[Palmoplantar dermatoses: when should genes be considered?]

[Palmoplantar dermatoses in children]

Dermatoses of the hands and feet cover a wide range of skin diseases that can occur in children and adolescents and are a frequent question in dermatological practice. Our synopsis of the most important differential diagnoses and their treatment is intended to provide better orientation for daily practice. A precise and detailed history is essential to establish a diagnosis, followed by clinical examination and specific examination methods. Cutaneous infection should always be excluded, as they occur very frequently. Impetigo, punctate keratolysis, blistering distal dactylitis, tinea manuum and pedum, hand-foot-mouth disease, herpes simplex digitalis and verrucae vulgaris as well as scabies are often found in the palmoplantar area and typically affect children and adolescents. In case of allergic contact dermatitis and dyshidrotic eczema, atopic diathesis in the medical history is of importance. However, we must not miss rare causes. Palmoplantar keratoses, for example, can be due to inflammatory dermatoses like pityriasis rubra pilaris (PRP) or may, as well as blistering diseases, result from hereditary disorders. Specialised centers can perform molecular genetic diagnosis and enhance patient care.

Palmoplantar keratoderma (PPK): acquired and genetic causes of a not so rare disease

Palmoplantar keratodermas (PPK) comprise a heterogeneous group of keratinization disorders with hyperkeratotic thickening of palms and soles. Sporadic or acquired forms of PPKs and genetic or hereditary forms exist. Differentiation between acquired and hereditary forms is essential for adequate treatment and patient counseling. Acquired forms of PPK have many causes. A plethora of mutations in many genes can cause hereditary PPK. In recent years several new causative genes have been identified. Individual PPK may be quite heterogeneous with respect to presentation and associated symptoms. Since the various hereditary PPK - like many other monogenic diseases - exhibit a very low prevalence, making of the correct diagnosis is challenging and often requires a molecular genetic analysis. Knowledge about the large but quite heterogeneous group of hereditary PPK is also important to dissect the molecular mechanisms of epidermal differentiation on palms and soles, ultimately leading to targeted corrective therapies in the future.