When methicillin-resistant S. aureus (MRSA) is a concern, doxycycline or trimethoprim/sulfamethoxazole may, in addition, be recommended. There is concern related to the presence of pus or previous MRSA infections. Elevating the infected area may be useful, as may pain killers.Potential complications include abscess formation. Around 95% of people are better after 7 to 10 days of treatment. Those with diabetes, however, often have worse outcomes. Cellulitis occurred in about 21.2 million people in 2015. In the United States about 2 of every 1,000 people per year have a case affecting the lower leg. Cellulitis in 2015 resulted in about 16,900 deaths worldwide. In the United Kingdom, cellulitis was the reason for 1.6% of admissions to a hospital. Signs and symptoms
The typical signs and symptoms of cellulitis are an area that is red, hot, and painful. The photos shown here are of mild to moderate cases and are not representative of the earlier stages of the condition. Complications
Potential complications may include abscess formation, fasciitis, and sepsis. Causes
Cellulitis is caused by bacteria that enter and infect the tissue through breaks in the skin. Group A Streptococcus and Staphylococcus are the most common causes of the infection and may be found on the skin as normal flora in healthy individuals.About 80% of cases of Ludwigs angina, or cellulitis of the submandibular space, are caused by dental infections. Mixed infections, due to both aerobes and anaerobes, are commonly associated with this type of cellulitis.
About three-quarters of patients acquire PLE after UV-A exposure only, one-tenth after UV-B exposure only, and the rest after a combination of UV-A and UV-B exposure.People vary in the amount of sun exposure needed to trigger the rash. Oxidative stress
Oxidative stress and the modification of the redox status of the skin has been implicated in the expression of PLE. Photosensitizer
It has been suggested that an undefined endogenous or exogenous photo-allergen may trigger a delayed immune reaction resulting in PLE. Genetics
Half of patients have a family history of PLE, demonstrating a clear genetic influence. Oestrogen effect
The preponderance in women with a decline in severity following menopause has been thought to be associated with oestrogen effects, A natural fall in oestrogens may account for the tendency to remit after the menopause. Diagnosis
The diagnosis of PLE is typically made by assessing the history and clinical observations. Any investigations are usually to exclude other conditions, particularly lupus and porphyria.Blood tests are usually normal. However, positive antinuclear antibody and extractable nuclear antigen (anti-Ro/La) in low titre may be found, even in the absence of other criteria to suggest a diagnosis of lupus erythematosus. If clinical findings suggest a possibility of porphyria, urinary and red cell porphyrin screening may be performed and are negative in PLE.Photoprovocation tests are usually not required but may be undertaken by specialised centres in winter.