectious agents such as tight-fitting clothing, topical steroids, ointments, makeup, and lotions. Treatment is determined by the cause of the folliculitis and includes antiviral, antibiotic, or antifungal medications.

Herpes

Clinical presentation: “Cold sores,” vesicles, and ulcers; in children, inflammation of the lining of the mouth and gums (i.e., gingivostomatitis)

Principal age group(s): All ages

Cause: Viral

Course: Typically resolves

The World Health Organization (WHO) estimates that 3.7 billion people younger than 50 years old are infected with the herpes simplex virus (HSV-1). The HSV-1 virus is spread through oral contact. Although cold sores can be unsightly and uncomfortable, they cause no other symptoms. Antiviral ointments or creams can relieve the burning, itching, and discomfort associated with cold sores.

On a related note, infection with herpes simplex virus type 2 (HSV-2) causes genital herpes. Genital herpes is sexually transmitted. However, HSV-2 can also cause cold sores. The WHO estimates that 13 percent of the world’s population are infected with genital herpes.

Herpes Zoster (Shingles)

Clinical presentation: Redness, vesicles

Principal age group(s): Elderly people

Cause: Varicella zoster virus reactivation

Course: Two to three weeks

Herpes zoster, or shingles, is a painful skin rash that is caused by the varicella zoster virus. This virus also causes chickenpox—more specifically, initial infection with varicella zoster virus causes chickenpox in childhood. After the chickenpox clears up, the virus stays dormant in nerve cells for many years. Reactivation of the virus leads to shingles.

With herpes zoster, pain precedes the rash. The rash is distributed along dermatomes on the back, face, eyes, neck, or mouth. Other symptoms of herpes zoster include weakness, fever, joint pain, and swollen glands.

There is no cure for herpes zoster. Treatments include pain medications, steroids, antiviral drugs, and antihistamines. There is a vaccine for herpes zoster, which is different from the chickenpox vaccine. Called the shingles vaccine, it reduces the risk of complications of the illness.

Impetigo

Clinical presentation: Pustules, vesicles, honey-colored crusting, reddened areas of skin erosion

Principal age group(s): Children between 2 and 6 years old

Cause: Bacterial

Course: Resolution after a few days

Impetigo is the most superficial type of skin infection. Impetigo is caused by S. aureus or Streptococcus bacteria. Impetigo is contagious and is spread among members of the same household. Impetigo is common in areas where people have little access to soap and clean water, such as in developing nations. Impetigo is also common among homeless people.

Both topical and oral antibiotics can be used to treat impetigo. If the impetigo is caused by MRSA, a drug-resistant bacteria, then oral antibiotics are needed. The best way to prevent MRSA is to practice good personal hygiene and avoid sharing clothes and towels.

Lichen Simplex Chronicus

Clinical presentation: Plaques, lichenification

Principal age group(s): People between 30 and 50 years old

Cause: Unknown

Course: Long term, remits with treatment

Lichen simplex chronicus is a chronic skin condition caused by itching and scratching. Depression, anxiety, obsessive compulsive disorder, and sleep disturbances can all play a crucial role in the cause and continued course of lichen simplex chronicus. People with allergies and atopy are predisposed to developing lichen simplex chronicus.

Continuous itching can eventually lead to thickened areas of skin. Antihistamines and steroids can be used to reduce the itch of lichen simplex chronicus. Once the itch is controlled, lichen simplex chronicus can remit.

Pityriasis Rosea

Clinical presentation: Herald patch, papules, and scales (i.e., papulosquamous)

Principal age group(s): Any age, but most commonly seen in people between 10 and 35 years old

Cause: Unknown

Course: Rash can persist between three and five months

The herald patch is the hallmark of pityriasis rosea and appears on the trunk. The herald patch is a solitary, oval, flesh- or salmon-colored lesion with scaling at the border. It’s between 0.8 and four inches in diameter. One or two weeks after the appearance of the herald patch on the trunk, numerous smaller papulosquamous lesions fan out along ribs in a Christmas-tree pattern.

Except for skin manifestations, there are no other symptoms of pityriasis rosea. In about a quarter of people, this condition is itchy. Pityriasis rosea resolves on its own and doesn’t require treatment. However, topical steroids and antihistamines may help reduce itching.

Psoriasis

Clinical presentation: Papules or plaques with silvery scales (i.e., papulosquamous)

Principal age group(s): Mostly adults, but can occur at any age

Cause: Autoimmune

Course: Long term

Psoriasis is a chronic, autoimmune, inflammatory skin disease that causes raised, red lesions with silvery scales. Plaque psoriasis is the most common type of psoriasis, accounting for about 90% of all cases of the disease. The plaques tend to enlarge slowly over time and present symmetrically on the elbows, knees, scalp, buttocks, and so forth.

Psoriasis can also affect the joints, resulting in psoriatic arthritis. New research points to the fact that psoriasis is a generalized inflammatory disorder that could raise cardiovascular risk, including stroke, heart attack, and death.

Mild psoriasis can be treated with hydrocortisone or other topical creams. Moderate to severe psoriasis can be treated with immunomodulators.

Rocky Mountain Spotted Fever

Clinical Presentation: Petechiae on the palms or soles

Principal age group(s): Any age

Cause: Tick-borne bacteria called Rickettsia rickettsii

Course: One to two weeks

Rocky Mountain spotted fever classically presents with rash, headache, and fever that occurs after a recent tick bite.

With Rocky Mountain spotted fever, older children and adults first develop a headache, followed by pains and aches in the muscles and joints.

Although Rocky Mountain spotted fever is found throughout the United States, it is most common in the southern Atlantic and south central states. It is also found in Oklahoma. Typically, people are infected with Rocky Mountain spotted fever during warm months of the year when ticks are active.

Several steps can be taken to prevent tick bites, including the following:

• Wearing long-sleeved clothing
• Using clothing and gear that is treated with permethrin
• Performing tick checks on yourself and pets
• Showering as soon as you return home from a wooded area

The rash is first maculopapular (combining the features of macules and papules) and occurs on the wrists and ankles. The rash then spreads to the body where it manifests as petechiae. Thrombocytopenia, or low platelet count, is common with Rocky Mountain spotted fever and causes petechiae.

The antibiotic doxycycline is used to treat this infection. Treatment with doxycycline is most effective when started within the first three to five days of the illness. Patients with neurological symptoms, vomiting, unstable vital signs, or compromised kidney function should be hospitalized.

Rosacea

Clinical presentation: Redness of the central face and pustules

Principal age group(s): Middle-aged and elderly adults

Cause: Unknown

Course: Long term, flare-ups and remissions

Rosacea is a chronic disease that results in redness and bumps of the face and acne. It is an inflammatory condition that affects the face and the eyes; it typically progresses over time. Rosacea can cause facial discomfort.

Rosacea generally leads to the following:

• Swollen nose
• Thick facial skin
• Flushing
• Red lines on the face
• Visible blood vessels on the face
• Red, itchy eyes

Rosacea is most common among white women. Depending on type and severity, rosacea can be treated with antibiotics, lasers, or surgery.

Seborrhea

Clinical presentation: Poorly demarcated, red plaques with greasy, yellow scales usually around the scalp, eyebrows, forehead, cheeks, and nose; can also affect the body

Principal age group(s): Men between 20 and 50 years old

Cause: Unknown

Course: Long term, relapsing

Seborrhea is a chronic, inflammatory condition that affects the parts of the face that produce sebum. Sebum is an oily secretion produced by sebaceous glands. Infants can have seborrhea of the scalp (cradle cap) or seborrhea that affects the diaper area. People with seborrhea may be more likely colonized with Malassezia, a type of yeast. Although people with HIV/AIDS often have seborrhea, the vast majority of people with seborrhea have normal immune systems. Seborrhea is mainly treated with topical antifungal medications.

Tinea

Clinical presentation: Red, ring-shaped skin patches, with scaly border; the central clearing may not be red

Principal age group(s): All ages

Cause: Fungus

Course: Usually resolves after over-the-counter antifungal treatment

Tinea refers to a group of diseases which are all caused by fungus called dermatophytes. Tinea can be spread by people after contact with towels, locker room floors, and so forth. This fungus can affect different parts of the body and cause symptoms specific to those regions, including:

• Ringworm, wherein the rash takes the form of a ring on the neck, arms, legs, or trunk
• Scalp ringworm
• Athlete’s foot
• Jock itch

Over-the-counter ointments and creams will usually treat tinea in the short term. More serious cases may require treatment with prescription medications.

Urticaria (Hives)

Clinical presentation: Wheals

Principal age group(s): All ages

Cause: Allergies to food or drugs

Course: Typically resolves after a few days or few weeks

Urticaria, or hives and angioedema typically occur together. Angioedema refers to the swelling of the skin. Urticaria is treated with steroids and antihistamines, as well as the removal of any drugs or foods that are causing it.

Varicella (Chickenpox)

Clinical presentation: Papules, vesicles, pustules, and crusting, spreading out from a center (i.e., centrifugal)

Principal age group(s): Children

Cause: Varicella zoster virus

Course: Transient, lasts two weeks

Initial infection with the varicella zoster virus typically occurs in children between 1 and 9 years old and results in chickenpox. In adults, the first-time infection with the virus is often more severe and accompanied by pneumonia.

The hallmark of diagnosis with the varicella virus is a vesicular rash, which begins as papules then changes into vesicles and pustules before finally crusting. The rash first involves the face, trunk, and scalp. Eventually, it moves toward the arms and legs. Other symptoms of chickenpox include headache, weakness, and loss of appetite.

Treatment of chickenpox is symptomatic, with acetaminophen given for fever; fluids given for hydration; and antihistamines, calamine lotion, and colloidal oatmeal baths applied to the skin. Antiviral therapy with acyclovir can reduce the duration of the fever and the severity of the symptoms. Childhood vaccination against chickenpox is recommended by the CDC.