ALA-iPDT for follicular occlusion tetrad concomitant with pachyonychia congenital type Ⅱ and ankylosing spondylitis.

The follicular occlusion tetrad is a complex dermatologic syndrome which can concomitant with other diseases. The case reported a young male patient suffer from follicular occlusion tetrad (acne conglobata, hidradenitis suppurativa, dissecting cellulitis of the scalp, and pilonidal sinuses) concomitant with pachyonychia congenital type Ⅱ (thickened nails, palmoplantar keratoderma, multiple cysts) and ankylosing spondylitis (lumbago, human leukocyte antigen-B27 positive). The genetic analysis showed the KRT17 gene mutation on exon 1 (c.T284C) supports the diagnosis. Whereupon, a comprehensive therapy scheme of 5-aminolevulinic acid-mediated interstitial photodynamic therapy (ALA-iPDT) combined with surgery offered excellent response. This case reports a rare condition and proposes a therapeutic option that may work.