Samedaydoctor has recently been able to offer advice and management for this chronic condition.
DSAP mainly affects the lower arms and legs bilaterally and arises more frequently on the lower legs. There may be few or innumerable lesions. The forehead and cheeks are affected in less than 10% of individuals and DSAP almost never occurs on the scalp, palms or soles. It tends to be more prominent in the summer and may appear less prominent in winter. New lesions have been provoked by ultraviolet light in sun lamps.
The lesions are composed of multiple irregular roundish, annular or polycyclic plaques, each of which has an elevated horny rim. The visibility of this rim is markedly accentuated by the application of an artificial tanning solution (dihydroxyacetone).
The smallest DSAP lesion is a 1–3 mm conical papule, skin coloured, brownish-red or brown in colour. It is based around a hair follicle containing a keratotic (scaly) plug. Larger plaques have a sharp, slightly raised, keratotic ring, a fraction of a millimetre thick, with a diameter of 10 mm or more. The skin within the ring is thinned and mildly reddened or slightly brown, and a pale ring may be seen just within the ridge. The ridge itself is often a darker brown than the rest of the lesion. The central area is most often pale and smooth, but it may be red, scaly, dry, or have scaly follicular plugs.
Sweating is absent within the lesions. Although most often asymptomatic, sun exposure or heat may cause them to itch or sting.
What are the complications of DSAP?
The development of squamous cell carcinoma (SCC) within a DSAP lesion is the main concern. This is uncommon (< 10% of individuals with DSAP develop SCC). However, many patients with DSAP have had significant exposure to the sun and may also have actinic keratoses and other forms of skin cancer (particularly basal cell carcinoma). SCC presents as a solitary tender enlarging scaly or ulcerated plaque or nodule. We can help people with this condition and a facebook forum has been organised so patients can communicate with each other about their experiences.