Common Skin Infections

Three 'Often Missed ' streptococcal diagnoses .

Perianal streptococcal cellulitis - quite common in children under age 10. Presents with perianal redness and soreness that may make defaecation painful. No systemic upset. Check skin swab for Streptococcus pyogenes. Responds to oral penicillin.

Streptococcal vulvo-vaginitis – usually caused by Strep. pyogenes presents as vulvo-vaginitis in pre-pubertal girls. Presents with genital soreness, dysuria and sometimes purulent discharge. Treatment - oral penicillin. Both the above can rarely occur in adults.

Blistering distal dactylitis -  A large blister/pustule on tip of a finger (palmar) esp in children/young adults - swab it - responds to oral penicillin.

Toxin mediated Staphylococcal and Streptococcal diseases.

The conditions which we have just seen and discussed are all due to direct invasion of the tissue by the bacterium. Both staphylococci and streptococci can cause pathology by toxins and we will have a look at these here. Although this is not discussed further at this stage in the course, remember too that Streptococcal throat infection may cause exacerbation of psoriasis by antigen cross linkage in the skin.