Folliculitis is an inflammatory process involving any part of the hair follicle.

Aetiology:

• it is most commonly secondary to infection (Bacteria, fungi, viruses, demodex mite)
  • Most common cause of superficial folliculitis - Staph aeurus
  • Gram negative (affects people treated with oral Abx) - Klebsiella, enterobacter, proteus
  • Pseudomonas aeruginosa - causes hot tub folliculitis
  • Fungal - dermatophytes, malassezia, candida
  • Viruses - HSV, VSV, Molluscum contagiosum
• Non infectious causes - Eosinophillic folliculitis
• Folliculitis primarily affecting the scalp - Folliculitis decalvans

Pathophysiology:

In superficial Staphylococcus aureus folliculitis, a predominantly neutrophilic cell population infiltrates the infundibular portion of the hair follicle

Risk factors:

• Trauma, including shaving and extraction
• topical corticosteroid preparations
• diabetes mellitus - Staphylococcus folliculitis
• immunosuppression
• Systemic abx - Gram negative folliculitis

PC

• pruritic/irritated erythematous popular/pustular rash in areas of hair growth
  • Itchy/sore, may form boils or carbuncles
• Umbilicated flesh-coloured papules - suggestive of molluscum contagiosum