Heel fissures are splits or cracks in the epidermis, which can manifest as a consequence of anhidrosis and may or may not present with hyperkeratosis. Epidermal fissures are superficial and not considered to be a wound at this early stage. However, with increased pressure these splits become deeper, involving the dermis so that they begin to bleed and result in pain on weight-bearing activities. These fissures are regarded as partial-thickness skin wounds and are at increased risk of developing infection.
In Theory anyone can get a cracked heel or fissure soles but certain conditions predisposing to fissure soles are Congenital causes - Juvenile Plantar Dermatosis
Acquired causes - Eczema, Atopic Dermatitis, Tinea pedis,Psoriasis especially Palmoplantar psoriasis, Palmoplantar Keratodermas, Leprosy, Systemic causes-Diabetes mellitus, Hypothyroidism, Scleroderma, Rheumatoid arthritis.