(Ichthyosis follicularis; Psorospermosis; Darier’s disease)
Definition. – A rare, hypertrophic affection characterized by pin-head – to pea-sized, acuminated or rounded papules, often with central, conical plugs.
Symptoms – The peculiarity of the papule is that it contains a dark coloured horny plug which is embedded in a hair-follicle and projects above the surrounding skin surface. The plug is difficult to remove, and leaves a pit- like depression. The typical papules of this disease usually appear on the scalp, face, chest, groins and inguinal region. At first they are the color of the normal skin but later become brownish and often greasy-looking. Surrounding the horny plug there may be dark colored oily scales resembling those of seborrheic dermatitis. In the folds of the skin where there is much moisture, as in the groins, around the anus and behind the ears, the papules may enlarge, coalesce, and form warty elevations or become eroded and discharge an abundant seropurulent secretion.
Etiology and Pathology. – The view that this disease was due to psorosperms has been abandoned and heredity and contagion only only remain as possible causal factors. Only about thirty cases have been reported and in a majority of these it occurred in males, chiefly in childhood and adolescence. The pathology may be quoted from Macleod who concludes that “it is a type of dyskeratosis associated with a peculiar cellular degeneration which may affect any portion of the epidermis, but is frequently located at the upper third of the pilosebaceous follicle or the opening of a sweat-duct.”
Diagnosis. – This is based upon the peculiar papule with its distinctive plug and its tendency to become warty or eroded behind the ears or in the groins. It should be hard to confuse it with keratosis pilaris, dermatitis seborrhoica or molluscum contagiosum. The differential points of these diseases may be found under their respective descriptions.
Prognosis and Treatment. – Improvement may take place but no cures have been reported. Fortunately it does not appear to affect the general health. The X- rays in massive doses offer the most likely permanent benefit. Alkaline and saline baths with friction, followed or perhaps preceded by salicylic acid, sulphur and resorcin ointments in modern strength, have been used. Pyrogallol ointment has been recommended but should only be used on limited areas. Internal remedies must be based on the broadest general symptomatology.