They usually occur on the thighs or legs but can occur anywhere. This photo shows a small hyperpigmented Vesicles are small, clear, fluid-filled blisters 10 mm in diameter.
Vesicles are characteristic of herpes infections, acute allergic contact dermatitis Allergic contact dermatitis ACD Contact dermatitis is inflammation of the skin caused by direct contact with irritants irritant contact dermatitis or allergens allergic contact dermatitis.
Symptoms include pruritus and Typical findings are clusters of intensely Dermatitis herpetiformis typically manifests as crops of vesicles. These may be caused by burns, bites, irritant contact dermatitis Irritant contact dermatitis ICD Contact dermatitis is inflammation of the skin caused by direct contact with irritants irritant contact dermatitis or allergens allergic contact dermatitis.
Classic autoimmune bullous diseases include pemphigus vulgaris Pemphigus Vulgaris Pemphigus vulgaris is an uncommon, potentially fatal, autoimmune disorder characterized by intraepidermal blisters and extensive erosions on apparently healthy skin and mucous membranes. Mucous membrane involvement is rare.
Diagnosis is by skin biopsy Bullae also may occur in inherited disorders of skin fragility. Bullous pemphigoid is characterized by eruptions of tense bullae on normal-appearing or reddened skin in elderly patients. Pustules are vesicles that contain pus.
Pustules are common in bacterial infections and folliculitis and may arise in some inflammatory disorders including pustular psoriasis Subtypes of Psoriasis Psoriasis is an inflammatory disease that manifests most commonly as well-circumscribed, erythematous papules and plaques covered with silvery scales. Pustules are elevated, usually yellow-topped lesions that contain pus. Scattered pustules appear on the face of this person with acne.
Urticaria Urticaria Urticaria consists of migratory, well-circumscribed, erythematous, pruritic plaques on the skin. Urticaria also may be accompanied by angioedema, which results from mast cell and basophil activation Wheals are pruritic and red.
Wheals are a common manifestation of hypersensitivity to drugs, stings or bites, autoimmunity, and, less commonly, physical stimuli including temperature, pressure, and sunlight. The typical wheal lasts 24 hours. Urticarial lesions wheals or hives are migratory, elevated, pruritic, reddish plaques caused by local dermal edema.
Scale is heaped-up accumulations of horny epithelium that occur in disorders such as psoriasis Psoriasis Psoriasis is an inflammatory disease that manifests most commonly as well-circumscribed, erythematous papules and plaques covered with silvery scales. The cause is unknown, but species of Malassezia, Pityriasis rosea Pityriasis Rosea Pityriasis rosea is a self-limited, inflammatory disease characterized by diffuse, scaling papules or plaques. Treatment is usually unnecessary.
Pityriasis rosea most commonly occurs between Scales are heaped-up accumulations of horny epithelium. Scaling is a characteristic feature of many dermatophytoses, including tinea capitis. In this image, it is especially noticeable at the nape of the neck. Crusts scabs consist of dried serum, blood, or pus. Crusting can occur in inflammatory or infectious skin diseases eg, impetigo Impetigo and Ecthyma Impetigo is a superficial skin infection with crusting or bullae caused by streptococci, staphylococci, or both.
Ecthyma is an ulcerative form of impetigo. Diagnosis is clinical. Treatment is Erosions are open areas of skin that result from loss of part or all of the epidermis.
Erosions can be traumatic or can occur with various inflammatory or infectious skin diseases. An excoriation is a linear erosion caused by scratching, rubbing, or picking. Ulcers result from loss of the epidermis and at least part of the dermis. Causes include venous stasis dermatitis Stasis Dermatitis Stasis dermatitis is inflammation, typically of the skin of the lower legs, caused by chronic edema.
Symptoms are itching, scaling, and hyperpigmentation. Ulceration can be a complication. They are caused Cutaneous vasculitis may be limited to the Petechiae are nonblanchable punctate foci of hemorrhage.
Causes include platelet abnormalities eg, thrombocytopenia, platelet dysfunction Overview of Platelet Disorders Platelets are cell fragments that function in the clotting system. Thrombopoietin helps control the number of circulating platelets by stimulating the bone marrow to produce megakaryocytes, Vasculitis can affect any blood vessel—arteries, arterioles, veins, venules, or capillaries Symptoms are high fever, severe headache, and rash.
See also Overview of Rickettsial Purpura is a larger area of hemorrhage that may be palpable. Palpable purpura is considered the hallmark of leukocytoclastic vasculitis. Purpura may indicate a coagulopathy. Large areas of purpura may be called ecchymoses or, colloquially, bruises. Atrophy is thinning of the skin, which may appear dry and wrinkled, resembling cigarette paper.
Drug reactions: If the maculopapular rash is a drug reaction, the doctor will have you stop the medication and try a substitute, if necessary. Infections: If the cause of the rash is a viral infection or a bacterial infection, you will be treated for the particular disease. For example, a maculopapular rash caused by the Zika virus has no specific treatment. In the case of Zika, you will be advised to rest, drink plenty of fluids, and use over-the-counter painkillers if necessary.
Allergic reactions: Topical steroid creams and wet wraps can help with inflamed skin. Your doctor may also prescribe antihistamines. Read more: How to treat an HIV rash ».
You may feel pain and itchiness due to the rash, but complications are unlikely to arise from the rash itself. What complications arise depend on the underlying cause. For example, you may develop life-threatening allergic reactions anaphylaxis with certain drugs, which causes a skin reaction. Or you may develop headaches, a stiff neck, or back pain from an infection. You may be particularly interested in the Zika virus, as the maculopapular rash is often associated with this virus.
The complications of the Zika virus can affect your baby , even if you had mild symptoms. The World Health Organization WHO has declared Zika a public health emergency because of the high incidence of microcephaly underdeveloped head size in babies born to women who had the rash in the first three months of their pregnancy.
Zika passes through mosquitoes or by having sex with someone who had the Zika virus. The WHO advises that pregnant women practice safe sex with condoms or abstain during the course of pregnancy.
There is a wide range of causes for this type of rash and a wide range of outcomes. Allergic reactions and minor reactions to drugs generally clear up quickly. Most childhood viral and bacterial infections have a known and limited course. Use medications as prescribed, including antihistamines and skin creams. Use insect repellant and take measures to eradicate mosquitoes in and around your neighborhood. Always follow up with your doctor if your rash is interfering with your day-to-day life.
The development of expertise in dermatology. Arch Dermatol. Dyer JA. Childhood viral exanthems. Pediatr Ann. Cotliar J.
Approach to the patient with a suspected drug eruption. Semin Cutan Med Surg. Fever and rash in a child: when to worry? Schlossberg D. Fever and rash. Infect Dis Clin North Am. Croskerry P. Achieving quality in clinical decision making: cognitive strategies and detection of bias. Acad Emerg Med. The generalized rash: Part II. Diagnostic approach. Am Fam Physician. Williams HC. Clinical practice. Atopic dermatitis. N Engl J Med.
Contact allergy in children referred for patch testing: North American Contact Dermatitis Group data, — Bigby M. Rates of cutaneous reactions to drugs.
Histopathology of drug-induced exanthems: is there a role in diagnosis of drug allergy? Curr Opin Allergy Clin Immunol. Clini-copathologic correlation in erythema multiforme and Stevens-Johnson syndrome.
The role of streptococcal infection in the initiation of guttate psoriasis. Keratosis pilaris rubra: a common but underrecognized condition. Eisen D. The vulvovaginal-gingival syndrome of lichen planus. The clinical characteristics of 22 patients. Lichen planus. One-year review of pityriasis rosea at the National Skin Centre, Singapore.
Ann Acad Med Singapore. Pathogenesis and clinical features of psoriasis. Clinical features of infants with primary human herpesvirus 6 infection exanthem subitum, roseola infantum. Atypical manifestations of tinea corporis. Detection of herpes simplex virus type 1, herpes simplex virus type 2 and varicella-zoster virus in skin lesions. J Clin Virol. Br J Dermatol. Clinical criteria for the diagnosis of bullous pemphigoid: a reevaluation according to immunoblot analysis of patient sera.
Medical pearl: dermatitis herpeti-formis—potential for confusion with eczema. Mucocutaneous manifestations in 22 consecutive cases of primary HIV-1 infection. Diagnosis, treatment, and long-term management of Kawasaki disease [published correction appears in Pediatrics. Habif TP. Clinical Dermatology. New York, NY: Mosby; Centers for Disease Control and Prevention. Reported cases of lyme disease. United States, Accessed January 19, Drage LA. Life-threatening rashes: dermatologic signs of four infectious diseases.
Mayo Clin Proc. Mycosis fungoides: the great imitator. Infant staphylococcal scalded skin syndrome, Ireland, —preliminary outbreak report. Euro Surveill. Histopathological and epidemiological characteristics of patients with erythema exudativum multiforme major, Stevens-Johnson syndrome and toxic epidermal necrolysis. Erythema multiforme major most often results from a drug reaction. Mucous membranes are always involved.
The eruption tends to become bullous and systemic symptoms, including fever and prostration, are present.
Eating may be complicated by cheilitis and stomatitis, and micturition may be difficult because of balanitis and vulvitis. Conjunctivitis may be severe and can lead to keratitis and ulceration. Lesions may also be found in the pharynx, larynx and trachea. Rarely, erythema multiforme major can be life-threatening and can progress to necrotizing tracheobronchitis, meningitis, blindness, sepsis and renal tubular necrosis. Secondary Syphilis. The rash of secondary syphilis can be diffuse, with localized eruptions often occurring on the head, neck, palms and soles.
The lesions are typically brownish-red or pink macules and papules, but they may be papulosquamous, pustular or acneiform. The eruption usually occurs two to six months after the primary infection and two to 10 weeks after the primary chancre.
Patients often present with acute constitutional symptoms, and asymptomatic flat-topped macules and papules mucous patches are commonly found on the oral and genital mucosa. Classic condyloma lata may also be found in the perineum. Meningococcemia, Rocky Mountain spotted fever and dengue fever—all potentially life-threatening infections—may initially present with erythematous maculopapular lesions before advancing to a petechial exanthem.
Petechial rashes warrant immediate evaluation to rule out severe, life-threatening illness. For proper assessment of an acutely ill patient with a petechial rash, the physician must be familiar with the common infectious and noninfectious etiologies.
Prompt, accurate diagnosis and early treatment can be life-saving in patients with meningococcemia, rickettsial infections and bacteremia. Meningococcal infections are a worldwide concern. These infections occur sporadically or in epidemics, most commonly in the midwinter months. The risk of meningococcal disease is highest in infants, asplenic patients, alcoholics and patients with a complement deficiency especially C5 to C8.
In some patients, the typical prodrome of cough, headache, sore throat, nausea and vomiting may be of short duration. Patients with acute meningococcemia appear ill and usually present with a characteristic petechial rash Figure 5 , a high, spiking fever, tachypnea, tachycardia and mild hypotension.
In the early stages of disease, the rash may be maculopapular. Chronic meningococcemia is a rare condition. Patients may present with intermittent rash, fever, arthritis and arthralgias occurring over a period of weeks to several months. In some patients, the chronic form advances to acute meningococcemia.
Rocky Mountain spotted fever is the most common rickettsial disease in the United States. The disease occurs most often in young men between April and September. The prodrome may include malaise, chills, a feverish feeling, anorexia and irritability.
The onset of symptoms may be abrupt, with the predominant features being fever 94 percent , severe headache 86 percent , generalized myalgia 83 percent , shaking rigor, photophobia, prostration and nausea. The diagnosis can be difficult when the onset is gradual and no rash is present, as is the case in up to 20 percent of adults and 5 percent of children with Rocky Mountain spotted fever. When rash is present, it develops on approximately the fourth day of illness. Its appearance, combined with the temporal evolution, is characteristic of Rocky Mountain spotted fever.
The rash typically begins as pink macules, 2 to 6 mm in diameter, located on the wrists, forearms, ankles, palms and soles. Within six to 18 hours, the rash spreads centrally to involve the arms, thighs, trunk and face.
In the ensuing one to three days, the lesions evolve into deep-red papules. Within two to four days after onset of the rash, the lesions become petechiae. Viral illnesses known to cause petechial rashes include coxsackievirus A9, echovirus 9, Epstein-Barr virus and cytomegalovirus infections, atypical measles and viral hemorrhagic fevers caused by arboviruses and arenaviruses.
Coxsackievirus and echovirus infections in children can produce severe illness and, at times, are difficult to distinguish from meningococcemia.
Included in the differential diagnosis of petechial rash are disseminated gonococcal infections, bacteremia, staphylococcemia and thrombotic thrombocytopenic purpura. Scarlet fever provides the classic example of an erythematous rash with subsequent desquamation.
Most common between one and 10 years of age, 18 scarlet fever usually follows an acute infection of the tonsils or skin by group A beta-hemolytic streptococci that produce an erythrogenic exotoxin. The rash begins as finely punctate erythema on the superior trunk and face two to three days after the onset of illness. The erythema quickly spreads to the extremities.
When present, petechiae in the antecubital and axillary skin folds Pastia's lines can be helpful in making the diagnosis. Initially, the tongue may appear white, with red, swollen papillae white strawberry tongue , but by the fourth or fifth day, it becomes bright red red strawberry tongue. The oral mucosa may have punctate erythema or petechiae, and the tonsils may be acutely infected. The exanthem varies in intensity. However, it usually fades in four to five days and is followed by diffuse desquamation.
The infection may be mild, and patients may present with only complaints of desquamation. Rarely, the streptococcal infection may produce a toxic-shock—like picture that results in hypotension and multisystem failure.
Many of these patients have a localized tissue infection that progresses to necrotizing fasciitis, which usually warrants immediate surgical intervention. Staphylococcus aureus is the organism responsible for classic toxic shock syndrome and scalded skin syndrome. Toxic shock syndrome can present with hypotension, erythema, fever and multisystem dysfunction.
Several different staphylococcal exotoxins have been implicated. The syndrome may result from infection, or it may occur because of simple colonization with S. The rash is usually diffuse and can present as bullous impetigo, scarlatiniform lesions or diffuse erythema Figure 6. The mucous membranes are spared in most patients. During the physical examination, the physician should attempt to elicit Nikolsky's sign shearing of the skin with gentle lateral pressure.
Kawasaki's disease, or mucocutaneous lymph node syndrome, is an acute febrile illness that affects infants and young children mean age: 2. The disease is uncommon after the age of 12 years. The fever lasts five to 30 days mean duration: 8. The rash appears within three days of the onset of fever and can vary in character. Frequently, the rash is scarlatiniform on the trunk and erythematous on the palms and soles, with subsequent distal desquamation. Mucous membrane involvement is common and includes hyperemic bulbar conjunctiva, injected oropharynx, dry, cracked lips and a strawberry tongue.
The physical examination may reveal non-suppurative cervical lymphadenopathy more than 1. Coronary artery abnormalities develop in 20 to 25 percent of patients with Kawasaki's disease. Ehrlichiosis, a rickettsial-like infection, can occasionally be associated with a clinical picture similar to toxic shock syndrome, including diffuse erythema. Streptococcus viridans bacteremia is another rare cause of generalized erythema.
Finally, enteroviral infections, toxic epidermal necrolysis, graft-versus-host reaction, erythroderma and generalized pustular psoriasis von Zumbusch's psoriasis may present with diffuse erythema. Varicella-zoster virus is the most infectious of the human herpesviruses. It is responsible for varicella chickenpox and herpes zoster shingles.
Primary infection with varicella-zoster virus results in chickenpox, a common childhood illness. Its highest incidence is in late winter and spring. The clinical presentation consists of rash, fever and general malaise. The rash typically begins on the face, scalp or trunk and then spreads to the extremities. The lesions appear as erythematous macules and progress to papules with an edematous base Figure 7.
An enanthema may be noted, and vesicles may evolve to shallow erosions, primarily on the palate. On physical examination, lesions in all stages may be present.
Complications are unusual in immunocompetent patients. In children, the most common complication is secondary bacterial infection of excoriated lesions. The central nervous system CNS is the most common site of extracutaneous involvement in children.
Cerebellar ataxia is the most frequently encountered syndrome. Other possible CNS complications include encephalitis, meningitis, transverse myelitis and, rarely, Reye's syndrome especially subsequent to aspirin use. Varicella pneumonia and encephalitis can be serious complications in adults. Additional rare complications in children and adults include myocarditis, corneal lesions, nephritis, arthritis, bleeding diatheses, acute glomerulonephritis and hepatitis. Herpes Zoster.
After the primary infection, the varicella-zoster virus lies dormant in the dorsal root ganglia. Herpes zoster is caused by reactivation of the virus.
An estimated 10 to 20 percent of the general U. The characteristic vesicular rash of herpes zoster usually affects a single dermatome and rarely crosses the midline Figure 8. The most common locations are the chest approximately 50 percent of cases and the face approximately 20 percent of cases. The rash begins as an erythematous maculopapular eruption that rapidly evolves to a vesicular rash.
Pain is the most debilitating feature of herpes zoster, and postherpetic neuralgia is the most common long-term complication. Post-herpetic neuralgia is uncommon in young patients but may affect as many as 50 percent of patients more than 50 years of age.
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