The symptoms of keratosis follicularis usually become apparent during the teen-age years often around puberty. Symptoms may develop in younger or older individuals, but rarely develop after the third or fourth decade of life. The severity of the disorder and the specific symptoms that develop vary, even among individuals within the same family.
The initial Lesions in keratosis follicularis are usually small, firm, greasy Bumps (papules) that are often skin-colored, brown or yellow-brown in color. The Lesions usually affect the areas of the body near sebaceous glands (sebaceous glands secrete oily grease) including the chest, back, forehead and scalp. Darier disease may also affect skin creases e.g. groin.
The skin Lesions associated with keratosis follicularis generally develop a brown, greasy crust and become thickened and warty (hyperkeratotic), scaly and darkened. The Lesions will slowly grow bigger eventually coming together (coalescing) to form discolored, warty Plaques that may cover extensive areas of the body particularly on the trunk. In extremely rare, severe cases, almost the entire body may be affected. The Lesions may cause persistent Itchiness (pruritus). Some patients have Fragile skin that Blisters or becomes raw (erosions) and painful.
The skin may develop bacterial, viral or fungal infections (secondary infections) that worsen (exacerbate) the condition. Infected skin Lesions may give off a distinct, unpleasant (malodorous) smell. The herpes simplex virus may be prone to infecting the Lesions and causes pain. Heat, exercise and sunlight may also worsen keratosis follicularis or cause a new outbreak of lesions.
Individuals with keratosis follicularis may have periods when few Lesions are present (remission). However, the Lesions tend to recur (relapse). Keratosis follicularis is usually worse in the summer and improves in the winter. Heat or sun often causes an outbreak.
Another common finding associated with keratosis follicularis is the development of multiple, small, yellow-brown, flattened wart-like (verrucous) Bumps (papules) on backs of the hands or feet. These Bumps may be the first sign of keratosis follicularis. Many affected individuals develop small horny Bumps called punctate keratoses or depressions (pits) on the palms and soles.
Most individuals with keratosis follicularis have abnormalities affecting the nails including fragile nails with splits along the length of the nail or red or white streaks that run up and down the nail with V-shaped notching at the free edge.
Sometimes the mucous membranes within the mouth develop small Bumps (papules). The roof of the mouth (palate) is most often affected. The gums, larynx and esophagus may also be affected. Darier disease can also affect the ducts of the salivary glands causing salivary gland obstruction. In some cases, Darier disease has developed on the mucous membranes of the anus and rectum.
Although in most people Darier disease is limited to the skin, additional symptoms have been reported in some cases including seizures, bipolar disorder, and learning disabilities.
Keratosis follicularis may -be restricted to a band of skin on one side of the body (segmental or linear keratosis follicularis).