Parapsoriasis

Parapsoriasis
Synonyms
Pronounce	N/A
Specialty	Dermatology
Symptoms	Skin rash, scaling, itching
Complications	N/A
Onset
Duration
Types	N/A
Causes	Unknown
Risks
Diagnosis	Skin biopsy, clinical examination
Differential diagnosis	Psoriasis, eczema, cutaneous T-cell lymphoma
Prevention	N/A
Treatment	Topical corticosteroids, phototherapy, systemic therapy
Medication
Prognosis	N/A
Frequency	Rare
Deaths

Parapsoriasis is a term used to describe a group of rare skin disorders that resemble psoriasis but have distinct differences in their clinical presentation and histopathology. These conditions are characterized by scaly patches or plaques on the skin, which can be persistent and may have a potential to progress to more serious conditions, such as cutaneous T-cell lymphoma.

Classification

Parapsoriasis is generally classified into two main types based on the size and characteristics of the lesions:

Small-plaque parapsoriasis

Small-plaque parapsoriasis, also known as "chronic superficial scaly dermatitis," is characterized by small, scaly patches that are usually less than 5 cm in diameter. These patches are often asymptomatic and can persist for many years without significant change. The lesions are typically found on the trunk and proximal extremities.

Large-plaque parapsoriasis

Large-plaque parapsoriasis is characterized by larger patches or plaques that are greater than 5 cm in diameter. These lesions may have a higher risk of progression to mycosis fungoides, a type of cutaneous T-cell lymphoma. The plaques are often found on the trunk and may be accompanied by itching.

Clinical Features

The clinical presentation of parapsoriasis can vary, but common features include:

• Scaly patches or plaques on the skin
• Lesions that are often asymptomatic but may be itchy
• Chronic and persistent nature
• Potential for progression to more serious conditions

Diagnosis

The diagnosis of parapsoriasis is primarily clinical, supported by histopathological examination of skin biopsies. Key features on biopsy include:

• Epidermal hyperplasia
• Parakeratosis
• Lymphocytic infiltrate in the dermis

Differential diagnosis includes psoriasis, eczema, and other forms of dermatitis.

Management

Management of parapsoriasis involves:

• Topical corticosteroids to reduce inflammation
• Phototherapy, such as narrowband UVB or PUVA
• Regular monitoring for signs of progression to cutaneous T-cell lymphoma

Prognosis

The prognosis of parapsoriasis varies depending on the type and potential for progression. Small-plaque parapsoriasis generally has a benign course, while large-plaque parapsoriasis requires careful monitoring due to the risk of progression to mycosis fungoides.

Related pages

• Psoriasis
• Mycosis fungoides
• Cutaneous T-cell lymphoma