Wednesday, April 28, 2021
Monday, April 12, 2021
|MORPHOLOGY OF ALLERGIC CONTACT DERMATITIS|
|INFANTS AND CHILDREN WITH ATOPIC DERMATITIS|
|PATHOPHYSIOLOGY OF AUTOINFLAMMATORY SYNDROMES|
Sunday, April 11, 2021
Monday, March 8, 2021
Syphilis has been well described in the literature since the late 1400s. The history behind the discovery and treatment of the disease is a story of perseverance and the willpower of many scientists working separately and together to help treat one the most deadly diseases of their time. Philip Ricord, a French scientist, is given credit for describing the three stages of syphilis and differentiating it from other diseases such as gonorrhea. The infectious organism, Treponema pallidum, was described in 1905 by Fritz Schaudinn, a German zoologist, and Erich Hoffman, a German dermatologist. Soon after this discovery, the German scientist Paul Ehrlich developed the first specific therapy for syphilis. The oral medication he and his team discovered was initially called 606, because it was the 606th compound they had attempted to use to treat the disease. This organoarsenic molecule was soon renamed salvarsan. This medication is highly effective against T. pallidum.
Androgenic alopecia, also known as male pattern baldness or female pattern hair loss, is a major form of hair loss. The age at onset is variable and likely has a genetic determination. Some men lose their entire scalp hair, resulting in baldness. Baldness is rare in women, because their hair loss manifests as varying grades of thinning.
Alopecia areata is an autoimmune disease that causes discrete circular or oval areas of nonscarring alopecia. This form of alopecia has several clinical variants, including alopecia totalis, alopecia universalis, and an ophiasis pattern. Therapy is often difficult. The disease can have profound psychological impact, especially in young patients. It is critical to address this issue, because the effects on the patient’s psychological well-being are often more severe than the actual hair loss.
Verrucae are one of the most frequently encountered viral infections in humans. They are capable of causing disease in any individual, but severe infections seem to be more likely in those who are immunocompromised. Warts can affect any cutaneous surface, and unique wart subtypes are more prone to cause disease in different clinical locations. By far the most important aspect of infection with the human papillomavirus (HPV) is the ability of the virus to cause malignant transformation. This malignant potential is specific to certain subtypes and is especially a concern in women, who are at risk for cervical cancer. Most cases of cervical cancer can be traced to prior infection with certain HPV strains. In June 2006, the U.S. Food and Drug Administration approved the use of a prophylactic HPV vaccine in prepubertal girls. The vaccine is a recombinant quad-rivalent vaccine against HPV types 6, 11, 16, and 18. Types 16 and 18 are believed to have been responsible for up to 70% of cervical cancers.
HERPES ZOSTER (SHINGLES)
The varicella zoster virus (VZV) is responsible for causing varicella (chickenpox) as well as herpes zoster (shingles). Herpes zoster is caused by reactivation of dormant VZV. Only hosts who have previously been infected with VZV can develop herpes zoster. The incidence of herpes zoster is sure to decrease in the future, because the zoster vaccine has good efficacy in increasing immunity against the virus. The live attenuated vaccine is currently recommended for those individuals 60 years of age and older who fulfill the criteria for receiving a live vaccine. This age was chosen because the incidence of herpes zoster increases after age 60, possibly related to a waning immune response and anti-body titer remaining from the patient’s original VZV infection. Whether the VZV vaccine protects against herpes zoster will take years to determine. The United States introduced widespread childhood immunization against VZV in 1995, and none of these children have yet reached the age of 60. Whether future booster vaccinations or VZV revaccination will be required is yet to be determined.
The varicella-zoster virus (VZV) causes two discrete clinical infections: chickenpox (varicella) and herpes zoster (shingles). Although chickenpox was once a universal infection of childhood, the incidence of this disease has plummeted since the advent of the chickenpox vaccine. VZV belongs to the herpesvirus family and is primarily a respiratory disease with skin manifestations.
Wednesday, February 17, 2021
STAPHYLOCOCCUS AUREUS SKIN INFECTIONS
Cutaneous infection with Staphylococcus aureus can manifest in many ways. With the emergence of methicillin-resistant S. aureus (MRSA), these cutaneous infections have once again been given the attention they deserve. Most cases of MRSA are community acquired, and they have entirely different sensitivity patterns than those of hospital-acquired MRSA infections. These cutaneous infections are increasing in incidence. They not only cause significant skin disease but have the potential to become systemic and cause septicemia, pneumonia, osteomyelitis, and other internal infections. S. aureus is a transient colonizer of the skin and nasopharynx. This bacteria has shown a remarkable ability to develop and acquire antibacterial resistance mechanisms. S. aureus and MRSA are major hospital-acquired S. aureus infections, and now community-acquired MRSA has become just as important. MRSA accounts for more than 50% of hospital-acquired S. aureus infections.
Sporothrix schenckii is an environmental fungus that is capable of causing human disease after direct inoculation into the skin. Inoculation is the cause of cutaneous sporotrichosis, which is considered to be a subcutaneous mycosis. Unusual cases of inhalation sporotrichosis have been described in the literature, as have cases of central nervous system disease. These cases occur almost exclusively in immunosuppressed hosts. Sporotrichosis has classically been associated with inoculation after the prick from a rose plant. This is well reported; the fungus can be isolated from rose plants but is also found on many other plants and in soil environments. Clinical Findings: Gardeners, florists, and outdoor enthusiasts are at highest risk for infection from S. schenckii. These activities and occupations increase the likelihood of contact with the soil fungus. The fungus lives in the environment, and humans become infected by direct implantation of the fungus into the skin. Common methods of inoculation are the prick of a thorn or an injury contaminated with soil or plant mate- rial. Within a few days after entry into the skin, a papule and then a pustule form at the site of inoculation. Patients may initially be given an antibiotic in the belief that they have a bacterial infection. Often, it is not until the pustule ulcerates and develops into a larger plaque that the diagnosis is suspected or considered. Once this has occurred, the fungus enters the local lymphatics and proceeds to migrate proximally. As the fungus travels through the lymphatic system, it periodically causes draining sinus tracts to the surface, which appear as papules or nodules. This characteristic lymphangitic spread, also called sporotrichoid spread, is seen in most cases of cutaneous sporotrichosis.
Paracoccidioidomycosis, also known as South American blastomycosis, is a disease that is seen almost exclusively in regions of Central and South America. It is caused by the dimorphic fungus, Paracoccidioides brasiliensis. Most infections are acquired by direct inhalation of the chlamydospores. The fungus is found in the environment in the mycelial or mold phase; it converts to the yeast phase at body temperature. Brazil has the highest incidence of paracoccidioidomycosis. Primary lung infection may lead to disseminated disease, with the skin being secondarily infected. Direct inoculation into the skin causes primary cutaneous disease.
As its name implies, molluscum contagiosum is a highly contagious viral infection that has little morbidity. This infection is most commonly encountered in children. The diagnosis is made on clinical grounds after inspection of the characteristic skin findings. When seen in the genital region of adults, molluscum contagiosum is considered to be a sexually transmitted disease. This infection rarely occurs in immunocompetent adults outside sexual transmission. In adults with no clear evidence of transmission, an evaluation for an immunosuppressed state should be undertaken. Patients taking chronic immunosuppressive medications and those with the acquired immunodeficiency syndrome are more prone to infection with molluscum contagiosum.
Tuesday, February 16, 2021
Meningococcemia can cause a wide range of clinical diseases, of which neisserial meningitis is the most severe and life-threatening. The bacteria, Neisseria meningitidis, is capable of causing septicemia, pneumonia, and meningitis. These are all relentless diseases that are universally fatal if not promptly treated. The bacteria has been known to cause severe disseminated intravascular coagulation (DIC) and the Waterhouse-Friderichsen syndrome. The latter syndrome, also known as acute adrenocortical insufficiency, is directly caused by hemorrhagic destruction of both adrenal glands. This syndrome can result from a wide range of conditions, including infections, and N. meningitidis is one of the more frequent infectious causes.
Wednesday, February 10, 2021
Lymphogranuloma venereum (LGV) is a sexually transmitted disease (STD) that is produced by infection with Chlamydia trachomatis serotypes L1, L2, and L3. The disease progresses through three distinct phases of transmission. This bacterial disease was once limited to tropical regions, but with the ease of worldwide travel, it can now be seen globally. The skin manifestations are found predominantly in the groin and genital region. This disease is often seen in conjunction with other STDs, and screening for other STDs should be done routinely in patients diagnosed with LGV.