Laboratory parameters of 1st order – obligatory laboratory tests.
- Skin biopsies (sampling)/punch biopsies 3-6 mm in diameter under local anesthesia/local anesthesia) – to confirm the diagnosis (all suspected cases should be clarified histologically (fine tissue)!)Indication for a punch biopsy:
- Unclear diagnosis
- Appearance of new lesions such as ulcers (boils) or nodules
- High potency corticosteroid ointment is ineffective
- Suspicion of neoplasia (new formation)
Histological findings: flattened epidermis / epidermis (loss of the reteleisten / extensions of the epidermis into the dermis (dermis)); hyperkeratosis (excessive strong keratinization of the skin); often disordered basal cell layer; subepidermal (“below the epidermis”) thick zone of edematous collagen, reduction of elastic fibers, which may also be absent; in the keratinocytes (horn-forming cells) melanocytes (pigment-producing cells) are reduced or absent (resulting in external white porcelain-like patches).