An Alphabetical List of Rashes

A look at the presentation, causes, and course of 19 different rashes.

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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.

However, in the text Symptom to Diagnosis: An Evidence-Based Guide, Stern and co-authors state the following:

The risk with pattern recognition is that diagnostic hypotheses are heavily influenced by recent experience, rare diagnoses tend not to be recognized, and physicians often reach premature closure on an incorrect diagnosis.

In other words, even physicians can get the diagnosis of a rash wrong.

Before we look at an alphabetical list of different types of rash, 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 common terms used to describe rashes.

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

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 acne 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, also called atopic eczema, affects between 15 and 20 percent of children living in industrialized countries. It’s a very itchy skin condition and runs in families.

Mild cases of atopic dermatitis can be treated with topical steroids (glucocorticoids), which are 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 mucus membranes in older adults. Treatment of bullous pemphigoid is complex and requires input from various specialists, including dermatologists, ophthalmologists, and primary care physicians. Treatment depends on its spread, and topical steroids are usually effective. More severe cases may require treatment with immunomodulators such as topical tacrolimus.

Dermatitis Herpetiformis

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

Principal age group(s): Between 30 and 40 years

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

Dermatitis herpetiformis is a very 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. People with dermatitis herpetiformis also usually have gluten intolerance, and this rash appears in about 10 percent of people with celiac disease. It is more common in men and usually affects people of Northern European descent. Symptoms of dermatitis herpetiformis usually clear after consumption of a gluten-free diet.

Erythema Multiforme

Clinical presentation: Target lesions

Principal age group: Young adults

Cause: Allergic reaction

Course: Transient, 1 to 2 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 mutliforme 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. First, 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.

Here are some other symptoms that can 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 6 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 1 inch in diameter. These painful lumps may become purplish after a few days. After several weeks, these 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 infection of the hair follicle. It can be either on the surface and affect only the upper hair follicle. Or, folliculitis 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 also 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 WHO estimates that 3.7 billion people younger than 50 years old were infected with herpes simplex virus (HSV-1) in 2012. 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 11 percent of the world’s population is infected with genital herpes.

Herpes Zoster (Shingles)

Clinical presentation: Redness, vesicles

Cause: Varicella zoster virus reactivation

Principal age group(s): Elderly people

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, and called the shingles vaccine. The shingles vaccine 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 Stretptococcus 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 by practicing good personal hygiene and avoid sharing clothes and towels.

Lichen Simplex Chronicus

Clinical presentation: Plaques, lichenification

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

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

Cause: Unknown

Course: In 80 percent of people, the rash resolves in 8 weeks. Rarely, rash can persist between 3 and 5 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 4 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 that have silvery scales. Plaque psoriasis is the most common type of psoriasis, accounting for about 90 percent 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.

This condition affects about 3 percent of Americans. 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. However, 30 to 40 percent of all patients won't recount a tick bite, and many patients don’t experience rash.

With Rocky Mountain spotted fever, older children and adults first develop a headache which is 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 premethrin
  • 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 3 to 5 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. An estimated 14 million Americans have rosacea. It is an inflammatory condition that affects the face and the eyes and typically progresses over time. Rosacea can cause facial discomfort.

Over time 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 aged between 20 and 50

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

Cause: Fungus

Principal age group(s): All ages

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

Tinea refers to a group of diseases that 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 swelling of the skin. Hives occurs in 20 percent of the population at some point. About 0.5 percent of people have chronic, or long-term, urticaria, which is an autoimmune issue. Urticaria is treated with steroids and antihistamines as well as 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 and results in chickenpox. In adults, 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, the rash moves towards 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.

Sources:

Chapter 116. Impetigo. In: Usatine RP, Smith MA, Chumley HS, Mayeaux EJ, Jr.. eds. The Color Atlas of Family Medicine, 2e New York, NY: McGraw-Hill; 2013.

Culton DA, Liu Z, Diaz LA. Chapter 56. Bullous Pemphigoid. In: Goldsmith LA, Katz SI, Gilchrest BA, Paller AS, Leffell DJ, Wolff K. eds. Fitzpatrick's Dermatology in General Medicine, 8e New York, NY: McGraw-Hill; 2012.

Jaffe J, Ratcliff T. Chapter 42. Infectious Disease Emergencies. In: Stone C, Humphries RL. eds. CURRENT Diagnosis & Treatment Emergency Medicine, 7e New York, NY: McGraw-Hill; 2011.

Leung DM, Eichenfield LF, Boguniewicz M. Chapter 14. Atopic Dermatitis (Atopic Eczema). In: Goldsmith LA, Katz SI, Gilchrest BA, Paller AS, Leffell DJ, Wolff K. eds. Fitzpatrick's Dermatology in General Medicine, 8e New York, NY: McGraw-Hill; 2012.

Zaenglein AL, Graber EM, Thiboutot DM. Chapter 80. Acne Vulgaris and Acneiform Eruptions. In: Goldsmith LA, Katz SI, Gilchrest BA, Paller AS, Leffell DJ, Wolff K. eds. Fitzpatrick's Dermatology in General Medicine, 8e New York, NY: McGraw-Hill; 2012.

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