From the Guidelines
Parakeratosis is a critical histological marker for various skin disorders, and its types, including orthokeratotic, focal, and confluent parakeratosis, have distinct clinical significance in diagnosing and managing conditions like psoriasis, seborrheic dermatitis, and actinic keratosis 1.
Types of Parakeratosis
- Orthokeratotic parakeratosis: occurs in conditions like psoriasis, characterized by thick, scaly plaques due to rapid keratinocyte turnover preventing complete nuclear degradation.
- Focal parakeratosis: seen in conditions like seborrheic dermatitis, presenting as erythematous patches with yellowish scales on sebaceous gland-rich areas.
- Confluent parakeratosis: appears in inflammatory dermatoses such as lichen planus and eczema.
Clinical Significance
The clinical significance of parakeratosis lies in its diagnostic value, as the pattern and distribution help differentiate between various skin disorders. Treatment targets the underlying condition rather than parakeratosis itself, with options including:
- Topical corticosteroids for inflammatory conditions
- Vitamin D analogs for psoriasis
- Antifungals for seborrheic dermatitis
- Systemic immunomodulators for severe cases
Management of Actinic Keratosis
According to the guidelines of care for the management of actinic keratosis 1, treatment options include topically applied creams, gels, and solutions; cryosurgery; and photodynamic therapy (PDT). The selection of treatment is based on AK features, treatment-related factors, and patient characteristics and preferences. The primary patient-focused considerations for the treatment of AKs are the associated symptoms, the risk of progression to keratinocyte carcinoma, tolerability, burden of treatment, and the cosmetic appearance of the AKs before, during, and after treatment. Recommended topical agents for AK treatment include 5-fluorouracil (5-FU) and imiquimod 1.
From the Research
Parakeratosis Types
- Parakeratosis refers to incomplete maturation of epidermal keratinocytes, resulting in abnormal retention of nuclei in the stratum corneum 2
- It occurs in many diseases of the skin, particularly in psoriasis 2
- Other skin diseases that show parakeratosis include chronic eczema and squamous cell carcinoma 2
Clinical Significance
- Parakeratosis is associated with loss of inhibitor of differentiation 4 via promoter methylation 2
- Down-regulation of inhibitor of differentiation 4 messenger RNA has been demonstrated in psoriatic skin 2
- Parakeratosis can be a hallmark of various skin diseases, including porokeratosis, which consists of a keratinization disorder and can undergo malignant transformation 3
- Flegel's disease, a rare benign hyperkeratotic dermatosis, is also characterized by parakeratosis, discrete hyperkeratosis, and thinning or absence of the stratum granulosum 4
Treatment Options
- Treatment options for parakeratosis vary depending on the underlying skin disease, but may include topical or systemic retinoids, vitamin D analogs, and phototherapy 3, 5, 4
- Porokeratosis of Mibelli has shown good response to treatment with imiquimod cream and linear porokeratosis has responded well to topical or systemic retinoids 3
- High-dose oral vitamin D3 supplementation has been shown to improve the clinical efficacy of photodynamic therapy in patients with actinic keratoses 6