What is a Skin Rash?
A skin rash is an abnormal change in your skin’s color or texture,that is often red, dry/scaly and irritating/itchy. In darker skin types, rashes may cause your skin to appear darker in color (i.e. hyperpigmented) instead of red. Types of skin rashes are very numerous and may appear differently from person to person.
What causes Skin Rashes?
Skin rashes can be broadly classified into two general groups:
- Infectious skin rashes
- Non-infectious skin rashes
Infectious skin rashes are caused by infectious agents, such as bacteria, fungi or viruses.
Skin infections are variably contagious through direct skin-to-skin contact.
Fungi may cause a “skin rash” called tinea, including tinea versicolor at the site of infection. Chicken pox, shingles and viral exanthems are examples of virus-caused skin rashes. Interestingly, the skin rash of a viral exanthem is not contagious. Similarly, lichen planus is a non-contagious skin rash that is sometimes associated with viral hepatitis.
Non-infectious skin rashes represent a very large and diverse group of skin rashes, including the following conditions that we commonly encounter and treat:
- Allergic Dermatitis, such as contact and non-contact allergic dermatitis.
Contact dermatitis is a skin rash caused by direct skin contact with an allergen or irritant.
- Eczema (aka Atopic Dermatitis)
- Hives (Urticaria)
- Psoriasis and the similar, but rare skin rash pityriasis rubra pilaris
- Pityriasis Rosea
- Lichenoid dermatoses, including lichen planus, lichen sclerosus et atrophicus, skin lupus erythematosus
The causes of these non-infectious skin rashes are also very diverse, often multi-factorial and/or incompletely understood or unknown. Non-infectious skin rashes are not contagious.
Some possible causes or factors include environmental, genetic and nutritional influences, stress, immune system dysfunction, and/or other internal diseases/conditions, including cancer.
How are Skin Rashes diagnosed and treated?
Diagnosis of a skin rash starts with a dermatologic evaluation with examination. Adjunct testing, including skin sampling for pathology or culture, allergy testing, blood lab work-up and or addtional specialist consultation may be recommended.
Treatments broadly depend upon whether the skin rash is infectious or non-infectious in nature. Treatment for infections is directed at the type of infective agent, bacterial, fungal or viral.
Treatment of non-infectious skin rashes depends upon the casual factors and type of skin rash.
What is Allergic Dermatitis?
Allergic Dermatoses are also a broad, diverse group of skin rashes caused by an allergen.
An allergen is any substance that causes your body’s immune system to abnormally respond with an allergic reaction. An allergen does not promote an allergic response in everyone.
Any route that your body may interact with an allergen may produce an allergic reaction.
Contact dermatitis is a type of dermatitis that is caused by direct skin contact with an allergen or irritant. Poison ivy dermatitis is a classic example of allergic contact dermatitis. Polymorphic light eruption is a sensitivity to sunlight that causes a skin rash.
Others may be caused by oral ingestion of a medication, such as a drug skin reaction.
A medication-induced skin rash is a type of non-contact allergic dermatitis.
A dermatophytide type allergic skin rash is an allergic skin rash to an inflammatory fungal infection (tinea) located at a distant other skin site.
Hives (aka Urticaria) is another type of skin rash that may have an allergic cause, but often the cause of hives is unable to be determined.
Allergic Dermatoses are generally treated by removing and avoiding the offending agent, as well as anti-histamines and/or corticosteroid medications.
What is Eczema (Atopic Dermatitis)?
Eczema or atopic dermatitis is a very broad group of itchy, red skin rashes that are not characteristically caused by an allergen or other known cause.
Eczema is very common, affects all age groups and is often chronic (i.e. life long), but episodic. Seborrheic dermatitis is a type of eczema that preferentially affects the scalp, face and/or chest. Stasis dermatitis is an eczema of the lower legs caused by reduced venous circulatory function, often caused or promoted by other factors, including age, heredity and or prior deep venous blood clot or trauma..
The exact cause of eczema is unknown, however, environmental factors, such as dry skin promote eczema. Genetic predisposition is prevalent in many eczema patients.
Due to a lack of mature sebaceous glands (skin oil glands), eczema is very common in prepubescent children. Stress appears to be another aggravating factor. Some rare types of immune deficiency diseases may be associated with more severe eczema.
Diagnosis by a dermatologist is advised as eczema can appear similar to other types of skin rashes, including psoriasis, tinea, hives, scabies or cutaneous T-cell lymphoma (aka mycosis fungoides).
Treatment of eczema includes skin care recommendations aimed at improving hydration (moisturization) and barrier function, and reducing inflammation of your skin.
Medications for eczema that we may recommend or prescribe include topical non-steroid anti-inflammatories, topical and/or oral cortisone medications, and oral antihistamines and/or biologics (e.g. Dupixent).
Moisturizing your skin daily helps prevent or minimize future eczema outbreaks.
What are Hives (Urticaria)?
Hives or Urticaria is another type of skin rash characterized by very itchy “wheals” (aka hives). A hive is a superficial skin-colored/pale pink patch of swelling with or without a surrounding redness (erythema) that typically lasts minutes to less than 24 hours.
Urticaria can be sudden in onset and disappearance (acute) or more long-lasting, coming and going over many weeks to months (chronic).
Sometimes, a known trigger can be identified, such as a food, medication, insect bite or sting, latex, stress, or a physical stimulus such as heat/cold, sweat, pressure or sun exposure.
Urticaria is characterized by very itchy weals (hives), with or without surrounding erythematous flares. The name urticaria is derived from the common European stinging nettle Urtica dioica. Urticaria can be acute or chronic, spontaneous or inducible.
Urticaria can co-exist with angioedema which is a deeper swelling within the skin or mucous membranes.
Treatment of hives starts with avoiding triggers, if triggers are known and avoidable.
Medications for hives that we may recommend or prescribe include non-steroid anti-itch or anti-inflammatory topicals, topical and / or oral cortisone medications, oral antihistamines and or biologics [e.g. omalizumab (aka Xolair)].
What is Psoriasis?
Psoriasis is a non-contagious skin rash typically characterized by thick, red, scaly, well-delineated patchy skin areas that may or may not itch. Psoriasis is often bilateral and symmetrical and commonly affects knees and elbows, but may affect any cutaneous tissues, including nails. Psoriasis is a common, long-term (chronic) condition that typically waxes and wanes or cycles between episodes of flares and remissions. Although not curable, most patients are able to successfully manage this disease with one or more treatments offered by a dermatology provider.
Types of psoriasis include:
- Plaque psoriasis
- Inverse psoriasis
- Guttate psoriasis
- Pustular psoriasis
- Erythrodermic psoriasis
- Nail psoriasis
- Psoriatic arthritis
The exact cause of psoriasis is unknown, but immune system dysfunction that causes excessive skin regeneration and thus, rapid skin cell turnover is part of the cause. Genetic and environmental factors also contribute.
Psoriasis triggers may include: infections, cold and/or dry weather, injury or trauma, stress, smoking, alcohol and some medications or the withdrawal of some medications.
Risk factors for psoriasis include a family history of psoriasis, stress and smoking.
Diagnosis is by visual exam by a dermatology provider and or biopsy.
Treatment of psoriasis includes skin care recommendations aimed at improving hydration (moisturization) and barrier function, removing scales, slowing down excessive cell reproduction, and reducing inflammation of your skin.
Moisturizing your skin daily may help prevent or minimize future psoriasis outbreaks.
Treatments for psoriasis that we may recommend or prescribe include topical non-steroid anti-inflammatories (e.g. Vitamin D analogues and calcineurin inhibitors), topical and/or oral cortisone medications, oral antihistamines, methotrexate, biologics, and/or light therapy.
Strimling Dermatology, Laser & Vein Institute specializes in the diagnosis, treatment and management of psoriasis, including UVB-308 nm laser therapy.
Contact us at email@example.com or call us at (702) 243-6400 to schedule a consultation.