They're red, they're round and they're really irritating. Annular skin rashes are those that manifest in a circular pattern. Skin rashes can be relatively benign, or they can be a symptom of a major systemic illness. Some skin rashes are common and easily identified, but more exotic disorders can be harder to diagnosis. Numerous factors can cause annular skin rashes. A consultation and examination by a dermatologist may be the only way to accurately determine the precise cause of an individual's rash.
This skin rash is caused by a fungal infection and can appear anywhere on the body. It causes itchy raised patches of skin that can have sharply defined borders. The outer perimeter of the circular rash may be darker red in color than the center, giving the rash a ring-like appearance, according to MedlinePlus.
This rash spreads in a scaly pattern of raised red circles that sweep outward from the central skin of the trunk and then downward, resembling the drooping of pine tree branches, according to MayoClinic.com. It is most common in children and young adults. The cause, though unclear, may be a viral infection.
Another annular skin rash whose cause is unknown, granuloma annulare typically covers the hands, feet, wrists and ankles with smooth, skin-colored or red papules or patches that take a circular form. It usually resolves on its own but may persist for up to two years before doing so, according to the American Academy of Family Physicians.
This inflammatory condition affects numerous organ systems in the body. It is characterized by inflammation of the lungs that can lead to scarring. DermNet NZ notes that It affects the skin in up to 35 percent of cases. The skin rashes caused by sarcoidosis can affect the shins, hands, elbows, wrists, face, fingers and toes. Their appearance varies from purple-red or brown annular rash to tender, small bumps, according to DermNet NZ.
Though rare in the United States, the American Academy of Family Physicians notes that leprosy still affects some people in Texas, Louisiana, Hawaii and California. Its appearance varies depending on the patient's immune response. In those with darker skin, the rashes may lack pigment. They can be scaly, red and sharply defined. These rashes are typically dry and hairless and may be numb, or insensitive, to stimuli.
Insects can spread bacteria through their bite. In cases of Lyme disease, ticks transmit the Borrelia burgdorferi bacteria to human hosts. Sometimes the immune system can ward off the infection, but in other people, the infection may result in a localized response or a systemic inflammatory disease.
A rash will typically appear within 10 days after a person has been bitten. It may have a bull's-eye appearance, with a center of normal skin surrounded by a red ring. This rash may initially appear as a single red patch and then spread to multiple areas of the skin. It is accompanied by flu-like symptoms, according to DermNet NZ.