Generalized and Localized Rashes

Overview

Definition

A rash Rash Rocky Mountain Spotted Fever is an abnormal change in the skin Skin The skin, also referred to as the integumentary system, is the largest organ of the body. The skin is primarily composed of the epidermis (outer layer) and dermis (deep layer). The epidermis is primarily composed of keratinocytes that undergo rapid turnover, while the dermis contains dense layers of connective tissue. Skin: Structure and Functions’s color or texture Texture Dermatologic Examination.

Epidemiology

• One of the most common conditions encountered by primary care physicians Physicians Individuals licensed to practice medicine. Clinician–Patient Relationship
• In 2016, 1 in 4 people in the United States (84.5 million) were affected by skin Skin The skin, also referred to as the integumentary system, is the largest organ of the body. The skin is primarily composed of the epidermis (outer layer) and dermis (deep layer). The epidermis is primarily composed of keratinocytes that undergo rapid turnover, while the dermis contains dense layers of connective tissue. Skin: Structure and Functions disease.
• 1 in 3 people required a dermatology evaluation.
• Maculopapular Maculopapular Dermatologic Examination rashes are the most commonly seen generalized rash Rash Rocky Mountain Spotted Fever (95%).
• Diagnostic errors Diagnostic Errors Incorrect or incomplete diagnoses following clinical or technical diagnostic procedures. Patient Safety: Types of Medical Errors in generalized rashes are common.

Etiology

The list of etiologies for rashes is long but can include irritants, allergens, infections Infections Invasion of the host organism by microorganisms or their toxins or by parasites that can cause pathological conditions or diseases. Chronic Granulomatous Disease, and inflammatory conditions.

Classification

Rashes are described and classified based on certain characteristics, which can assist with forming a differential diagnosis when evaluating a patient.

Configuration

The configuration refers to the shape or outline of lesions.  

• Circinate: round, circular
• Arciform: forms a partial circle
• Linear: appears straight 
• Serpiginous: meandering appearance
• Annular Annular Dermatologic Examination: round or circular with central clearing  
• Target: a series of concentric rings 
• Gyrate: a series of connecting arcs  
• Zosteriform: appears to follow a dermatome Dermatome Spinal Disk Herniation

Morphology

The morphology is based on the size and consistency Consistency Dermatologic Examination of the lesions.

• Flat lesions:
  • Macule: nonpalpable lesion < 1 cm in diameter
  • Patch: nonpalpable lesion > 1 cm in diameter
• Raised lesions:
  • Papule: elevated lesion < 1 cm in diameter
  • Plaque Plaque Primary Skin Lesions: flat-topped elevated lesion > 1 cm in diameter
  • Nodule Nodule Chalazion: deep, solid or cystic Cystic Fibrocystic Change, elevated lesion > 1 cm in diameter 
  • Wheal Wheal Urticaria (Hives): irregularly shaped, edematous, raised, transient plaque Plaque Primary Skin Lesions
• Blistering lesions:
  • Vesicle Vesicle Primary Skin Lesions: blister Blister Bullous Pemphigoid and Pemphigus Vulgaris filled with clear fluid, < 1 cm diameter
  • Bulla: blister Blister Bullous Pemphigoid and Pemphigus Vulgaris filled with fluid, > 1 cm diameter
  • Pustule: blister Blister Bullous Pemphigoid and Pemphigus Vulgaris filled with pus
• Disruption of the epidermis Epidermis The external, nonvascular layer of the skin. It is made up, from within outward, of five layers of epithelium: (1) basal layer (stratum basale epidermidis); (2) spinous layer (stratum spinosum epidermidis); (3) granular layer (stratum granulosum epidermidis); (4) clear layer (stratum lucidum epidermidis); and (5) horny layer (stratum corneum epidermidis). Skin: Structure and Functions:
  • Erosion: partial-thickness loss of the epidermis Epidermis The external, nonvascular layer of the skin. It is made up, from within outward, of five layers of epithelium: (1) basal layer (stratum basale epidermidis); (2) spinous layer (stratum spinosum epidermidis); (3) granular layer (stratum granulosum epidermidis); (4) clear layer (stratum lucidum epidermidis); and (5) horny layer (stratum corneum epidermidis). Skin: Structure and Functions
  • Fissure: a crack Crack The purified, alkaloidal, extra-potent form of cocaine. It is smoked (free-based), injected intravenously, and orally ingested. Use of crack results in alterations in function of the cardiovascular system, the autonomic nervous system, the central nervous system, and the gastrointestinal system. The slang term ‘crack’ was derived from the crackling sound made upon igniting of this form of cocaine for smoking. Cocaine Use Disorder or split that extends into the dermis Dermis A layer of vascularized connective tissue underneath the epidermis. The surface of the dermis contains innervated papillae. Embedded in or beneath the dermis are sweat glands; hair follicles; and sebaceous glands. Skin: Structure and Functions
  • Ulcer: full-thickness loss of the epidermis Epidermis The external, nonvascular layer of the skin. It is made up, from within outward, of five layers of epithelium: (1) basal layer (stratum basale epidermidis); (2) spinous layer (stratum spinosum epidermidis); (3) granular layer (stratum granulosum epidermidis); (4) clear layer (stratum lucidum epidermidis); and (5) horny layer (stratum corneum epidermidis). Skin: Structure and Functions that extends into the dermis Dermis A layer of vascularized connective tissue underneath the epidermis. The surface of the dermis contains innervated papillae. Embedded in or beneath the dermis are sweat glands; hair follicles; and sebaceous glands. Skin: Structure and Functions

Secondary characteristics

• Crust Crust Dried exudate of body fluids (blood, pus, or sebum) on an area of damaged skin Secondary Skin Lesions: dried exudate Exudate Exudates are fluids, cells, or other cellular substances that are slowly discharged from blood vessels usually from inflamed tissues. Pleural Effusion on the skin Skin The skin, also referred to as the integumentary system, is the largest organ of the body. The skin is primarily composed of the epidermis (outer layer) and dermis (deep layer). The epidermis is primarily composed of keratinocytes that undergo rapid turnover, while the dermis contains dense layers of connective tissue. Skin: Structure and Functions
• Scale Scale Dermatologic Examination: flakes or plates of desiccated epidermis Epidermis The external, nonvascular layer of the skin. It is made up, from within outward, of five layers of epithelium: (1) basal layer (stratum basale epidermidis); (2) spinous layer (stratum spinosum epidermidis); (3) granular layer (stratum granulosum epidermidis); (4) clear layer (stratum lucidum epidermidis); and (5) horny layer (stratum corneum epidermidis). Skin: Structure and Functions
• Lichenification Lichenification Atopic Dermatitis (Eczema): leathery thickening of the skin Skin The skin, also referred to as the integumentary system, is the largest organ of the body. The skin is primarily composed of the epidermis (outer layer) and dermis (deep layer). The epidermis is primarily composed of keratinocytes that undergo rapid turnover, while the dermis contains dense layers of connective tissue. Skin: Structure and Functions with exaggerated skin Skin The skin, also referred to as the integumentary system, is the largest organ of the body. The skin is primarily composed of the epidermis (outer layer) and dermis (deep layer). The epidermis is primarily composed of keratinocytes that undergo rapid turnover, while the dermis contains dense layers of connective tissue. Skin: Structure and Functions markings
• Excoriation Excoriation Mastitis: linear skin Skin The skin, also referred to as the integumentary system, is the largest organ of the body. The skin is primarily composed of the epidermis (outer layer) and dermis (deep layer). The epidermis is primarily composed of keratinocytes that undergo rapid turnover, while the dermis contains dense layers of connective tissue. Skin: Structure and Functions erosions Erosions Corneal Abrasions, Erosion, and Ulcers, often caused by scratching
• Edema Edema Edema is a condition in which excess serous fluid accumulates in the body cavity or interstitial space of connective tissues. Edema is a symptom observed in several medical conditions. It can be categorized into 2 types, namely, peripheral (in the extremities) and internal (in an organ or body cavity). Edema: swelling Swelling Inflammation of the tissue
• Scar Scar Dermatologic Examination: fibrous Fibrous Fibrocystic Change tissue development after an injury

Distribution

• Localized: Lesions are confined to a specific area.
• Generalized: Lesions are dispersed throughout the body.
• Symmetric: similarly affects both sides of the body
• Asymmetric: unilateral or affects both sides of the body differently
• Discrete: separate, distinct lesions
• Grouped: clusters of lesions
• Confluent (coalescing): Smaller lesions merge together.
• Cleavage plane: Lesions are arranged along the lines of skin Skin The skin, also referred to as the integumentary system, is the largest organ of the body. The skin is primarily composed of the epidermis (outer layer) and dermis (deep layer). The epidermis is primarily composed of keratinocytes that undergo rapid turnover, while the dermis contains dense layers of connective tissue. Skin: Structure and Functions tension.

Clinical Presentation and Diagnosis

The diagnosis for many conditions is purely clinical and based on the patient’s history and physical exam.

History

• Onset (including the location of initial onset)
• Time frame:
  • Acute or chronic
  • Relapsing-remitting
• Progression
• Aggravating and alleviating factors
• Associated symptoms:
  • Fever Fever Fever is defined as a measured body temperature of at least 38°C (100.4°F). Fever is caused by circulating endogenous and/or exogenous pyrogens that increase levels of prostaglandin E2 in the hypothalamus. Fever is commonly associated with chills, rigors, sweating, and flushing of the skin. Fever
  • Pruritus Pruritus An intense itching sensation that produces the urge to rub or scratch the skin to obtain relief. Atopic Dermatitis (Eczema)
  • Pain Pain An unpleasant sensation induced by noxious stimuli which are detected by nerve endings of nociceptive neurons. Pain: Types and Pathways
  • Malaise Malaise Tick-borne Encephalitis Virus
  • Cough
• Other pertinent history:
  • Allergies Allergies A medical specialty concerned with the hypersensitivity of the individual to foreign substances and protection from the resultant infection or disorder. Selective IgA Deficiency
  • Recent travel
  • Insect, plant, or animal exposure
  • Occupational history
  • New home products
  • Drug exposure
  • Sick contacts
  • Chronic illnesses
  • Sexual history

Physical exam

A full skin Skin The skin, also referred to as the integumentary system, is the largest organ of the body. The skin is primarily composed of the epidermis (outer layer) and dermis (deep layer). The epidermis is primarily composed of keratinocytes that undergo rapid turnover, while the dermis contains dense layers of connective tissue. Skin: Structure and Functions exam should be performed.

• Appearance:
  • Number of lesions
  • Configuration and borders
  • Morphology
  • Color
  • Presence of scale Scale Dermatologic Examination or crusts
• Distribution:
  • Diffuse or localized
  • Symmetrical Symmetrical Dermatologic Examination or asymmetrical
  • Dermatomal Dermatomal Dermatologic Examination
  • Clustered or grouped
  • Mucosal involvement
  • Atypical sites (e.g., palms and soles)
• Palpation Palpation Application of fingers with light pressure to the surface of the body to determine consistency of parts beneath in physical diagnosis; includes palpation for determining the outlines of organs. Dermatologic Examination of lesions:
  • Raised
  • Flat
  • Texture Texture Dermatologic Examination changes
  • Induration Induration Dermatologic Examination
  • Blanching Blanching Dermatologic Examination with pressure
• In patients Patients Individuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures. Clinician–Patient Relationship with bullae Bullae Erythema Multiforme, check for Nikolsky sign Nikolsky Sign Dermatologic Examination:
  • Extension Extension Examination of the Upper Limbs of skin Skin The skin, also referred to as the integumentary system, is the largest organ of the body. The skin is primarily composed of the epidermis (outer layer) and dermis (deep layer). The epidermis is primarily composed of keratinocytes that undergo rapid turnover, while the dermis contains dense layers of connective tissue. Skin: Structure and Functions blistering or sloughing by applying pressure
  • Demonstrates skin Skin The skin, also referred to as the integumentary system, is the largest organ of the body. The skin is primarily composed of the epidermis (outer layer) and dermis (deep layer). The epidermis is primarily composed of keratinocytes that undergo rapid turnover, while the dermis contains dense layers of connective tissue. Skin: Structure and Functions detachment
• In patients Patients Individuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures. Clinician–Patient Relationship with plaques, check for Auspitz sign Auspitz Sign Psoriasis: pinpoint bleeding after scraping plaques
• Other physical exam findings to evaluate for:
  • Vital signs
  • Lymphadenopathy Lymphadenopathy Lymphadenopathy is lymph node enlargement (> 1 cm) and is benign and self-limited in most patients. Etiologies include malignancy, infection, and autoimmune disorders, as well as iatrogenic causes such as the use of certain medications. Generalized lymphadenopathy often indicates underlying systemic disease. Lymphadenopathy
  • Conjunctivitis Conjunctivitis Conjunctivitis is a common inflammation of the bulbar and/or palpebral conjunctiva. It can be classified into infectious (mostly viral) and noninfectious conjunctivitis, which includes allergic causes. Patients commonly present with red eyes, increased tearing, burning, foreign body sensation, and photophobia. Conjunctivitis
  • Pharyngitis Pharyngitis Pharyngitis is an inflammation of the back of the throat (pharynx). Pharyngitis is usually caused by an upper respiratory tract infection, which is viral in most cases. It typically results in a sore throat and fever. Other symptoms may include a runny nose, cough, headache, and hoarseness. Pharyngitis
  • Heart murmur
  • Hepatosplenomegaly Hepatosplenomegaly Cytomegalovirus
  • Joint swelling Swelling Inflammation
  • Neurologic deficits Neurologic Deficits High-Risk Headaches

Testing

A diagnostic workup may be performed if the history and physical exam do not provide enough clues to the diagnosis. The differential diagnosis will dictate which studies should be performed.

• Biopsy Biopsy Removal and pathologic examination of specimens from the living body. Ewing Sarcoma with microscopic examination:
  • There are no widely accepted guidelines with indications for skin biopsy Skin Biopsy Secondary Skin Lesions.
  • Immunofluorescence can be helpful.
• Laboratory tests are indicated if there are systemic symptoms.
  • CBC → evaluate for eosinophilia Eosinophilia Abnormal increase of eosinophils in the blood, tissues or organs. Autosomal Dominant Hyperimmunoglobulin E Syndrome, neutrophilia, or thrombocytopenia Thrombocytopenia Thrombocytopenia occurs when the platelet count is < 150,000 per microliter. The normal range for platelets is usually 150,000-450,000/µL of whole blood. Thrombocytopenia can be a result of decreased production, increased destruction, or splenic sequestration of platelets. Patients are often asymptomatic until platelet counts are < 50,000/µL. Thrombocytopenia
  • Basic metabolic panel Basic Metabolic Panel Primary vs Secondary Headaches and liver Liver The liver is the largest gland in the human body. The liver is found in the superior right quadrant of the abdomen and weighs approximately 1.5 kilograms. Its main functions are detoxification, metabolism, nutrient storage (e.g., iron and vitamins), synthesis of coagulation factors, formation of bile, filtration, and storage of blood. Liver: Anatomy function panel → evaluate for systemic renal and hepatic involvement
  • ANAs → a good initial test if an autoimmune etiology is being considered
  • Serologic testing for various infectious causes
• Allergy Allergy An abnormal adaptive immune response that may or may not involve antigen-specific IgE Type I Hypersensitivity Reaction testing:
  • Patch testing
  • Skin Skin The skin, also referred to as the integumentary system, is the largest organ of the body. The skin is primarily composed of the epidermis (outer layer) and dermis (deep layer). The epidermis is primarily composed of keratinocytes that undergo rapid turnover, while the dermis contains dense layers of connective tissue. Skin: Structure and Functions prick testing
  • Serum IgE IgE An immunoglobulin associated with mast cells. Overexpression has been associated with allergic hypersensitivity. Immunoglobulins: Types and Functions studies

Management

The management of a rash Rash Rocky Mountain Spotted Fever depends on the underlying condition. Many rashes will be self-limited and may not require any treatment.

• Basic management:
  • Identify and avoid aggravating factors.
  • Supportive therapies:
    • Low-heat baths
    • Mild soaps
    • Emollients Emollients Oleaginous substances used topically to soothe, soften or protect skin or mucous membranes. They are used also as vehicles for other dermatologic agents. Pityriasis Rosea
    • Skin Skin The skin, also referred to as the integumentary system, is the largest organ of the body. The skin is primarily composed of the epidermis (outer layer) and dermis (deep layer). The epidermis is primarily composed of keratinocytes that undergo rapid turnover, while the dermis contains dense layers of connective tissue. Skin: Structure and Functions moisturizers
• Symptom management for pain Pain An unpleasant sensation induced by noxious stimuli which are detected by nerve endings of nociceptive neurons. Pain: Types and Pathways and pruritus Pruritus An intense itching sensation that produces the urge to rub or scratch the skin to obtain relief. Atopic Dermatitis (Eczema):
  • Acetaminophen Acetaminophen Acetaminophen is an over-the-counter nonopioid analgesic and antipyretic medication and the most commonly used analgesic worldwide. Despite the widespread use of acetaminophen, its mechanism of action is not entirely understood. Acetaminophen
  • NSAIDs NSAIDS Primary vs Secondary Headaches
  • Antihistamines Antihistamines Antihistamines are drugs that target histamine receptors, particularly H1 and H2 receptors. H1 antagonists are competitive and reversible inhibitors of H1 receptors. First-generation antihistamines cross the blood-brain barrier and can cause sedation. Antihistamines
• For inflammatory conditions:
  • Infection should be ruled out.
  • Topical steroids Steroids A group of polycyclic compounds closely related biochemically to terpenes. They include cholesterol, numerous hormones, precursors of certain vitamins, bile acids, alcohols (sterols), and certain natural drugs and poisons. Steroids have a common nucleus, a fused, reduced 17-carbon atom ring system, cyclopentanoperhydrophenanthrene. Most steroids also have two methyl groups and an aliphatic side-chain attached to the nucleus. Benign Liver Tumors:
    • Hydrocortisone Hydrocortisone The main glucocorticoid secreted by the adrenal cortex. Its synthetic counterpart is used, either as an injection or topically, in the treatment of inflammation, allergy, collagen diseases, asthma, adrenocortical deficiency, shock, and some neoplastic conditions. Immunosuppressants
    • Triamcinolone Triamcinolone A glucocorticoid given, as the free alcohol or in esterified form, orally, intramuscularly, by local injection, by inhalation, or applied topically in the management of various disorders in which corticosteroids are indicated. Glucocorticoids
    • Clobetasol Clobetasol A derivative of prednisolone with high glucocorticoid activity and low mineralocorticoid activity. Absorbed through the skin faster than fluocinonide, it is used topically in treatment of psoriasis but may cause marked adrenocortical suppression. Glucocorticoids
    • Betamethasone Betamethasone A glucocorticoid given orally, parenterally, by local injection, by inhalation, or applied topically in the management of various disorders in which corticosteroids are indicated. Its lack of mineralocorticoid properties makes betamethasone particularly suitable for treating cerebral edema and congenital adrenal hyperplasia. Glucocorticoids
  • Systemic steroids Steroids A group of polycyclic compounds closely related biochemically to terpenes. They include cholesterol, numerous hormones, precursors of certain vitamins, bile acids, alcohols (sterols), and certain natural drugs and poisons. Steroids have a common nucleus, a fused, reduced 17-carbon atom ring system, cyclopentanoperhydrophenanthrene. Most steroids also have two methyl groups and an aliphatic side-chain attached to the nucleus. Benign Liver Tumors
• For infectious causes:
  • Antibiotics
  • Antifungals
  • Antivirals
• Appropriate management for underlying systemic conditions

Comparison of Generalized Rashes

Noninfectious conditions

Infectious conditions

Comparison of Common Localized Rashes