Introduction Demographics Causes Clinical features Complications Diagnosis Differential diagnoses Treatment Outcome
Porokeratosis is an uncommon skin condition of abnormal keratinisation [1].
Porokeratosis plantaris, palmaris et disseminata (PPPD) is an extremely rare form of porokeratosis in which scaly red-brown annular patches arise on the patient's palms and soles and spread to the extremities and trunk [2].
The onset of PPPD is usually during the teenage years, although there are rare reports of the onset of PPPD later in life [3]. PPPD was originally reported to be twice as common in men than women [2].
PPPD generally worsens during summer [2].
Most often, PPPD occurs as a genetic autosomal dominant condition that runs in families [4]. However, sporadic cases may arise [5].
PPPD usually presents initially as red-brown annular patches on the patient's palms of the hands and soles of the feet. These lesions spread to the extremities and trunk forming reddish and slightly thinned small patches with defined borders [1,2].
PPPD is chronic and progressive and can affect the quality of life. There is a small risk of progression to cutaneous squamous cell carcinoma in long-standing cases [7].
The diagnosis of porokeratosis is usually made clinically but sometimes a biopsy is needed. The pathology of porokeratosis is very distinct.
The differential diagnosis for PPPD is mainly other forms of porokeratosis, especially DSAP. DSAP has similar skin lesions to PPPD on the patient's limbs, but its lesions are uncommon on the trunk and, usually, the hands and feet are spared. DSAP tends to affect sun-exposed areas whereas PPPD can affect any part of the body.
There is no known cure for PPPD and treatment is generally disappointing. Some patients respond well to the oral retinoids, acitretin or isotretinoin.
Topical treatments may include:
Physical destructive treatments may include:
Sun protection is very important as exposure to ultraviolet radiation may result in the development of skin cancer within the porokeratosis lesion.
PPPD is chronic and progressive. It tends to fluctuate in severity, often worsening in summer. Some people respond well to oral isotretinoin or acitretin, but most often the condition relapses when the medication is stopped.
There is a small risk of progression to cutaneous squamous cell carcinoma, so the skin lesions should be monitored.
